PIXI™ click
PID: MIKROE-2817
Weight: 28 g
PIXI™ click is equipped with MAX11300 IC from Maxim Integrated, which features Maxim
Integrated's versatile, proprietary PIXI™ technology - it is the industry's first configurable 20channel mixed-signal data converter. Besides the 12bit multichannel SAR ADC and buffered
DAC, it also features one internal and two external temperature sensors for tracking the junction
and the environmental temperatures. Adjacent pairs of ports can be configured as logic-level
translators for open-drain devices or analog switches. Each port is individually configurable with
up to four selectable voltage ranges within -10 V to +10 V.
PIXI™ ports provide highly flexible hardware configuration for 12-bit mixed-signal
applications. The MAX11300 is best suited for applications that demand a mixture of several
analog and digital functions, such as monitoring and adjusting the bias on the power amplifiers,
digital level shifters, automatic fan speed controllers, etc. Actually, it can easily adapt to specific
application requirements, allowing for an easy reconfiguration, which makes it usable in virtually
any embedded application.
How does it work?
The main component of PIXI™ click is the MAX11300 integrated circuit. The main feature of
this IC is the proprietary PIXI™ technology. PIXI™ is an abbreviation for the Programmable
mIXed signal In/Out, a technology that allows very flexible routing of both digital and analog
signals. The MAX11300 IC has 20 configurable mixed-signal I/O ports. Each port can be
independently configured as a DAC output, an ADC input, a GPI, a GPO, or an analog switch
terminal. User-controllable parameters are available for each of those configurations. The device
also features one internal and two external temperature sensors with the ±1˚C accuracy. The
device uses the SPI Mode 0 interface for the communication with the controller, with the clock
up to 20MHz.
Analog to Digital Converter
The MAX11300 device features a12bit successive approximation (SAR) ADC module, which
can sample signals on a single port up to 400Ksmp/S. Like all the segments of this device, it also
offers great flexibility; the signal can be both unipolar or bipolar. Each ADC-configured port can
be programmed for one of four input voltage ranges: 0V to +10V, -5V to +5V, -10V to 0V, and
0V to +2.5V. There are two inputs for the reference voltage, but also internal reference voltage
of 2.5V can be used, instead.
The converter can be triggered by the CNVT# pin, routed to the PWM pin of the mikroBUS™.
This pin has to stay in the LOW logic state for at least 0.5 µs to trigger the conversion. There are
several modes of conversion, which include sampling on a single port, or sweeping through all
the configured ADC ports.
ADC offers the averaging feature, too. It can average readings of the ADC-configured ports to
blocks of 2, 4, 8, 16, 32, 64, or 128 conversion results.
Digital to Analog Converter
The buffered DAC converter is also 12bit, which can output up to 25Ksmp/s on a single port.
The output stage of the DAC is equipped with the driver, which offers ±10V on output and high
current capability, by using the dedicated power supplies (AVDDIO, AVSSIO pins of the
PIXI™ header). The DAC module also uses internal or external reference voltage. The flexibility
of the PIXI™ routing also allows monitoring of the DAC configured ports by utilizing the ADC
module. All the DAC ports are protected from overcurrent and such events can generate an
interrupt on the INT pin, routed to the INT# pin on the mikroBUS™.
General‐Purpose Inputs and Outputs (GPIO)
Each of the PIXI™ ports can be configured either to be the general purpose input or general
purpose output pin (GPI/GPO).
When set as the GPI pin, the programmable threshold can be set by its data register, from 0 up to
the AVDD voltage. The events like rising edges, falling edges or both can be sensed this way,
generating an interrupt.
A GPO pin can have a programmed HIGH logic level, up to four times of the DAC referent
voltage. The host can set the logic state of GPO-configured ports through the corresponding
GPO data registers.
By combining GPI and GPO configured ports, unidirectional and bidirectional level translator
paths can be formed, allowing all kinds of level shifters to be built. Bidirectional level translators
are built using adjacent pairs of pins and are meant to work as the open drain drivers, so the pullup resistors should be used to achieve proper voltage levels.
Analog Switch Operation Mode
Two adjacent PIXI™ ports can form an analog switch with the internal resistance of 60Ω, which
is controlled in two ways:
The signal flow through the two adjacent ports can be controlled by any other GPI PIXI™ port,
that is used as the switch.
The internal switching PIXI™ port is programmed to be permanent ON until that port is set to a
high‐impedance mode by the host controller.
Temperature sensors
The MAX11300 device also features two external sensors and one internal sensor, covering the
range from -40°C to +150°C with a good accuracy of ±1˚C. The external sensor can be a simple
diode-connected NPN transistor such as 2N3904, which can be used to measure the die
temperature of some other integrated circuits. The MAX11300 device also features the parasitic
resistance cancellation mode, for the connected temperature sensing element. Temperature can
be read from the temperature registers, with the 0.125°C per LSB value.
Other features
There are several other useful features on the MAX11300 device, such as the advanced interrupt
management that triggers an interrupt for many various events. Interrupts can also be masked,
allowing only the desired interrupts to affect the INT pin state of the click.
The separate pins for the analog GND and digital GND contribute to the signal quality,
especially when it comes to mixed-signal applications, where analog signal paths can easily be
influenced by the digital signal interferences. Features such as the Burst Transaction Address
Incrementing Modes, simplify the firmware development. While using the simple address
incrementing mode, the initial register address pointer will keep incrementing automatically after
each read/write cycle, as long as the device stays asserted by the CS pin and the serial clock
keeps running. The contextual incrementing mode works similar to the previous mode, with the
added ability to loop back to the initial start address, after one group of registers has been cycled
through. The contextual incrementing mode works only for DAC and ADC configured port
registers. For more information about the registers, please refer to the datasheet of the
MAX11300.
Specifications
Type
ADC,DAC
Best suited for applications that demand a mixture of several analog and digital
Applications functions, such as monitoring and adjusting the bias on the power amplifiers, digital level
shifters, automatic fan speed controllers, etc.
On‐board
modules
Maxim Integrated MAX11300
Maxim Integrated proprietary PIXI™ technology featuring versatile routing of all of the 20
Key Features PIXI™ ports, allowing realization of many different mixed signal applications with a single
IC, wide range of input and output voltages, both bipolar and unipolar.
Interface
GPIO,SPI
Input Voltage 3.3V or 5V
Click board
size
L (57.15 x 25.4 mm)
Pinout diagram
This table shows how the pinout on PIXI™ click corresponds to the pinout on the mikroBUS™
socket (the latter shown in the two middle columns).
Notes
Pin
Pin
Notes
NC
1
AN
PWM
16
CNV
ADC trigger control
NC
2
RST
INT
15
INT
Interrupt output
Chip select
CS
3
CS
TX
14
NC
SPI clock
SCK
4
SCK
RX
13
NC
SPI data output
SDO
5
MISO
SCL
12
NC
SPI data input
SDI
6
MOSI
SDA
11
NC
Power supply
+3.3V
7
3.3V
5V
10
+5V
Power supply
Ground
GND
8
GND
GND
9
GND
Ground
PIXI™ click electrical specifications
Description
Min
Typ
Max
Unit
Analog power supply voltage (AVDD)
4.75
5
5.25
V
Digital power supply voltage (DVDD)
2.50
3.3
5.50
V
External supply positive voltage AVDDIO
AVDD
15.75
V
External supply negative voltage AVSSIO
‐12
0
V
AVDD
24
V
External supply AVDDIO to AVSSIO
Note: For the correct setting of the AVDDIO and AVSSIO voltages, please refer to
the MAX11300 datasheet
Onboard settings and indicators
Label
Name
Default
Description
LD1
PWR
‐
Power LED indicator
HD1
Port
header
‐
20 pin PIXI™ ports connection
HD2
Port
header
‐
External power, diode temp sensors, analog, references, +5V on board and
common GND connection pins
JP1
Logic Sel
Left Logic voltage level selection, left position 3V3, right position 5V
Software Support
We provide a library for PIXI™ click on our LibStock page, as well as a demo application
(example), developed using MikroElektronika compilers. The demo can run on all the main
MikroElektronika development boards.
Library Description
Key functions
void pixi_writeRegister(uint8_t registerAddress , uint16_t registerData) -
Generic function for writing to registers.
uint16_t pixi_readRegister(uint8_t registerAddress)- Generic function for reading
from registers.
Examples Description
Simple example of LED blinking off all PIXI™ click pins, ports are configured by writing
messages to the appropriate registers via the SPI interface. The low-level communication is taken
care of inside the MikroElektronika functions. Registers can be easily accessed with two simple
functions:
pixi_writeRegister is the register writing function, which accepts two parameters. The first
parameter of the function is the 8bit register that needs to be written, while the second parameter
is the 16bit data that is written to the register provided with the first parameter. This function
does not return any value
pixi_readRegister is used to read the content of a certain register, which is forwarded as an 8bit
parameter. This function returns 16bit data which represents the contents of the register,
forwarded as the parameter.
The simple application example periodically sets all the GPIO pins to 5V and then to 0V, with
one second delay. More information about the registers and their functions can be found in
the MAX11300 datasheet.
void applicationTask()
{
pixi_writeRegister(0x0D,
pixi_writeRegister(0x0E,
Delay_ms(1000);
pixi_writeRegister(0x0D,
pixi_writeRegister(0x0E,
Delay_ms(1000);
}
0xFFFF); //setting all GPIO to 5V
0x000F);
0x0000); //setting all GPIO to 0V
0x0000);
The full application code, and ready to use projects can be found on our LibStock page.
Other mikroE Libraries used in the example:
SPI
Additional notes and information
Depending on the development board you are using, you may need USB UART click, USB
UART 2 click or RS232 click to connect to your PC, for development systems with no UART to
USB interface available on the board. The terminal available in all MikroElektronika compilers,
or any other terminal application of your choice, can be used to read the message.
https://www.mikroe.com/pixi‐click 12‐20‐17