Data Sheet
BMA423
Digital, triaxial acceleration sensor
Bosch Sensortec
Data Sheet BMA423
Part number(s)
0 273 141 292
Document revision
1.1
Release date
May 2019
Document number
BST-BMA423-DS000-01
Notes
Specifications are preliminary and subject to change without notice.
Product photos and pictures are for illustration purposes only and may
differ from the real product’s appearance.
Data Sheet
BMA423
Page 2
BMA423
12 bit, digital, triaxial acceleration sensor with intelligent on-chip motion-triggered interrupt features
optimized for wearable applications.
Key features
Small package size
Digital interface
Programmable functionality
On-chip FIFO
On-chip interrupt features
Ultra-low power
(Secondary) Auxiliary Interface
RoHS compliant, halogen-free
LGA package (12 pins), footprint 2mm x 2mm,
height 0.95 mm
SPI (4-wire, 3-wire), I²C, 2 interrupt pins
VDDIO voltage range: 1.2V to 3.6V
Acceleration ranges ±2g/±4g/±8g/±16g
Low-pass filter bandwidths 684Hz - =1.62V,
IOL 50ms
8. Read and store positive acceleration value of each axis from registers DATA_8 to DATA_13
9. Enable self-test and set negative self-test polarity ACC_SELF_TEST.acc_self_test_sign=
1b0)
10. Wait for > 50ms
11. Read and store negative acceleration value of each axis from registers DATA_8 to DATA_13
12. Calculate difference of positive and negative acceleration values and compare against
threshold values
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 49
4.10. Offset Compensation
BMA423 offers manual compensation as well as inline calibration.
Offset compensation is performed with pre-filtered data, and the offset is then applied to both, prefiltered and filtered data. If necessary the result of this computation is saturated to prevent any overflow
errors (the smallest or biggest possible value is set, depending on the sign).
The public offset compensation Registers OFFSET_0 to OFFSET_2 are images of the corresponding
registers in the NVM. With each image update the contents of the NVM registers are written to the
public registers. The public registers can be overwritten by the user at any time.
The offset compensation registers have a width of 8 bit using two’s complement notation. The offset
resolution (LSB) is 3.9 mg and the offset range is +- 0.5 g. Both are independent of the range setting.
Offset compensation needs to be enabled through NV_CONF.acc_off_en = 0b1
Manual Offset Compensation
The contents of the public compensation Register OFFSET_0 to OFFSET_2 may be set manually via
the digital interface. After modifying the Register OFFSET_0 to OFFSET_2 the next data sample is
not valid.
Offset compensation needs to be enabled through NV_CONF.acc_off_en.
Inline Calibration
For certain applications, it is often desirable to calibrate the offset once and to store the compensation
values permanently. This can be achieved by using manual offset compensation to determine the
proper compensation values and then storing these values permanently in the NVM.
Each time the device is reset, the compensation values are loaded from the non-volatile memory into
the image registers and used for offset compensation.
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 50
4.11. Non-Volatile Memory
The registers NV_CONF and OFFSET_0 to OFFSET_2 have an NVM backup which are accessible
by the user.
The content of the NVM is loaded to the image registers after a reset (either POR or softreset). As long
as the image update is in progress, STATUS.cmd_rdy is 0b0, otherwise it is 0b1.
The image registers can be read and written like any other register.
Writing to the NVM is a 4-step procedure:
1. Set PWR_CONF.adv_power_save = 0b0
2. Write the new contents to the image registers.
3. Write 0b1 to bit NVM_CONF.nvm_prog_en in order to unlock the NVM.
4. Write prog_nvm to the CMD register to trigger the write process.
Writing to the NVM always renews the entire NVM contents. It is possible to check the write status by
reading STATUS.cmd_rdy. While STATUS.cmd_rdy = 0b0, the write process is still in progress; when
STATUS.cmd_rdy = 0b1, writing is completed. An NVM write cycle can only be initiated, if
PWR_CONF.adv_power_save = 0b0.
Until boot phase is finished (after POR or softreset), the serial interface is not operational. The NVM
shadow registers must not be accessed during an ongoing NVM command (initiated through the
Register CMD). In all other cases, register can be read or written.
As long as an NVM read (during sensor boot and soft reset) or an NVM write is ongoing, writes to
sensor registers are discarded, reads return the Register STATUS independent of the read address.
4.12. Soft-Reset
A softreset can be initiated at any time by writing the command softreset (0xB6) to register CMD. The
softreset performs a fundamental reset to the device which is largely equivalent to a power cycle.
Following a delay, all user configuration settings are overwritten with their default state (setting stored
in the NVM) wherever applicable. This command is functional in all operation modes but must not be
performed while NVM writing operation is in progress.
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 51
5. Register Description
5.1. General Remarks
Registers can be read and written in all power configurations with the exception of FEATURES_IN and
FIFO_DATA which need PWR_CONF.adv_power_save set to 0b0.
5.2. Register Map
read/write
read only
write only
reserved
ID:
Register
Register
Default
Address
Name
Value
CMD
0x00
0x7E
0x7D
0x7C
PWR_CT
RL
PWR_C
ONF
7
6
5
4
3
0x00
reserved
0x03
-
-
reserved
-
-
reserved
-
-
reserved
0x00
off_acc_z
0x00
off_acc_y
0x00
off_acc_x
0x73
0x72
0x71
0x70
0x6F
0x6E
_2
OFFSET
_1
OFFSET
_0
NV_CON
F
0x00
reserved
0x6B
0x6A
F
reserved
NVM_C
ONF
0x00
0x00
er_save
acc_self_
acc_self_
test_amp
test_sign
reserved
spi_en
acc_self_
test_en
reserved
reserved
if_mode
reserved
spi3
nvm_pro
reserved
g_en
0x69
-
-
reserved
...
-
-
reserved
0x60
-
-
reserved
BST-BMA423-DS000-01 | Version 1.1 | May 2019
wakeup
sel
reserved
-
adv_pow
i2c_wdt_
-
IF_CON
fifo_self_
en
-
T
0x6C
aux_en
i2c_wdt_
reserved
0x00
reserved
en
-
LF_TES
acc_en
acc_off_
ACC_SE
0x6D
0
reserved
...
OFFSET
1
cmd
0x7B
0x74
2
reserved
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 52
INTERN
0x5F
AL_ERR
0x00
reserved
int_err_2
int_err_1
reserved
reserved
int1_drdy
int1_fwm
int1_ffull
wrist_tilt_
activity_t
step_cou
out
ype_out
nter_out
wrist_tilt_
activity_t
step_cou
out
ype_out
nter_out
OR
0x5E
FEATUR
ES_IN
0x00
features_in
0x5D
-
-
reserved
...
-
-
reserved
-
-
reserved
0x90
init_ctrl
0x5A
0x59
0x58
0x57
0x56
0x55
0x54
0x53
INIT_CT
RL
INT_MA
P_DATA
INT2_MA
P
INT1_MA
P
INT_LAT
CH
INT2_IO
_CTRL
INT1_IO
_CTRL
0x00
0x00
0x00
reserved
error_int
_out
error_int
_out
int2_drdy
any_no_
motion_o
ut
any_no_
motion_o
ut
int2_fwm
wakeup_
out
wakeup_
out
0x00
int2_ffull
reserved
reserved
reserved
0x00
reserved
input_en
0x00
reserved
input_en
output_e
n
output_e
n
-
-
reserved
...
-
-
reserved
0x50
-
-
reserved
0x02
write_data
0x4C
write_addr
0x42
read_addr
0x4E
0x4D
0x4C
0x4B
0x4A
AUX_W
R_DATA
AUX_W
R_ADDR
AUX_RD
_ADDR
AUX_IF_
CONF
AUX_DE
V_ID
-
0x83
aux_man
0x20
ONFIG_
0x10
reserved
od
lvl
edge_ctrl
aux_rd_burst
reserved
fifo_acc_
fifo_aux_
fifo_head
fifo_tag_i
fifo_tag_i
en
en
er_en
nt1_en
nt2_en
FIFO_C
ONFIG_
edge_ctrl
reserved
1
0x48
lvl
i2c_device_addr
FIFO_C
0x49
od
reserved
ual_en
reserved
int_latch
0x52
0x4F
reserved
0x02
0
BST-BMA423-DS000-01 | Version 1.1 | May 2019
reserved
reserved
fifo_time
fifo_stop
_en
_on_full
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
0x47
0x46
0x45
0x44
0x43
0x42
0x41
0x40
FIFO_W
TM_1
FIFO_W
TM_0
FIFO_D
OWNS
AUX_CO
NF
0x02
Page 53
reserved
fifo_water_mark_12_8
0x00
0x80
fifo_water_mark_7_0
acc_fifo_
acc_fifo_downs
filt_data
0x46
reserved
aux_offset
aux_odr
-
-
reserved
-
-
reserved
ACC_RA
NGE
ACC_CO
NF
0x01
0xA8
reserved
acc_perf
acc_range
acc_bwp
_mode
acc_odr
0x3F
-
-
reserved
...
-
-
reserved
-
-
0x2B
INTERN
0x2A
AL_STAT
0x00
reserved
odr_high
odr_50hz
_error
_error
US
0x29
0x28
0x27
0x26
0x25
0x24
0x23
0x22
axes_re
map_err
message
or
-
-
reserved
-
-
reserved
ACTIVIT
Y_TYPE
FIFO_DA
TA
FIFO_LE
NGTH_1
FIFO_LE
NGTH_0
TEMPER
ATURE
0x00
reserved
0x00
0x00
activity_type_out
fifo_data
reserved
fifo_byte_counter_13_8
0x00
fifo_byte_counter_7_0
-
reserved
0x00
temperature
0x00
step_counter_out_3
0x00
step_counter_out_2
0x00
step_counter_out_1
STEP_C
0x21
OUNTER
_3
STEP_C
0x20
OUNTER
_2
STEP_C
0x1F
OUNTER
_1
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 54
STEP_C
0x1E
OUNTER
0x00
step_counter_out_0
_0
0x1D
0x1C
0x1B
0x1A
0x19
0x18
INT_STA
TUS_1
INT_STA
TUS_0
EVENT
SENSOR
TIME_2
SENSOR
TIME_1
SENSOR
TIME_0
0x00
0x00
acc_drdy
_int
error_int
_out
reserved
any_no_
motion_o
ut
aux_drdy
reserved
_int
wakeup_
out
0x01
reserved
wrist_tilt_
activity_t
step_cou
out
ype_out
nter_out
0x00
sensor_time_15_8
0x00
sensor_time_7_0
acc_z_11_4
0x00
0x16
DATA_12
0x00
0x15
DATA_11
0x00
0x14
DATA_10
0x00
0x13
DATA_9
0x00
0x12
DATA_8
0x00
0x11
DATA_7
0x00
acc_z_3_0
reserved
acc_y_11_4
acc_y_3_0
reserved
acc_x_11_4
acc_x_3_0
reserved
aux_r_11_4
0x10
DATA_6
0x00
0x0F
DATA_5
0x00
0x0E
DATA_4
0x00
0x0D
DATA_3
0x00
0x0C
DATA_2
0x00
0x0B
DATA_1
0x00
0x0A
DATA_0
0x00
0x09
-
-
reserved
aux_r_3_0
reserved
aux_z_11_4
aux_z_3_0
reserved
aux_y_11_4
aux_y_3_0
reserved
aux_x_11_4
aux_x_3_0
reserved
...
-
-
reserved
0x04
-
-
reserved
0x03
STATUS
0x10
drdy_acc
reserved
drdy_aux
0x00
aux_err
fifo_err
reserved
0x02
ERR_RE
G
reserved
cted
sensor_time_23_16
DATA_13
ffull_int
por_dete
reserved
0x00
0x17
fwm_int
cmd_rdy
reserved
aux_man
error_code
0x01
-
-
reserved
0x00
CHIP_ID
0x13
chip_id
reserved
_op
cmd_err
fatal_err
1
0
FEATURES_IN
Register
Register
Default
Address
Name
Value
BST-BMA423-DS000-01 | Version 1.1 | May 2019
7
6
5
4
3
2
Bosch Sensortec
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BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 55
general_
0x5E:
0x3F
settings.
axes_re
0x00
map_z_a
reserved
xis_sign
mapping[
1]
general_
0x5E:
0x3E
settings.
axes_re
0x88
map_z_axis
mapping[
map_y_a
xis_sign
map_y_axis
map_x_a
xis_sign
map_x_axis
0]
general_
0x5E:
settings.c
0x3D
onfig_id[
0x00
identification
0x00
identification
0x00
reserved
1]
general_
0x5E:
settings.c
0x3C
onfig_id[
0]
0x5E:
0x3B
0x5E:
0x3A
0x5E:
0x39
0x5E:
0x38
wrist_tilt.
settings[
1]
wrist_tilt.
settings[
0x00
reserved
enable
0]
tap_doub
letap.sett
0x00
reserved
ings[1]
tap_doub
letap.sett
0x06
single_ta
reserved
sensitivity
p_en
ings[0]
enable
step_cou
0x5E:
nter.setti
0x37
ngs_26[1
0x00
reserved
en_activit
en_count
en_detec
reset_co
y
er
tor
unter
watermark_level
]
step_cou
0x5E:
nter.setti
0x36
ngs_26[0
0x00
watermark_level
0x00
param_25
0x0E
param_25
]
step_cou
0x5E:
nter.setti
0x35
ngs_25[1
]
0x5E:
step_cou
0x34
nter.setti
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 56
ngs_25[0
]
step_cou
0x5E:
nter.setti
0x33
ngs_24[1
0x00
param_24
0x01
param_24
0x00
param_23
0x03
param_23
0x00
param_22
0x01
param_22
0x01
param_21
0x00
param_21
0x3C
param_20
0xF0
param_20
0x00
param_19
]
step_cou
0x5E:
nter.setti
0x32
ngs_24[0
]
step_cou
0x5E:
nter.setti
0x31
ngs_23[1
]
step_cou
0x5E:
nter.setti
0x30
ngs_23[0
]
step_cou
0x5E:
nter.setti
0x2F
ngs_22[1
]
step_cou
0x5E:
nter.setti
0x2E
ngs_22[0
]
step_cou
0x5E:
nter.setti
0x2D
ngs_21[1
]
step_cou
0x5E:
nter.setti
0x2C
ngs_21[0
]
step_cou
0x5E:
nter.setti
0x2B
ngs_20[1
]
step_cou
0x5E:
nter.setti
0x2A
ngs_20[0
]
0x5E:
step_cou
0x29
nter.setti
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 57
ngs_19[1
]
step_cou
0x5E:
nter.setti
0x28
ngs_19[0
0x0C
param_19
0x00
param_18
0x01
param_18
0x00
param_17
0xA0
param_17
0x00
param_16
0x96
param_16
0x00
param_15
0x19
param_15
0x00
param_14
0x27
param_14
]
step_cou
0x5E:
nter.setti
0x27
ngs_18[1
]
step_cou
0x5E:
nter.setti
0x26
ngs_18[0
]
step_cou
0x5E:
nter.setti
0x25
ngs_17[1
]
step_cou
0x5E:
nter.setti
0x24
ngs_17[0
]
step_cou
0x5E:
nter.setti
0x23
ngs_16[1
]
step_cou
0x5E:
nter.setti
0x22
ngs_16[0
]
step_cou
0x5E:
nter.setti
0x21
ngs_15[1
]
step_cou
0x5E:
nter.setti
0x20
ngs_15[0
]
step_cou
0x5E:
nter.setti
0x1F
ngs_14[1
]
0x5E:
step_cou
0x1E
nter.setti
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 58
ngs_14[0
]
step_cou
0x5E:
nter.setti
0x1D
ngs_13[1
0x00
param_13
0x01
param_13
0x46
param_12
0x0C
param_12
0xE6
param_11
0xEC
param_11
0x04
param_10
0xC3
param_10
0x09
param_9
0x85
param_9
0x04
param_8
]
step_cou
0x5E:
nter.setti
0x1C
ngs_13[0
]
step_cou
0x5E:
nter.setti
0x1B
ngs_12[1
]
step_cou
0x5E:
nter.setti
0x1A
ngs_12[0
]
step_cou
0x5E:
nter.setti
0x19
ngs_11[1
]
step_cou
0x5E:
nter.setti
0x18
ngs_11[0
]
step_cou
0x5E:
nter.setti
0x17
ngs_10[1
]
step_cou
0x5E:
nter.setti
0x16
ngs_10[0
]
0x5E:
0x15
0x5E:
0x14
0x5E:
0x13
step_cou
nter.setti
ngs_9[1]
step_cou
nter.setti
ngs_9[0]
step_cou
nter.setti
ngs_8[1]
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
0x5E:
0x12
0x5E:
0x11
0x5E:
0x10
0x5E:
0x0F
0x5E:
0x0E
0x5E:
0x0D
0x5E:
0x0C
0x5E:
0x0B
0x5E:
0x0A
0x5E:
0x09
0x5E:
0x08
0x5E:
0x07
0x5E:
0x06
0x5E:
0x05
0x5E:
0x04
Page 59
step_cou
nter.setti
0xC3
param_8
0x6C
param_7
0xCD
param_7
0x7B
param_6
0x3F
param_6
0x00
param_5
0x04
param_5
0x7A
param_4
0xDB
param_4
0x01
param_3
0x3B
param_3
0x7B
param_2
0xD4
param_2
0x01
param_1
0x2D
param_1
ngs_8[0]
step_cou
nter.setti
ngs_7[1]
step_cou
nter.setti
ngs_7[0]
step_cou
nter.setti
ngs_6[1]
step_cou
nter.setti
ngs_6[0]
step_cou
nter.setti
ngs_5[1]
step_cou
nter.setti
ngs_5[0]
step_cou
nter.setti
ngs_4[1]
step_cou
nter.setti
ngs_4[0]
step_cou
nter.setti
ngs_3[1]
step_cou
nter.setti
ngs_3[0]
step_cou
nter.setti
ngs_2[1]
step_cou
nter.setti
ngs_2[0]
step_cou
nter.setti
ngs_1[1]
step_cou
nter.setti
ngs_1[0]
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
0x5E:
0x03
0x5E:
0x02
0x5E:
0x01
0x5E:
0x00
Page 60
any_moti
on.settin
0x00
z_en
y_en
x_en
duration
gs_2[1]
any_moti
on.settin
0x05
duration
gs_2[0]
any_moti
on.settin
0x00
gs_1[1]
reserved
nomotion
_sel
threshold
any_moti
on.settin
0xAA
threshold
gs_1[0]
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 61
Register (0x00) CHIP_ID
DESCRIPTION: Chip identification code
RESET: 0x13
DEFINITION (Go to register map):
Name
Register (0x00) CHIP_ID
Bit
7
6
Read/Write
R
R
Reset Value
0
0
Content
chip_id
Bit
3
2
Read/Write
R
R
Reset Value
0
0
Content
chip_id
chip_id: Chip identification code for BMA423.
5
R
0
4
R
1
1
R
1
0
R
1
5
n/a
0
reserved
1
R
0
cmd_err
4
R
0
error_code
0
R
0
fatal_err
Register (0x02) ERR_REG
DESCRIPTION: Reports sensor error conditions
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x02) ERR_REG
7
6
R
R
0
0
aux_err
fifo_err
3
2
R
R
0
0
error_code
fatal_err: Fatal Error, chip is not in operational state (Boot-, power-system). This flag will be reset only
by power-on-reset or softreset.
cmd_err: Command execution failed.
error_code: Error codes for persistent errors
error_code
0x00
no_error no error is reported
0x01
acc_err error in Register ACC_CONF
fifo_err: Error in FIFO detected: Input data was discarded in stream mode. This flag will be reset when
read.
aux_err: Error in I2C-Master detected. This flag will be reset when read.
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 62
Register (0x03) STATUS
DESCRIPTION: Sensor status flags
RESET: 0x10
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x03) STATUS
7
6
R
n/a
0
0
drdy_acc
reserved
3
2
n/a
R
0
0
reserved
aux_man_op
5
R
0
drdy_aux
1
n/a
0
reserved
4
R
1
cmd_rdy
0
n/a
0
aux_man_op: ‘1’(‘0’) indicate a (no) manual auxiliary interface operation is ongoing.
cmd_rdy: CMD decoder status. `0´ -> Command in progress `1´ -> Command decoder is ready to
accept a new command
drdy_aux: Data ready for auxiliary sensor. It gets reset when one auxiliary DATA register is read out
drdy_acc: Data ready for accelerometer. It gets reset when one accelerometer DATA register is read
out
Register (0x0A) DATA_0
DESCRIPTION: AUX_X(LSB)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x0A) DATA_0
7
6
R
R
0
0
aux_x_3_0
3
2
n/a
n/a
0
0
reserved
BST-BMA423-DS000-01 | Version 1.1 | May 2019
5
R
0
4
R
0
1
n/a
0
0
n/a
0
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 63
Register (0x0B) DATA_1
DESCRIPTION: AUX_X(MSB)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x0B) DATA_1
7
6
R
R
0
0
aux_x_11_4
3
2
R
R
0
0
aux_x_11_4
5
R
0
4
R
0
1
R
0
0
R
0
5
R
0
4
R
0
1
n/a
0
0
n/a
0
Register (0x0C) DATA_2
DESCRIPTION: AUX_Y(LSB)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x0C) DATA_2
7
6
R
R
0
0
aux_y_3_0
3
2
n/a
n/a
0
0
reserved
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 64
Register (0x0D) DATA_3
DESCRIPTION: AUX_Y(MSB)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x0D) DATA_3
7
6
R
R
0
0
aux_y_11_4
3
2
R
R
0
0
aux_y_11_4
5
R
0
4
R
0
1
R
0
0
R
0
5
R
0
4
R
0
1
n/a
0
0
n/a
0
Register (0x0E) DATA_4
DESCRIPTION: AUX_Z(LSB)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x0E) DATA_4
7
6
R
R
0
0
aux_z_3_0
3
2
n/a
n/a
0
0
reserved
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 65
Register (0x0F) DATA_5
DESCRIPTION: AUX_Z(MSB)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x0F) DATA_5
7
6
R
R
0
0
aux_z_11_4
3
2
R
R
0
0
aux_z_11_4
5
R
0
4
R
0
1
R
0
0
R
0
5
R
0
4
R
0
1
n/a
0
0
n/a
0
Register (0x10) DATA_6
DESCRIPTION: AUX_R(LSB)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x10) DATA_6
7
6
R
R
0
0
aux_r_3_0
3
2
n/a
n/a
0
0
reserved
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 66
Register (0x11) DATA_7
DESCRIPTION: AUX_R(MSB)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x11) DATA_7
7
6
R
R
0
0
aux_r_11_4
3
2
R
R
0
0
aux_r_11_4
5
R
0
4
R
0
1
R
0
0
R
0
5
R
0
4
R
0
1
n/a
0
0
n/a
0
Register (0x12) DATA_8
DESCRIPTION: ACC_X(LSB)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x12) DATA_8
7
6
R
R
0
0
acc_x_3_0
3
2
n/a
n/a
0
0
reserved
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 67
Register (0x13) DATA_9
DESCRIPTION: ACC_X(MSB)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x13) DATA_9
7
6
R
R
0
0
acc_x_11_4
3
2
R
R
0
0
acc_x_11_4
5
R
0
4
R
0
1
R
0
0
R
0
5
R
0
4
R
0
1
n/a
0
0
n/a
0
Register (0x14) DATA_10
DESCRIPTION: ACC_Y(LSB)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x14) DATA_10
7
6
R
R
0
0
acc_y_3_0
3
2
n/a
n/a
0
0
reserved
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 68
Register (0x15) DATA_11
DESCRIPTION: ACC_Y(MSB)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x15) DATA_11
7
6
R
R
0
0
acc_y_11_4
3
2
R
R
0
0
acc_y_11_4
5
R
0
4
R
0
1
R
0
0
R
0
5
R
0
4
R
0
1
n/a
0
0
n/a
0
Register (0x16) DATA_12
DESCRIPTION: ACC_Z(LSB)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x16) DATA_12
7
6
R
R
0
0
acc_z_3_0
3
2
n/a
n/a
0
0
reserved
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 69
Register (0x17) DATA_13
DESCRIPTION: ACC_Z(MSB)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x17) DATA_13
7
6
R
R
0
0
acc_z_11_4
3
2
R
R
0
0
acc_z_11_4
5
R
0
4
R
0
1
R
0
0
R
0
5
R
0
4
R
0
1
R
0
0
R
0
Register (0x18) SENSORTIME_0
DESCRIPTION: Sensor time
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x18) SENSORTIME_0
7
6
R
R
0
0
sensor_time_7_0
3
2
R
R
0
0
sensor_time_7_0
sensor_time_7_0: Sensor time in units of 39.0625 us.
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 70
Register (0x19) SENSORTIME_1
DESCRIPTION: Sensor time
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x19) SENSORTIME_1
7
6
R
R
0
0
sensor_time_15_8
3
2
R
R
0
0
sensor_time_15_8
5
R
0
4
R
0
1
R
0
0
R
0
5
R
0
4
R
0
1
R
0
0
R
0
sensor_time_15_8: Sensor time in units of 10 ms.
Register (0x1A) SENSORTIME_2
DESCRIPTION: Sensor time
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x1A) SENSORTIME_2
7
6
R
R
0
0
sensor_time_23_16
3
2
R
R
0
0
sensor_time_23_16
sensor_time_23_16: Sensor time in units of 2.56 s.
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 71
Register (0x1B) EVENT
DESCRIPTION: Sensor status flags
RESET: 0x01
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x1B) EVENT
7
6
n/a
n/a
0
0
reserved
3
2
n/a
n/a
0
0
reserved
5
n/a
0
4
n/a
0
1
n/a
0
0
R
1
por_detected
por_detected: '1' after device power up or softreset. Clear-on-read
Register (0x1C) INT_STATUS_0
DESCRIPTION: Interrupt/Feature Status. Will be cleared on read.
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x1C) INT_STATUS_0
7
6
R
R
0
0
error_int_out
any_no_motion_
out
3
2
R
R
0
0
wrist_tilt_out
activity_type_out
5
R
0
wakeup_out
4
n/a
0
reserved
1
R
0
step_counter_out
0
n/a
0
reserved
step_counter_out: Step-counter watermark or Step-detector output.
activity_type_out: Step counter activity output(Running, Walking, Still)
wrist_tilt_out: Wrist tilt output
wakeup_out: Wakeup output
any_no_motion_out: Any-motion/No-motion detection output
error_int_out: Error interrupt output
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 72
Register (0x1D) INT_STATUS_1
DESCRIPTION: Interrupt Status. Will be cleared on read.
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x1D) INT_STATUS_1
7
6
R
n/a
0
0
acc_drdy_int
reserved
3
2
n/a
n/a
0
0
reserved
5
R
0
aux_drdy_int
1
R
0
fwm_int
4
n/a
0
reserved
0
R
0
ffull_int
5
R
0
4
R
0
1
R
0
0
R
0
ffull_int: FIFO Full Interrupt
fwm_int: FIFO Watermark Interrupt
aux_drdy_int: Auxiliary sensor data ready interrupt
acc_drdy_int: Accelerometer data ready interrupt
Register (0x1E) STEP_COUNTER_0
DESCRIPTION: Step counting value byte-0
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x1E) STEP_COUNTER_0
7
6
R
R
0
0
step_counter_out_0
3
2
R
R
0
0
step_counter_out_0
step_counter_out_0: Step counting value byte-0 (least significant byte)
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 73
Register (0x1F) STEP_COUNTER_1
DESCRIPTION: Step counting value byte-1
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x1F) STEP_COUNTER_1
7
6
R
R
0
0
step_counter_out_1
3
2
R
R
0
0
step_counter_out_1
5
R
0
4
R
0
1
R
0
0
R
0
5
R
0
4
R
0
1
R
0
0
R
0
step_counter_out_1: Step counting value byte-1
Register (0x20) STEP_COUNTER_2
DESCRIPTION: Step counting value byte-2
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x20) STEP_COUNTER_2
7
6
R
R
0
0
step_counter_out_2
3
2
R
R
0
0
step_counter_out_2
step_counter_out_2: Step counting value byte-2
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 74
Register (0x21) STEP_COUNTER_3
DESCRIPTION: Step counting value byte-3
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x21) STEP_COUNTER_3
7
6
R
R
0
0
step_counter_out_3
3
2
R
R
0
0
step_counter_out_3
5
R
0
4
R
0
1
R
0
0
R
0
step_counter_out_3: Step counting value byte-3 (most significant byte)
Register (0x22) TEMPERATURE
DESCRIPTION: Contains the temperature value of the sensor
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x22) TEMPERATURE
7
6
R
R
0
0
temperature
3
2
R
R
0
0
temperature
5
R
0
4
R
0
1
R
0
0
R
0
temperature: Temperature value in two's complement representation in units of 1 Kelvin: 0x00
corresponds to 23 degree Celsius.
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 75
Register (0x24) FIFO_LENGTH_0
DESCRIPTION: FIFO byte count register (LSB)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x24) FIFO_LENGTH_0
7
6
R
R
0
0
fifo_byte_counter_7_0
3
2
R
R
0
0
fifo_byte_counter_7_0
5
R
0
4
R
0
1
R
0
0
R
0
fifo_byte_counter_7_0: Current fill level of FIFO buffer.
Register (0x25) FIFO_LENGTH_1
DESCRIPTION: FIFO byte count register (MSB)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x25) FIFO_LENGTH_1
7
6
n/a
n/a
0
0
reserved
3
2
R
R
0
0
fifo_byte_counter_13_8
5
4
R
R
0
0
fifo_byte_counter_13_8
1
0
R
R
0
0
fifo_byte_counter_13_8: FIFO byte counter bits 13..8
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 76
Register (0x26) FIFO_DATA
DESCRIPTION: FIFO data output register
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x26) FIFO_DATA
7
6
R
R
0
0
fifo_data
3
2
R
R
0
0
fifo_data
5
R
0
4
R
0
1
R
0
0
R
0
fifo_data: FIFO read data.
Register (0x27) ACTIVITY_TYPE
DESCRIPTION: Step counter activity output(Running, Walking, Still)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x27) ACTIVITY_TYPE
7
6
n/a
n/a
0
0
reserved
3
2
n/a
n/a
0
0
reserved
5
n/a
0
4
n/a
0
1
R
0
activity_type_out
0
R
0
activity_type_out: Step counter activity output(Running, Walking, Still)
activity_type_out
0x00
still
user not moving
0x01
walking
user walking
0x02
running
user running
0x03
unknown unknown state
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 77
Register (0x2A) INTERNAL_STATUS
DESCRIPTION: Error bits and message indicating internal status
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Register (0x2A) INTERNAL_STATUS
7
6
R
R
0
0
odr_high_error
odr_50hz_error
Bit
Read/Write
Reset Value
Content
3
R
0
message
2
R
0
5
R
0
axes_remap_erro
r
1
R
0
4
R
0
message
0
R
0
message: Internal Status Message
message
0x00
not_init
ASIC is not initialized
0x01
init_ok
ASIC initialized
0x02
init_err
Initialization error
0x03
drv_err
Invalid driver
0x04
sns_stop Sensor stopped
axes_remap_error: Axes remapped wrongly because a source axis is not assigned to more than one
target axis.
odr_50hz_error: The minimum bandwidth conditions are not respected for the features which require
50 Hz data.
odr_high_error: The minimum bandwidth conditions are not respected for the Wakeup Detection.
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 78
Register (0x40) ACC_CONF
DESCRIPTION: Sets the output data rate, the bandwidth, and the read mode of the acceleration
sensor
RESET: 0xA8
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x40) ACC_CONF
7
6
RW
RW
1
0
acc_perf_mode
acc_bwp
3
2
RW
RW
1
0
acc_odr
5
RW
1
4
RW
0
1
RW
0
0
RW
0
acc_odr: ODR in Hz. The output data rate is independent of the power mode setting for the sensor,
but not all settings are supported in all power modes.
acc_odr
0x00
reserved Reserved
0x01
odr_0p78 25/32
0x02
odr_1p5
25/16
0x03
odr_3p1
25/8
0x04
odr_6p25 25/4
0x05
odr_12p5 25/2
0x06
odr_25
25
0x07
odr_50
50
0x08
odr_100
100
0x09
odr_200
200
0x0a
odr_400
400
0x0b
odr_800
800
0x0c
odr_1k6
1600
0x0d
odr_3k2
Reserved
0x0e
odr_6k4
Reserved
0x0f
odr_12k8 Reserved
acc_bwp: Bandwidth parameter, determines filter configuration (acc_perf_mode=1) and averaging for
undersampling mode (acc_perf_mode=0)
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 79
acc_bwp
0x00
osr4_avg1
0x01
osr2_avg2
0x02
0x03
0x04
0x05
0x06
0x07
acc_perf_mode = 1 -> OSR4 mode; acc_perf_mode = 0 -> no averaging
acc_perf_mode = 1 -> OSR2 mode; acc_perf_mode = 0 -> average 2
samples
norm_avg4 acc_perf_mode = 1 -> normal mode; acc_perf_mode = 0 -> average 4
samples
cic_avg8
acc_perf_mode = 1 -> Reserved; acc_perf_mode = 0 -> average 8
samples
res_avg16
acc_perf_mode = 1 -> Reserved; acc_perf_mode = 0 -> average 16
samples
res_avg32
acc_perf_mode = 1 -> Reserved; acc_perf_mode = 0 -> average 32
samples
res_avg64
acc_perf_mode = 1 -> Reserved; acc_perf_mode = 0 -> average 64
samples
res_avg128 acc_perf_mode = 1 -> Reserved; acc_perf_mode = 0 -> average 128
samples
acc_perf_mode: Select accelerometer filter performance mode:
acc_perf_mode
0x00
cic_avg averaging mode.
0x01
cont
continuous filter function.
Register (0x41) ACC_RANGE
DESCRIPTION: Selection of the Accelerometer g-range
RESET: 0x01
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x41) ACC_RANGE
7
6
n/a
n/a
0
0
reserved
3
2
n/a
n/a
0
0
reserved
BST-BMA423-DS000-01 | Version 1.1 | May 2019
5
n/a
0
4
n/a
0
1
RW
0
acc_range
0
RW
1
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 80
acc_range: Accelerometer g-range
acc_range
0x00
range_2g
+/-2g
0x01
range_4g
+/-4g
0x02
range_8g
+/-8g
0x03
range_16g +/-16g
Register (0x44) AUX_CONF
DESCRIPTION: Sets the output data rate of the Auxiliary interface
RESET: 0x46
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x44) AUX_CONF
7
6
RW
RW
0
1
aux_offset
3
2
RW
RW
0
1
aux_odr
5
RW
0
4
RW
0
1
RW
1
0
RW
0
aux_odr: Select the poll rate for the sensor attached to the Auxiliary interface.
aux_odr
0x00
0x01
0x02
0x03
0x04
0x05
0x06
0x07
0x08
0x09
0x0a
0x0b
0x0c
0x0d
0x0e
0x0f
reserved
odr_0p78
odr_1p5
odr_3p1
odr_6p25
odr_12p5
odr_25
odr_50
odr_100
odr_200
odr_400
odr_800
odr_1k6
odr_3k2
odr_6k4
odr_12k8
Reserved
25/32
25/16
25/8
25/4
25/2
25
50
100
200
400
800
Reserved
Reserved
Reserved
Reserved
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 81
aux_offset: trigger-readout offset in units of 2.5 ms. If set to zero, the offset is maximum, i.e. after
readout a trigger is issued immediately.
Register (0x45) FIFO_DOWNS
DESCRIPTION: Configure Accelerometer downsampling rates for FIFO
RESET: 0x80
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x45) FIFO_DOWNS
7
6
RW
RW
1
0
acc_fifo_filt_data acc_fifo_downs
3
2
n/a
n/a
0
0
reserved
5
RW
0
4
RW
0
1
n/a
0
0
n/a
0
acc_fifo_downs: Downsampling for accelerometer data (2**acc_fifo_downs)
acc_fifo_filt_data: selects filtered or unfiltered Accelerometer data for fifo
acc_fifo_filt_data
0x00
unfiltered Unfiltered data
0x01
filtered
Filtered data
Register (0x46) FIFO_WTM_0
DESCRIPTION: FIFO Watermark level LSB
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x46) FIFO_WTM_0
7
6
RW
RW
0
0
fifo_water_mark_7_0
3
2
RW
RW
0
0
fifo_water_mark_7_0
BST-BMA423-DS000-01 | Version 1.1 | May 2019
5
RW
0
4
RW
0
1
RW
0
0
RW
0
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 82
Register (0x47) FIFO_WTM_1
DESCRIPTION: FIFO Watermark level MSB
RESET: 0x02
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Register (0x47) FIFO_WTM_1
7
6
n/a
n/a
0
0
reserved
Bit
Read/Write
Reset Value
Content
3
2
RW
RW
0
0
fifo_water_mark_12_8
5
n/a
0
1
RW
1
4
RW
0
fifo_water_mark_
12_8
0
RW
0
5
n/a
0
4
n/a
0
1
RW
1
fifo_time_en
0
RW
0
fifo_stop_on_full
Register (0x48) FIFO_CONFIG_0
DESCRIPTION: FIFO frame content configuration
RESET: 0x02
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x48) FIFO_CONFIG_0
7
6
n/a
n/a
0
0
reserved
3
2
n/a
n/a
0
0
reserved
fifo_stop_on_full: Stop writing samples into FIFO when FIFO is full.
fifo_stop_on_full
0x00
disable do not stop writing to FIFO when full
0x01
enable Stop writing into FIFO when full.
fifo_time_en: Return sensortime frame after the last valid data frame.
fifo_time_en
0x00
disable do not return sensortime frame
0x01
enable return sensortime frame
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 83
Register (0x49) FIFO_CONFIG_1
DESCRIPTION: FIFO frame content configuration
RESET: 0x10
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x49) FIFO_CONFIG_1
7
6
n/a
RW
0
0
reserved
fifo_acc_en
3
2
RW
RW
0
0
fifo_tag_int1_en
fifo_tag_int2_en
5
RW
0
fifo_aux_en
1
n/a
0
reserved
4
RW
1
fifo_header_en
0
n/a
0
fifo_tag_int2_en: FIFO interrupt 2 tag enable
fifo_tag_int2_en
0x00
disable disable tag
0x01
enable enable tag
fifo_tag_int1_en: FIFO interrupt 1 tag enable
fifo_tag_int1_en
0x00
disable disable tag
0x01
enable enable tag
fifo_header_en: FIFO frame header enable
fifo_header_en
0x00
disable no header is stored (output data rate of all enabled sensors need to be
identical)
0x01
enable header is stored
fifo_aux_en: Store Auxiliary data in FIFO (all 3 axes)
fifo_aux_en
0x00
disable no Auxiliary data is stored
0x01
enable Auxiliary data is stored
fifo_acc_en: Store Accelerometer data in FIFO (all 3 axes)
fifo_acc_en
0x00
disable no Accelerometer data is stored
0x01
enable Accelerometer data is stored
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 84
Register (0x4B) AUX_DEV_ID
DESCRIPTION: Auxiliary interface slave device id
RESET: 0x20
DEFINITION (Go to register map):
Name
Register (0x4B) AUX_DEV_ID
Bit
7
6
Read/Write
RW
RW
Reset Value
0
0
Content
i2c_device_addr
Bit
3
2
Read/Write
RW
RW
Reset Value
0
0
Content
i2c_device_addr
i2c_device_addr: I2C device address of Auxiliary slave
5
RW
1
4
RW
0
1
RW
0
0
n/a
0
reserved
5
n/a
0
4
n/a
0
1
RW
1
aux_rd_burst
0
RW
1
Register (0x4C) AUX_IF_CONF
DESCRIPTION: Auxiliary interface configuration
RESET: 0x83
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x4C) AUX_IF_CONF
7
6
RW
n/a
1
0
aux_manual_en
reserved
3
2
n/a
n/a
0
0
reserved
aux_rd_burst: Burst data length (1,2,6,8 byte)
aux_rd_burst
0x00
BL1 Burst length 1
0x01
BL2 Burst length 2
0x02
BL6 Burst length 6
0x03
BL8 Burst length 8
aux_manual_en: Enable auxiliary interface manual mode.
aux_manual_en
0x00
disable Data mode
0x01
enable Setup mode
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 85
Register (0x4D) AUX_RD_ADDR
DESCRIPTION: Auxiliary interface read register address
RESET: 0x42
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x4D) AUX_RD_ADDR
7
6
RW
RW
0
1
read_addr
3
2
RW
RW
0
0
read_addr
5
RW
0
4
RW
0
1
RW
1
0
RW
0
5
RW
0
4
RW
0
1
RW
0
0
RW
0
read_addr: Address to read
Register (0x4E) AUX_WR_ADDR
DESCRIPTION: Auxiliary interface write register address
RESET: 0x4C
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x4E) AUX_WR_ADDR
7
6
RW
RW
0
1
write_addr
3
2
RW
RW
1
1
write_addr
write_addr: Address to write
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 86
Register (0x4F) AUX_WR_DATA
DESCRIPTION: Auxiliary interface write data
RESET: 0x02
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x4F) AUX_WR_DATA
7
6
RW
RW
0
0
write_data
3
2
RW
RW
0
0
write_data
5
RW
0
4
RW
0
1
RW
1
0
RW
0
write_data: Data to write
Register (0x53) INT1_IO_CTRL
DESCRIPTION: Configure the electrical behaviour of the interrupt pins
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x53) INT1_IO_CTRL
7
6
n/a
n/a
0
0
reserved
3
2
RW
RW
0
0
output_en
od
5
n/a
0
1
RW
0
lvl
4
RW
0
input_en
0
RW
0
edge_ctrl
edge_ctrl: Configure trigger condition of INT1 pin (input)
edge_ctrl
0x00
level_tr Level
0x01
edge_tr Edge
lvl: Configure level of INT1 pin
lvl
0x00 active_low active low
0x01 active_high active high
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 87
od: Configure behaviour of INT1 pin to open drain.
od
0x00 push_pull
push-pull
0x01 open_drain open drain
output_en: Output enable for INT1 pin
output_en
0x00
off Output disabled
0x01
on Output enabled
input_en: Input enable for INT1 pin
input_en
0x00
off Input disabled
0x01
on Input enabled
Register (0x54) INT2_IO_CTRL
DESCRIPTION: Configure the electrical behaviour of the interrupt pins
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x54) INT2_IO_CTRL
7
6
n/a
n/a
0
0
reserved
3
2
RW
RW
0
0
output_en
od
5
n/a
0
1
RW
0
lvl
4
RW
0
input_en
0
RW
0
edge_ctrl
edge_ctrl: Configure trigger condition of INT2 pin (input)
edge_ctrl
0x00
level_tr Level
0x01
edge_tr Edge
lvl: Configure level of INT2 pin
lvl
0x00 active_low active low
0x01 active_high active high
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 88
od: Configure behaviour of INT2 pin to open drain.
od
0x00 push_pull
push-pull
0x01 open_drain open drain
output_en: Output enable for INT2 pin
output_en
0x00
off Output disabled
0x01
on Output enabled
input_en: Input enable for INT2 pin
input_en
0x00
off Input disabled
0x01
on Input enabled
Register (0x55) INT_LATCH
DESCRIPTION: Configure interrupt modes
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x55) INT_LATCH
7
6
n/a
n/a
0
0
reserved
3
2
n/a
n/a
0
0
reserved
5
n/a
0
4
n/a
0
1
n/a
0
0
RW
0
int_latch
int_latch: Latched/non-latched/temporary interrupt modes
int_latch
0x00
none
non latched
0x01
permanent latched
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
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BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 89
Register (0x56) INT1_MAP
DESCRIPTION: Interrupt/Feature mapping on INT1
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x56) INT1_MAP
7
6
RW
RW
0
0
error_int_out
any_no_motion_
out
3
2
RW
RW
0
0
wrist_tilt_out
activity_type_out
5
RW
0
wakeup_out
4
n/a
0
reserved
1
RW
0
step_counter_out
0
n/a
0
reserved
step_counter_out: Step-counter watermark or Step-detector output.
activity_type_out: Step counter activity output(Running, Walking, Still)
wrist_tilt_out: Wrist tilt output
wakeup_out: Wakeup output
any_no_motion_out: Any-motion/No-motion detection output
error_int_out: Error interrupt output
Register (0x57) INT2_MAP
DESCRIPTION: Interrupt/Feature mapping on INT2
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x57) INT2_MAP
7
6
RW
RW
0
0
error_int_out
any_no_motion_
out
3
2
RW
RW
0
0
wrist_tilt_out
activity_type_out
5
RW
0
wakeup_out
4
n/a
0
reserved
1
RW
0
step_counter_out
0
n/a
0
reserved
step_counter_out: Step-counter watermark or Step-detector output.
activity_type_out: Step counter activity output(Running, Walking, Still)
wrist_tilt_out: Wrist tilt output
wakeup_out: Wakeup output
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
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BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 90
any_no_motion_out: Any-motion/No-motion detection output
error_int_out: Error interrupt output
Register (0x58) INT_MAP_DATA
DESCRIPTION: Interrupt mapping hardware interrupts
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x58) INT_MAP_DATA
7
6
n/a
RW
0
0
reserved
int2_drdy
3
2
n/a
RW
0
0
reserved
int1_drdy
5
RW
0
int2_fwm
1
RW
0
int1_fwm
4
RW
0
int2_ffull
0
RW
0
int1_ffull
5
RW
0
4
RW
1
1
RW
0
0
RW
0
int1_ffull: FIFO Full interrupt mapped to INT1
int1_fwm: FIFO Watermark interrupt mapped to INT1
int1_drdy: Data Ready interrupt mapped to INT1
int2_ffull: FIFO Full interrupt mapped to INT2
int2_fwm: FIFO Watermark interrupt mapped to INT2
int2_drdy: Data Ready interrupt mapped to INT2
Register (0x59) INIT_CTRL
DESCRIPTION: Start initialization
RESET: 0x90
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x59) INIT_CTRL
7
6
RW
RW
1
0
init_ctrl
3
2
RW
RW
0
0
init_ctrl
init_ctrl: Start initialization
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 91
Register (0x5E) FEATURES_IN
DESCRIPTION: Feature configuration read/write port
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x5E) FEATURES_IN
7
6
RW
RW
0
0
features_in
3
2
RW
RW
0
0
features_in
5
RW
0
4
RW
0
1
RW
0
0
RW
0
features_in: Feature configuration read/write data
Address Bit
Name
any_motion
0x5E:
settings_1
0x00
10...0 threshold
11
0x5E:
0x02
nomotion_sel
settings_2
Reset
Any-motion / No-motion detection 0x00AA
general configuration flags - part 1
Slope threshold value for Any-motion / 0xAA
No-motion detection in 5.11g format.
Range is 0 to 1g. Default value is 0xAA
= 83mg.
Indicates if Nomotion (1) or Any-motion 0x0
(0) is selected; default value is 0 – Anymotion.
0x0005
x_en
y_en
z_en
Any-motion / No-motion detection
general configuration flags - part 2
Defines the number of consecutive
data points for which the threshold
condition must be respected, for
interrupt assertion.
It is expressed in in 50 Hz samples (20
ms). Range is 0 to 163sec. Default
value is 5=100ms.
Enables the feature on a per-axis basis
Enables the feature on a per-axis basis
Enables the feature on a per-axis basis
settings_1
Step Counter setting
0x012D
12...0 duration
13
14
15
step_counter
Description
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Access
RW
RW
0x5
RW
0x0
0x0
0x0
RW
RW
RW
Bosch Sensortec
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BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
0x5E:
0x04
0x5E:
0x06
0x5E:
0x08
0x5E:
0x0A
0x5E:
0x0C
0x5E:
0x0E
0x5E:
0x10
0x5E:
0x12
0x5E:
0x14
0x5E:
0x16
0x5E:
0x18
0x5E:
0x1A
0x5E:
0x1C
0x5E:
0x1E
0x5E:
0x20
0x5E:
0x22
0x5E:
0x24
0x5E:
0x26
0x5E:
0x28
0x5E:
0x2A
0x5E:
0x2C
15...0 param_1
15...0
15...0
15...0
15...0
15...0
15...0
15...0
15...0
15...0
15...0
15...0
15...0
15...0
15...0
15...0
15...0
15...0
15...0
15...0
15...0
settings_2
param_2
settings_3
param_3
settings_4
param_4
settings_5
param_5
settings_6
param_6
settings_7
param_7
settings_8
param_8
settings_9
param_9
settings_10
param_10
settings_11
param_11
settings_12
param_12
settings_13
param_13
settings_14
param_14
settings_15
param_15
settings_16
param_16
settings_17
param_17
settings_18
param_18
settings_19
param_19
settings_20
param_20
settings_21
param_21
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Page 92
Step Counter param 1
0x12D
Step Counter setting
Step Counter param 2
Step Counter setting
Step Counter param 3
Step Counter setting
Step Counter param 4
Step Counter setting
Step Counter param 5
Step Counter setting
Step Counter param 6
Step Counter setting
Step Counter param 7
Step Counter setting
Step Counter param 8
Step Counter setting
Step Counter param 9
Step Counter setting
Step Counter param 10
Step Counter setting
Step Counter param 11
Step Counter setting
Step Counter param 12
Step Counter setting
Step Counter param 13
Step Counter setting
Step Counter param 14
Step Counter setting
Step Counter param 15
Step Counter setting
Step Counter param 16
Step Counter setting
Step Counter param 17
Step Counter setting
Step Counter param 18
Step Counter setting
Step Counter param 19
Step Counter setting
Step Counter param 20
Step Counter setting
Step Counter param 21
0x7BD4
0x7BD4
0x013B
0x13B
0x7ADB
0x7ADB
0x0004
0x4
0x7B3F
0x7B3F
0x6CCD
0x6CCD
0x04C3
0x4C3
0x0985
0x985
0x04C3
0x4C3
0xE6EC
0xE6EC
0x460C
0x460C
0x0001
0x1
0x0027
0x27
0x0019
0x19
0x0096
0x96
0x00A0
0xA0
0x0001
0x1
0x000C
0xC
0x3CF0
0x3CF0
0x0100
0x100
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
RW
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BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
0x5E:
0x2E
0x5E:
0x30
0x5E:
0x32
0x5E:
0x34
0x5E:
0x36
settings_22
15...0 param_22
settings_23
15...0 param_23
settings_24
15...0 param_24
settings_25
15...0 param_25
settings_26
9...0
watermark_level
10
reset_counter
11
12
13
en_detector
en_counter
en_activity
tap_doubletap
0x5E:
0x38
0
3...1
wrist_tilt
0x5E:
0x3A
settings
enable
sensitivity
4
single_tap_en
0
settings
enable
general_settings
0x5E:
config_id
0x3C
15...0 identification
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Page 93
Step Counter setting
Step Counter param 22
Step Counter setting
Step Counter param 23
Step Counter setting
Step Counter param 24
Step Counter setting
Step Counter param 25
Step Counter and Step Detector
Settings
Watermark level; the Step-counter will
trigger output every time this number of
steps are counted. Holds implicitly a
20x factor, so the range is 0 to 20460,
with resolution of 20 steps. If 0, the
output is disabled.
Flag to reset the counted steps. This is
only interpreted if the step counter is
enabled.
Enables the Step Detector.
Enables the Step Counter.
Enables
the
activity
detection(Running, Walking, Still)
0x0001
0x1
0x0003
0x3
0x0001
0x1
0x000E
0xE
0x0000
RW
RW
RW
RW
0x0
RW
0x0
RW
0x0
0x0
0x0
RW
RW
RW
Tap general configuration flags
Enables the feature
Configures Tap sensitivity, the range
goes from 0 (high sensitive) to 7 (low
sensitive).
Flag for enabling single tap detection
(and disabling double tap). By default
double tap detection is being enabled.
0x0006
0x0
0x3
RW
RW
0x0
RW
Wrist tilt configuration flags
Enables the feature
0x0000
0x0
RW
Describes configuration identification 0x0000
code
Describes configuration identification 0x0
code
R
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BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
0x5E:
0x3E
1...0
2
4...3
5
7...6
8
axes_remapping
map_x_axis
Describes axes remapping
Map the x axis to desired axis.
Value Name
Description
0x00 x axis
Map to x-axis
0x01 y axis
Map to y-axis
0x02 z axis
Map to z-axis
0x03 reserved reserved
map_x_axis_sign Map the x axis sign to the desired one.
Value Name
Description
0x00 nonClear this bit to
inverted non invert the x
axis
0x01 inverted Set this bit to
invert the x axis
map_y_axis
Map the y axis to desired axis
Value Name
Description
0x00 x axis
Map to x-axis
0x01 y axis
Map to y-axis
0x02 z axis
Map to z-axis
0x03 reserved reserved
map_y_axis_sign Map the y axis sign to the desired one
Value Name
Description
0x00 nonClear this bit to
inverted non invert the y
axis
0x01 inverted Set this bit to
invert the y axis
map_z_axis
Map the z axis to desired axis
Value Name
Description
0x00 x axis
Map to x-axis
0x01 y axis
Map to y-axis
0x02 z axis
Map to z-axis
0x03 reserved reserved
map_z_axis_sign Map the z axis sign to the desired one
Value Name
Description
0x00 nonClear this bit to
inverted non invert the z
axis
0x01 inverted Set this bit to
invert the z axis
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Page 94
0x0088
0x0
RW
0x0
RW
0x1
RW
0x0
RW
0x2
RW
0x0
RW
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BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 95
Register (0x5F) INTERNAL_ERROR
DESCRIPTION: Internal error flags
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x5F) INTERNAL_ERROR
7
6
n/a
n/a
0
0
reserved
3
2
n/a
R
0
0
reserved
int_err_2
5
n/a
0
4
n/a
0
1
R
0
int_err_1
0
n/a
0
reserved
int_err_1: Internal error flag - long processing time, processing halted
int_err_2: Internal error flag - fatal error, processing halted
Register (0x6A) NVM_CONF
DESCRIPTION: NVM controller mode (Prog/Erase or Read only)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x6A) NVM_CONF
7
6
n/a
n/a
0
0
reserved
3
2
n/a
n/a
0
0
reserved
5
n/a
0
4
n/a
0
1
RW
0
nvm_prog_en
0
n/a
0
reserved
nvm_prog_en: Enable NVM programming
nvm_prog_en
0x00
disable disable
0x01
enable enable
BST-BMA423-DS000-01 | Version 1.1 | May 2019
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BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 96
Register (0x6B) IF_CONF
DESCRIPTION: Serial interface settings
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x6B) IF_CONF
7
6
n/a
n/a
0
0
reserved
3
2
n/a
n/a
0
0
reserved
5
n/a
0
1
n/a
0
4
RW
0
if_mode
0
RW
0
spi3
spi3: Configure SPI Interface Mode for primary interface
spi3
0x00 spi4 SPI 4-wire mode
0x01 spi3 SPI 3-wire mode
if_mode: Auxiliary interface configuration
if_mode
0x00
p_auto_s_off
Auxiliary interface:off
0x01
p_auto_s_mag Auxilary interface:Magnetometer
Register (0x6D) ACC_SELF_TEST
DESCRIPTION: Settings for the sensor self-test configuration and trigger
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x6D) ACC_SELF_TEST
7
6
n/a
n/a
0
0
reserved
3
2
RW
RW
0
0
acc_self_test_am acc_self_test_sig
p
n
BST-BMA423-DS000-01 | Version 1.1 | May 2019
5
n/a
0
4
n/a
0
1
n/a
0
reserved
0
RW
0
acc_self_test_en
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BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 97
acc_self_test_en: Enable accelerometer self-test
acc_self_test_en
0x00
disabled disabled
0x01
enabled enabled
acc_self_test_sign: select sign of self-test excitation as
acc_self_test_sign
0x00
negative negative
0x01
positive positive
acc_self_test_amp: select amplitude of the selftest deflection:
acc_self_test_amp
0x00
low low
0x01
high high
Register (0x70) NV_CONF
DESCRIPTION: NVM backed configuration bits.
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x70) NV_CONF
7
6
n/a
n/a
0
0
reserved
3
2
RW
RW
0
0
acc_off_en
i2c_wdt_en
5
n/a
0
4
n/a
0
1
RW
0
i2c_wdt_sel
0
RW
0
spi_en
spi_en: disable the I2C and enable SPI for the primary interface, when it is in autoconfig mode
spi_en
0x00
disabled I2C enabled
0x01
enabled I2C disabled
i2c_wdt_sel: Select timer period for I2C Watchdog
i2c_wdt_sel
0x00
wdt_short I2C watchdog timeout after 1.25 ms
0x01
wdt_long I2C watchdog timeout after 40 ms
i2c_wdt_en: I2C Watchdog at the SDI pin in I2C interface mode
BST-BMA423-DS000-01 | Version 1.1 | May 2019
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BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 98
i2c_wdt_en
0x00
Disable Disable I2C watchdog
0x01
Enable Enable I2C watchdog
acc_off_en: Add the offset defined in the off_acc_[xyz] OFFSET register to filtered and unfiltered
Accelerometer data
acc_off_en
0x00
disabled Disabled
0x01
enabled Enabled
Register (0x71) OFFSET_0
DESCRIPTION: Offset compensation for Accelerometer X-axis (NVM backed)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x71) OFFSET_0
7
6
RW
RW
0
0
off_acc_x
3
2
RW
RW
0
0
off_acc_x
5
RW
0
4
RW
0
1
RW
0
0
RW
0
off_acc_x: Accelerometer offset compensation (X-axis).
Register (0x72) OFFSET_1
DESCRIPTION: Offset compensation for Accelerometer Y-axis (NVM backed)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x72) OFFSET_1
7
6
RW
RW
0
0
off_acc_y
3
2
RW
RW
0
0
off_acc_y
BST-BMA423-DS000-01 | Version 1.1 | May 2019
5
RW
0
4
RW
0
1
RW
0
0
RW
0
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BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 99
off_acc_y: Accelerometer offset compensation (Y-axis).
Register (0x73) OFFSET_2
DESCRIPTION: Offset compensation for Accelerometer Z-axis (NVM backed)
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x73) OFFSET_2
7
6
RW
RW
0
0
off_acc_z
3
2
RW
RW
0
0
off_acc_z
5
RW
0
4
RW
0
1
RW
0
0
RW
0
5
n/a
0
4
n/a
0
1
RW
1
fifo_self_wakeup
0
RW
1
adv_power_save
off_acc_z: Accelerometer offset compensation (Z-axis).
Register (0x7C) PWR_CONF
DESCRIPTION: Power mode configuration register
RESET: 0x03
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x7C) PWR_CONF
7
6
n/a
n/a
0
0
reserved
3
2
n/a
n/a
0
0
reserved
adv_power_save
0x00
aps_off advanced power save disabled (fast clk always enabled).
0x01
aps_on advanced power mode enabled (slow clk is active when no
measurement is ongoing.)
fifo_self_wakeup
0x00
fsw_off FIFO read disabled in advanced power saving mode.
0x01
fsw_on FIFO read enabled after interrupt in advanced power saving mode.
BST-BMA423-DS000-01 | Version 1.1 | May 2019
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BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 100
Register (0x7D) PWR_CTRL
DESCRIPTION: Sensor enable register
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x7D) PWR_CTRL
7
6
n/a
n/a
0
0
reserved
3
2
n/a
RW
0
0
reserved
acc_en
5
n/a
0
4
n/a
0
1
n/a
0
reserved
0
RW
0
aux_en
aux_en
0x00
mag_off Disables the auxiliary sensor.
0x01
mag_on Enables the auxiliary sensor.
acc_en
0x00
acc_off Disables the Accelerometer.
0x01
acc_on Enables the Accelerometer.
BST-BMA423-DS000-01 | Version 1.1 | May 2019
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BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 101
Register (0x7E) CMD
DESCRIPTION: Command Register
RESET: 0x00
DEFINITION (Go to register map):
Name
Bit
Read/Write
Reset Value
Content
Bit
Read/Write
Reset Value
Content
Register (0x7E) CMD
7
6
RW
RW
0
0
cmd
3
2
RW
RW
0
0
cmd
5
RW
0
4
RW
0
1
RW
0
0
RW
0
cmd: Available commands (Note: Register will always read as 0x00):
cmd
0xa0 nvm_prog Writes the NVM backed registers into NVM
0xb0 fifo_flush Clears all data in the FIFO, does not change FIFO_CONFIG and FIFO_DOWNS
registers
0xb6 softreset
Triggers a reset, all user configuration settings are overwritten with their default
state
BST-BMA423-DS000-01 | Version 1.1 | May 2019
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BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 102
6. Digital Interfaces
6.1. Interfaces
Beside the standard primary interface (I2C and SPI configurable), where sensor acts as a slave to the
application processor, BMA423 supports an auxiliary interface. See picture below.
If the auxiliary interface is enabled, the BMA423 can be connected to an external sensor (e.g. a
magnetometer) in order to build a 6-DoF solution. Then the BMA423 will act as a master to the external
sensor, reading the sensor data automatically and providing it to the application processor via the
primary interface.
6 DoF
AP
I2C / SPI
primary interface
BMA423
MAG Interface
I2C
auxiliary interface
BMM150
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Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 103
6.2. Primary Interface
By default, the BMA423 operates in I2C mode. The BMA423 interface can also be configured to
operate in a SPI 4-wire configuration. It can also be re-configured by software to work in 3-wire mode
instead of 4-wire mode.
All 3 possible digital interfaces share partly the same pins. The mapping for the primary interface of
the BMA423 is given in the following table:
Pin#
Name
I/O Type
Description
1
SDO
Digital I/O
2
SDX
Digital I/O
5
INT1
Digital I/O
6
INT2
Digital I/O
10
12
CSB
SCX
Digital in
Digital in
Serial data output in SPI
Address select in I²C mode
see chapter 7.2
SDA serial data I/O in I²C
SDI serial data input in SPI 4W
SDA serial data I/O in SPI 3W
Interrupt output 1 (default)
(Input for external FIFO sync) *
Interrupt output 2 (default)
(Input for external FIFO sync) *
Chip select for SPI mode
SCK for SPI serial clock
SCL for I²C serial clock
Connect to (Primary IF)
in SPI4W in SPI3W
in I2C
SDO
DNC (float)
GND for
default I2C
addr.
SDI
SDA
SDA
INT1
INT1
INT1
(FIFO sync) (FIFO sync) (FIFO sync)
INT2
INT2
INT2
(FIFO sync) (FIFO sync) (FIFO sync)
CSB
CSB
VDDIO
SCK
SCK
SCL
* INT1 and/or INT2 can also be configured as an input in case the external data synchronization in FIFO is used. See chapter 0. If INT1
and/or INT2 are not used, please do not connect them (DNC).
The following table shows the electrical specifications of the interface pins:
Parameter
Symbol
Condition
Min
Typ
Max
Units
Pull-up Resistance,
CSB pin
Rup
Internal Pull-up
Resistance to
VDDIO
75
100
125
k
Input Capacitance
Cin
5
pF
I²C Bus Load
Capacitance (max.
drive capability)
CI2C_Load
400
pF
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Data Sheet
BMA423
Page 104
6.3. Primary Interface I2C/SPI Protocol Selection
The protocol is automatically selected based on the chip select CSB pin behavior after power-up.
At reset / power-up, BMA423 is in I2C mode. If CSB is connected to VDDIO during power-up and not
changed the sensor interface works in I2C mode. For using I2C, it is recommended to hard-wire the
CSB line to VDDIO. Since power-on-reset is only executed when, both VDD and VDDIO are
established, there is no risk of incorrect protocol detection due to power-up sequence.
If CSB sees a rising edge after power-up, the BMA423 interface switches to SPI until a reset or the
next power-up occurs. Therefore, a CSB rising edge is needed before starting the SPI communication.
Hence, it is recommended to perform a SPI single read of register CHIP_ID (the obtained value will
be invalid) before the actual communication start, in order to use the SPI interface.
If toggling of the CSB bit is not possible without data communication, there is in addition the spi_en bit
in Register NV_CONF, which can be used to permanently set the primary interface to SPI without the
need to toggle the CSB pin at every power-up or reset.
6.4. SPI interface and protocol
The timing specification for SPI of the BMA423 is given in the following table:
SPI timing, valid at VDDIO ≥ 1.71V
Parameter
Symbol
Condition
Clock Frequency
fSPI
Max. Load on
SDI or SDO =
30pF, VDDIO ≥
1.62 V
VDDIO < 1.62V
SCK Low Pulse
SCK High Pulse
SCK Low Pulse
SCK High Pulse
SDI Setup Time
SDI Hold Time
SDO Output Delay
CSB Setup Time
CSB Hold Time
Idle time between
write accesses,
suspend mode, lowpower mode 1
Idle time after write
and read access,
active state
BST-BMA423-DS000-01 | Version 1.1 | May 2019
tSCKL
tSCKH
tSCKL
tSCKH
tSDI_setup
tSDI_hold
tSDO_OD
tCSB_setup
tCSB_hold
VDDIO>=1.62V
VDDIO>=1.62V
Min
Max
Units
10
MHz
7
MHz
45
45
VDDIO Master
I²C write
Multi-byte writes are supported without restriction on normal registers with auto-increment, on special
registers with address trap.
I²C read access:
I²C read access also can be used to read one or multiple data bytes in one sequence.
A read sequence consists of a one-byte I²C write phase followed by the I²C read phase. The two parts
of the transmission must be separated by a repeated start condition (S). The I²C write phase addresses
the slave and sends the register address to be read. After slave acknowledges the transmission, the
master generates again a start condition and sends the slave address together with a read bit (RW =
1). Then the master releases the bus and waits for the data bytes to be read out from slave. After each
data byte the master has to generate an acknowledge bit (ACKS = 0) to enable further data transfer.
A NACKM (ACKS = 1) from the master stops the data being transferred from the slave. The slave
releases the bus so that the master can generate a STOP condition and terminate the transmission.
The register address is automatically incremented and, therefore, more than one byte can be
sequentially read out. Once a new data read transmission starts, the start address will be set to the
register address specified since the latest I²C write command. By default the start address is set at
0x00. In this way repetitive multi-bytes reads from the same starting address are possible.
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Data Sheet
BMA423
Slave I2C ID
Start
S
0
0
1
1
0
0
0
R/W
ACK
0
0
Page 112
Register address (0x12)
X
0
0
1
0
0
ACK
1
0
0
Data byte
Repeat
Start
Sr
Slave I2C ID
0
0
1
1
0
0
0
R/W
ACK
1
0
Data byte
Register data - address 0x12
X
X
X
X
X
X
X
Register data - address 0x13
ACK
X
0
X
X
X
Data byte
…
X
X
X
X
X
X
X
X
X
X
X
X
X
X
0
…
0
X
X
X
X
X
X
X
ACK
X
0
…
Data byte
Register data - address 0x16
X
X
Register data - address 0x15
ACK
Data byte
…
X
Data byte
Register data - address 0x14
Master -> Slave
Slave -> Master
X
ACK
X
X
Register data - address 0x17
ACK
X
0
X
X
X
X
X
X
X
NACK Stop
X
1
P
In order to prevent the I²C slave of the device to lock-up the I²C bus, a watchdog timer (WDT) is
implemented. The WDT observes internal I²C signals and resets the I²C interface if the bus is lockedup by the BMA423. The activity and the timer period of the WDT can be configured through the bits
NV_CONF.i2c_wdt_en and NV_CONF.i2c_wdt_sel.
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Data Sheet
BMA423
Page 113
6.6. SPI and I²C Access Restrictions
In order to allow for the correct internal synchronization of data written to the BMA423, certain access
restrictions apply for consecutive write accesses or a write/read sequence through the SPI as well as
I2C interface. The required waiting period depends on whether the device is operating in normal mode
or other modes.
As illustrated in the figure below, an interface idle time of at least 2 µs is required following a write
operation when the device operates in normal mode. In suspend mode an interface idle time of least
1000 µs is required.
X-after-Write
Write-Operation
X-Operation
Register Update Period
(> 2us / 450us)
Post-Write Access Timing Constraints
6.7. Auxiliary Interface
The BMA423 allows attaching an external sensor (MAG-sensor) to a BMA423 via the auxiliary
interface. The connection diagrams for the auxiliary interface are depicted in the chapter 7.3. The
timings of the secondary I2C interface are the same as for the primary I2C interface, see chapter 6.5.
BM423 acts as a master of the secondary interface, controls the data acquisition of the MAG-sensor
(slave of the secondary interface) and presents the data to the application processor (AP) in the user
registers of the BMA423 through the primary interface. No external pull-up resistors need to be
connected, since an internal pull-up can be configured in the BMA423 (default value: internal pull-up
is off, please contact your regional sales representative if you want to use this functionality). No
additional I2C master or slave devices must be attached to the magnetometer interfaces.
The BMA423 autonomously reads out the sensor data from BMM150 without intervention of the AP
and stores the data in its data registers (per default) and FIFO (see Register
FIFO_CONFIG_1.fifo_aux_en). The initial setup of the BMM150 after power-on is done through
indirect addressing in the BMA423. From a system perspective the initialization for BMM150 when
attached to BMA423 should be possible within 100ms.
More information about the usage of Auxiliary Interface can be found in chapter 4.8.
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Data Sheet
BMA423
Page 114
7. Pin-out and Connection Diagrams
7.1. Pin-out
Top View
Bottom View
Pads not visible!
Pads visible!
Pin description
Pin#
Name
I/O Type
1
SDO
Digital I/O
2
SDX
Digital I/O
3
VDDIO
Supply
4
ASDA
Digital I/O
5
INT1
Digital I/O
6
INT2
Digital I/O
7
VDD
Supply
8
9
10
GNDIO
GND
CSB
Ground
Ground
Digital in
Description
Serial data output in SPI
Address select in I²C mode
see chapter 7.2
SDA serial data I/O in I²C
SDI serial data input in SPI 4W
SDA serial data I/O in SPI 3W
Digital I/O supply voltage (1.2V
… 3.6V)
Serial data I/O – Secondary
Interface (I²C Master for
Magnetometer)
Interrupt output 1 (default)
(Input for external FIFO sync) *
Interrupt output 2 (default)
(Input for external FIFO sync) *
Power supply for analog & digital
domain (1.62V … 3.6V)
Ground for I/O
Ground for digital & analog
Chip select for SPI mode
11
ASCL
Digital out
Digital clock (out) – Secondary
Interface (I²C Master for
Magnetometer)
12
SCX
Digital in
SCK for SPI serial clock
SCL for I²C serial clock
in SPI 4W
Connect to
In SPI 3W
in I²C
SDO
DNC (float)
GND for default I2C
addr.
SDI
SDA
SDA
VDDIO
VDDIO
VDDIO
VDDIO/
GNDIO/NC or
(ASDA Secondary
interface)
INT1
(FIFO sync)
INT2
(FIFO sync)
VDDIO/
GNDIO/NC or
(ASDA Secondary
interface)
INT1
(FIFO sync)
INT2
(FIFO sync)
VDD
VDD
VDD
GND
GND
CSB
VDDIO/
GNDIO/NC or
(ASCL Secondary
interface)
GND
GND
CSB
VDDIO/
GNDIO/ NC or
(ASCL Secondary
interface)
GND
GND
VDDIO
SCK
SCK
VDDIO/ GNDIO/NC
or
(ASDA - Secondary
interface)
INT1
(FIFO sync)
INT2
(FIFO sync)
VDDIO/ GNDIO/
NC or (ASCL Secondary
interface)
SCL
* INT1 and/or INT2 can also be configured as an input in case the external data synchronization in FIFO is used. See chapter 4.5. If INT1
and/or INT2 are not used, please do not connect them (DNC).
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Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 115
7.2. Connection Diagrams without Auxiliary Interface
SPI
3-wire
SCK
SDX
2
VDDIO
3
ASDA
4
ASCL
12
11
10
CSB
BMA423 9
GND
Top View
8
(Pads not visible!)
100nF
6
7
CS
100nF
GNDIO
VDD
VDD
INT2
5
INT1
VDDIO
1
SCX
MOSI/
MISO
SDO
GND
INT1 INT2
It is recommended to use 100nF decoupling capacitors at pin 3 (VDDIO) and pin 7 (VDD).
4-wire
SCK
1
MOSI
SDX
2
VDDIO
3
ASDA
4
11
10
CSB
BMA423 9
GND
Top View 8
(Pads not visible!)
5
6
INT2
100nF
12
INT1
VDDIO
ASCL
SDO
SCX
MISO
7
CS
100nF
GNDIO
VDD
VDD
GND
INT1 INT2
It is recommended to use 100nF decoupling capacitors at pin 3 (VDDIO) and pin 7 (VDD).
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Data Sheet
BMA423
Page 116
I2C
SCL
SDO
1
SDX
2
VDDIO
3
ASDA
4
11
10
CSB
BMA423 9
GND
Top View
8
(Pads not visible!)
100nF
5
6
INT2
VDDIO
12
INT1
SDA
ASCL
=1
=0
SCX
I2C_ID.0
7
100nF
GNDIO
VDD
VDD
GND
INT1 INT2
It is recommended to use 100nF decoupling capacitors at pin 3 (VDDIO) and pin 7 (VDD).
7.3. Connection Diagrams with Auxiliary Interface
SPI
3-wire
SCK
ASDA
ASCL
SDX
2
VDDIO
3
ASDA
4
12
11
10
CSB
BMA423 9
GND
5
6
INT2
Top View
8
(Pads not visible!)
INT1
100nF
ASCL
VDDIO
1
SCX
MOSI
MISO
SDO
7
to BMM
CS
100nF
GNDIO
VDD
VDD
GND
INT1 INT2
It is recommended to use 100nF decoupling capacitors at pin 3 (VDDIO) and pin 7 (VDD).
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Data Sheet
BMA423
Page 117
4-wire
SCK
ASDA
ASCL
1
MOSI
SDX
2
12
11
10
CSB
BMA423 9
GND
ASDA
4
100nF
5
6
INT2
VDDIO
Top View
3
8
(Pads not visible!)
INT1
VDDIO
ASCL
SDO
SCX
MISO
to BMM
CS
100nF
GNDIO
7
VDD
VDD
GND
INT1 INT2
It is recommended to use 100nF decoupling capacitors at pin 3 (VDDIO) and pin 7 (VDD).
I2C
SCL
ASDA
ASCL
SDX
2
VDDIO
3
ASDA
4
100nF
12
11
10
CSB
BMA423 9
GND
Top View
8
(Pads not visible!)
5
6
INT2
VDDIO
1
INT1
SDA
SDO
ASCL
=1
=0
SCX
I2C_ID.0
7
to BMM
100nF
GNDIO
VDD
VDD
GND
INT1 INT2
It is recommended to use 100nF decoupling capacitors at pin 3 (VDDIO) and pin 7 (VDD).
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Data Sheet
BMA423
Page 118
8. Package
8.1. Package outline dimensions
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Data Sheet
BMA423
Page 119
8.2. Sensing axis orientation
If the sensor is accelerated in the indicated directions, the corresponding channel will deliver a positive
acceleration signal (dynamic acceleration). If the sensor is at rest and the force of gravity is acting
along the indicated directions, the output of the corresponding channel will be negative (static
acceleration).
Example: If the sensor is at rest or at uniform motion in a gravity field according to the figure given
below, the output signals are:
• ± 0g for the X channel
• ± 0g for the Y channel
• + 1g for the Z channel
The following table lists all corresponding output signals on X, Y, and Z while the sensor is at rest or
at uniform motion in a gravity field under assumption of a ±4g range setting, a 12 bit resolution, and a
top down gravity vector as shown above.
Sensor Orientation
(gravity vector ↓)
upright
Output Signal X
0g / 0 LSB
1g / 511 LSB
0g / 0 LSB
-1g / -512 LSB
0g / 0 LSB
0g / 0 LSB
Output Signal Y
-1g / -512 LSB
0g / 0 LSB
1g / 511 LSB
0g / 0 LSB
0g / 0 LSB
0g / 0 LSB
Output Signal Z
0g / 0 LSB
0g / 0 LSB
0g / 0 LSB
0g / 0 LSB
1g / 511 LSB
-1g / -512 LSB
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Data Sheet
BMA423
Page 120
For reference the figure below shows the Android device orientation with an integrated BMA423.
BMA423
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Data Sheet
BMA423
Page 121
8.3. Landing pattern recommendation
The recommended landing pattern for the BMA423 on customer’s PCB is given in the following figure.
It is recommended to avoid any wiring underneath the BMA423 (shaded area).
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Data Sheet
BMA423
Page 122
8.4. Marking
Mass production
Labeling
ZZ
CCC
Name
Symbol
Remark
Internal Code
ZZ
internal
Counter ID
CCC
3 alphanumeric digits, variable
to generate trace-code.
Pin 1 identifier
top side
•
--
Name
Symbol
Remark
Internal Code
X
internal
Eng. sample ID
E, N
2 alphanumeric digits, fixed to identify
engineering sample, N = “C”
Sample ID
CC
2 alphanumeric digits, variable
to generate trace-code.
Pin 1 identifier
top side
•
--
Engineering samples
Labeling
XE
NCC
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Data Sheet
BMA423
Page 123
8.5. Soldering guidelines
The moisture sensitivity level of the BMA423E sensors corresponds to JEDEC Level 1, see also
-
IPC/JEDEC J-STD-020C "Joint Industry Standard: Moisture/Reflow Sensitivity Classification for
non-hermetic Solid State Surface Mount Devices"
IPC/JEDEC J-STD-033A "Joint Industry Standard: Handling, Packing, Shipping and Use of
Moisture/Reflow Sensitive Surface Mount Devices"
The sensor fulfils the lead-free soldering requirements of the above-mentioned IPC/JEDEC standard,
i.e. reflow soldering with a peak temperature up to 260°C.
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Data Sheet
BMA423
Page 124
8.6. Handling instructions
Micromechanical sensors are designed to sense acceleration with high accuracy even at low
amplitudes and contain highly sensitive structures inside the sensor element. The MEMS sensor can
tolerate mechanical shocks up to several thousand g's. However, these limits might be exceeded in
conditions with extreme shock loads such as e.g. hammer blow on or next to the sensor, dropping of
the sensor onto hard surfaces etc.
We recommend to avoid g-forces beyond the specified limits during transport, handling and mounting
of the sensors in a defined and qualified installation process.
This device has built-in protections against high electrostatic discharges or electric fields (e.g. 2kV
HBM); however, anti-static precautions should be taken as for any other CMOS component. Unless
otherwise specified, proper operation can only occur when all terminal voltages are kept within the
supply voltage range. Unused inputs must always be tied to a defined logic voltage level.
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Data Sheet
BMA423
Page 125
8.7. Tape and Reel specification
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Data Sheet
BMA423
Page 126
8.8. Environmental safety
The BMA423 sensor meets the requirements of the EC restriction of hazardous substances (RoHS)
directive, see also:
Directive 2011/65/EU of the European Parliament and of the Council of 8 September 2011 on
the restriction of the use of certain hazardous substances in electrical and electronic
equipment.
Halogen content
The BMA423 is halogen-free. For more details on the corresponding analysis results please contact
your Bosch Sensortec representative.
Internal package structure
Within the scope of Bosch Sensortec’s ambition to improve its products and secure the mass product
supply, Bosch Sensortec qualifies additional sources (e.g. 2 nd source) for the LGA package of the
BMA423.
While Bosch Sensortec took care that all of the technical packages parameters are described above
are 100% identical for all sources, there can be differences in the chemical content and the internal
structural between the different package sources.
However, as secured by the extensive product qualification process of Bosch Sensortec, this has no
impact to the usage or to the quality of the BMA423 product.
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Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 127
9. Legal disclaimer
9.1. Engineering samples
Engineering Samples are marked with an asterisk (*) or (e). Samples may vary from the valid technical
specifications of the product series contained in this data sheet. They are therefore not intended or fit
for resale to third parties or for use in end products. Their sole purpose is internal client testing. The
testing of an engineering sample may in no way replace the testing of a product series. Bosch
Sensortec assumes no liability for the use of engineering samples. The Purchaser shall indemnify
Bosch Sensortec from all claims arising from the use of engineering samples.
9.2. Product use
Bosch Sensortec products are developed for the consumer goods industry. They may only be used
within the parameters of this product data sheet. They are not fit for use in life-sustaining or security
sensitive systems. Security sensitive systems are those for which a malfunction is expected to lead to
bodily harm or significant property damage. In addition, they are not fit for use in products which
interact with motor vehicle systems.
The resale and/or use of products are at the purchaser’s own risk and his own responsibility. The
examination of fitness for the intended use is the sole responsibility of the Purchaser.
The purchaser shall indemnify Bosch Sensortec from all third party claims arising from any product
use not covered by the parameters of this product data sheet or not approved by Bosch Sensortec
and reimburse Bosch Sensortec for all costs in connection with such claims.
The purchaser must monitor the market for the purchased products, particularly with regard to product
safety, and inform Bosch Sensortec without delay of all security relevant incidents.
9.3. Application examples and hints
With respect to any examples or hints given herein, any typical values stated herein and/or any
information regarding the application of the device, Bosch Sensortec hereby disclaims any and all
warranties and liabilities of any kind, including without limitation warranties of non-infringement of
intellectual property rights or copyrights of any third party. The information given in this document shall
in no event be regarded as a guarantee of conditions or characteristics. They are provided for
illustrative purposes only and no evaluation regarding infringement of intellectual property rights or
copyrights or regarding functionality, performance or error has been made.
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
Data Sheet
BMA423
Page 128
10.Document history and modification
Rev. No
Chapter
Description of modification/changes
Date
Document creation
Fixed typos
Changed CSB recommendation for I²C
07 Aug 2017
4.8
6.2, 7.1
1.0
1.1
May 2019
Bosch Sensortec GmbH
Gerhard-Kindler-Strasse 9
72770 Reutlingen / Germany
contact@bosch-sensortec.com
www.bosch-sensortec.com
Modifications reserved | Printed in Germany
Specifications subject to change without notice
Document number: BST-BMA423-DS000-01
Revision_1.1_May_2019
BST-BMA423-DS000-01 | Version 1.1 | May 2019
Revision_1.0_August_2017
Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
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