Reference Design
Mini-Z® USB Design Board
RD003002-0814
Overview
Zilog’s Mini-Z® USB Design Board provides a reference design to incorporate USB host
and peripheral functionality with Zilog’s portfolio of Mini-Z® modules. Its hardware
design uses a Max3421E USB transceiver to provide an interface to the USB communications with supporting power-limiting and connection circuitry. The design also incorporates a Secure Digital (SD) card using its SPI interface. The Mini-Z® USB Design Board
firmware includes host functionality for USB mass storage devices and Secure Digital
(SD) card support.
The Mini-Z® USB Design Board includes all of the hardware necessary to develop prototypes and projects incorporating the host and peripheral functions on Zilog’s wide selection of MCUs.
The Mini-Z® USB Design Board, shown in Figure 1, is designed to be operated by either a
9V battery or an external power supply.
Figure 1. The Mini-Z USB Design Board
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Note: The source code file associated with this application note, RD0030-SC01, is available free
for download from the Zilog website. This source code has been tested with version 5.0.1 of
ZDS II for ZNEO MCUs. Subsequent releases of ZDS II may require you to modify the code
supplied with this application.
Mini-Z USB Design Board Features
The key features of the Mini-Z® USB Design Board are:
•
Low/full speed USB host capability
•
Secure Digital (SD) card
•
Full-speed USB peripheral capability
•
USB serial communications
Potential Applications
The Mini-Z® USB Design Board can be used to develop a number of applications; the
brief list below offers a few ideas.
•
Secure Digital-to-USB converter
•
Adding removable storage to Zilog MCU projects
•
Adding USB Human Interface Device (HID) input for Zilog MCU projects
Shell Application
This section describes how to install the USB Host Shell and become familiar with its
commands.
Installing the Shell Application
Every module in Zilog’s Mini-Z® product mix is preloaded with a boot loader and control
shell. The shell application provides access to the module and to the design board that the
module attaches to.
Observe the following brief procedure to install the shell application.
1. Connect the USB cable (A male to Mini-B male, provided in your kit) from the PC to
the USB Design Board’s Mini-USB port. This Mini-USB port is located adjacent to
the reset switch on the opposite side of the USB-A and USB-B connectors, and is
labeled CONSOLE.
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2. Launch a terminal emulation program (such as HyperTerminal or TeraTerm) and
establish a connection to the Mini-Z® USB Design Board. The terminal application’s
communication settings should reflect the following values:
– 57600 baud rate
– 8 data bits
– No parity
– 1 stop bit
– No flow control
Note: This document assumes HyperTerminal to be the selected terminal emulation program.
3. Connect the Mini-Z® USB Design Board to the appropriate power source. When
power is applied, the following command prompt should appear on your terminal:
Z16Mini-Z>
Note: This Z16Mini-Z> prompt will appear if you are working with Zilog’s Mini-Z® ZNEO 28Pin Module. If you are working with Zilog’s Mini-Z® WLAN Module, you’ll instead see
this prompt portrayed as WLANMini-Z>. With the Mini-Z® Z-PAN® 28-Pin Module, this
prompt will appear as BTMini-Z>.
4. Enter the following command in the terminal console:
Flashapp
5. Press the Enter key. The console will prompt you to transfer a hex file. From the
Transfer menu in HyperTerminal, select Send Text File... (no modem protocol).
6. The Send Text File dialog will appear in Windows. In this dialog, navigate to and
select the USBHost_app.hex file, and click OK to flash the code to the Module. You
may be prompted to change the Files of Type selection to All files (*.*) at the bottom
of the Send Text File window.
7. After the Module has been flashed, the console will return to the command prompt.
Enter the following command to execute the application and start the USB host:
Execapp
Installation of the shell application is now complete. However, bear in mind that the next
time you power on the Mini-Z® USB Design Board, you must enter the Execapp command to once again execute the application and be able to have the USB Mini-Z® commands available to you. For additional details about this shell application, see the Mini-Z
Shell and Flash Loader Reference Manual (RM0061).
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USB Host Shell Application Commands
The USB Host Shell application provides the ability to access USB mass storage devices
(using FAT16/FAT32 file systems) and SD/MMC cards from the shell.
Drives are numbered (1,2, etc.) and are dynamic. Directories are referenced with a diagonal character ("/").
Table 1. Mini-Z USB Design Board Shell Command Description
Command
Description
Usage Example
List
Lists the drives that are currently
accessible.
Z16MiniZ>list
Drive 1: SD Card Total Size: 7757824K -FAT32
Drive 2: USB Drive Total Size: 1004031K -FAT32
Total Drives Found: 2
ChgDrive
Changes the default drive.
Z16MiniZ>chgdrive 2:
Drive changed.
Dir
Lists the directories for the drive. By
specifying the drive number followed
by a colon, you can get a directory
listing of the non default drive. You
can also specify a subfolder to get a
listing of the sub folder.
Z16MiniZ>dir
Drive 1 Directory ./
UNDERW~1.AVI 1316579328
UNDERW~2.AVI 1268234240
UNDERW~3.AVI 1013458944
FFDSHO~1.EXE 4560237
INSTAC~1.EXE 1645248
EXTACC~1.TXT 54
Total Files 6
Total Directories 0
Optional usage:
Z16MiniZ>dir 2:smrtntky
Drive 2 Directory smrtntky
..
< dir >
DEVICE
< dir >
WSETTING.WFC 803
MESSAGEB.TXT 285
FCW .ICO
22486
WSETTING.TXT 628
Total Files 4
Total Directories 2
Copy
Copies a specified file. No wild cards
are supported. You can copy
between drives by specifying drive
numbers.
Z16MiniZ>copy EXTACC~1.txt Mytxt.txt
Copying...Total bytes transferred: 54
Optional Usage:
Z16MiniZ>copy 2:hello.asp 1:
Copying...Total bytes transferred: 2824
Del
Allows the ability to delete a file from Z16MiniZ>del mytxt.txt
the drive.
Deleting file...
File: mytxt.txt has been deleted.
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Table 1. Mini-Z USB Design Board Shell Command Description (Continued)
Command
Description
Usage Example
CD
Allows the ability to change
Z16MiniZ>cd 2:smrtntky
directories within the drive. By
Directory changed.
specifying the drive number followed
by a colon, you can change the
directory on the other drive. The
directory location remains until either
the drive is removed or the CD
command is issued.
Type
Displays the specified text file on the Z16MiniZ>type test.txt
console. You can press Ctrl-C to stop
the display.
Hello
A test text file.
Z16MiniZ>
Dump
Displays the bytes of the file in
hexadecimal format. You can press
Ctrl-C to stop the display.
Z16MiniZ>dump test.txt
0x48 0x65 0x6C 0x6C 0x6F 0x20 0x0D 0x0A 0x54
0x68 0x69 0x73 0x20 0x69 0x73 0x20
0x61 0x20 0x74 0x65 0x73 0x74 0x20 0x74 0x65
0x78 0x74 0x20 0x66 0x69 0x6C 0x65
0x2E 0x0D 0x0A
Z16MiniZ>
Technology
This section discusses the technology of the Universal Serial Bus as well as SD card technology, its file systems, and hardware.
USB
The Universal Serial Bus (USB) is a host-controlled bus. There can only be one host per
bus, but up to 127 devices. The devices are connected in a tiered-star topology. In USB 2.0
and below, all communications are host driven, including interrupt transfers that have to
wait for the host to poll the device. (NOTE: The Mini-Z USB Design Board is USB 2.0
compatible, so we are not addressing USB 3.0). The communications are handled via
transactions with several layers of protocols. Each USB transaction consists of a Token
packet, data packet (optional) and a status packet (acknowledgement/error correction).
There is also the Start of Frame Packet that is sent by the host at regular intervals, for synchronization, which the MAX3421E takes care of, so it will not be discussed.
There are four different types of transfers that are defined in the USB protocol. They are:
Control Transfers. Used for command and status operations.
Isochronous Transfers. Transfers that are continuous at a specific rate
Interrupt Transfers. Small packets that are queried for at specific intervals
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Bulk Transfers. Used for large data that is not time dependent, such as burst data.
Because a host cannot detect which device has been plugged into the USB port, the USB
protocol has defined how a device must report which type of device it is. A device will
therefore use descriptors which the host can retrieve through a control transfer mechanism. These descriptors are diagrammed in Figure 2.
Figure 2. USB Descriptors
Each device can have only one Device descriptor, and each Device descriptor includes the
following device information:
•
USB Version supported
•
Device Class (if 0, then located in the interface Descriptors)
•
Device SubClass
•
Device Protocol
•
Max Packet size
•
Vendor ID
•
Product ID
•
Device Release Number
•
Manufacture String Descriptor Index
•
Product String Descriptor Index
•
Serial Number String Descriptor Index
•
Number of Configurations
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Each device descriptor can have one or more Configuration descriptors, which define the
power usage and the number of interfaces for a particular configuration. The host must
activate the configuration that it will use, and is only allowed one active configuration at a
time. Configuration descriptors include the following information:
•
Number of interfaces
•
Configuration string descriptor index
•
Power attributes:
– Self-powered
– Bus-powered
– Remote wakeup
•
Maximum power (in 2 mA units)
Each configuration descriptor can have one or more Interface descriptor, which is a grouping of endpoints that provides a feature for the device. The host may enable as many of
these interfaces as is appropriate. An Interface descriptor includes the following information:
•
Number of endpoints
•
Interface class code (USB class codes)
•
Interface subclass code (USB subclass codes)
•
Interface protocol (USB protocol code)
•
Interface string descriptor index
Each interface descriptor can have one or more Endpoints descriptors, which are used to
specify the type of transfer, direction, and polling interval for the host to use. There is a
special endpoint, Endpoint 0, that has no descriptor; this particular endpoint is the default
control endpoint and is always active. Endpoints descriptors include the following information:
•
Endpoint address (includes a direction bit)
•
Endpoint attributes (includes transfer type, synchronization info, endpoint type)
•
Maximum packet size
•
Polling interval (in frame counts)
Not shown in Figure 2 are String descriptors, which can include strings such as manufacturer, product name, etc., and can be accessed by an index of all descriptors. These String
descriptors allow for different spoken languages.
For a host to acquire device information and configure a device for operation, communication starts with a set-up packet on Endpoint 0. This set-up packet includes information
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such as the type, direction, recipient (device, interface, endpoint), request, and associated
data necessary for the request. There are seven standard device requests:
•
Get_Status
•
Clear_Feature
•
Set_Feature
•
Set_Address
•
Get_Descriptor
•
Set_Descriptor
•
Get_Configuration
•
Set_Configuration
When a Get_Descriptor request is issued for the Configuration descriptor, the Interface
and Endpoints descriptors are included in the response. The typical sequence for acquiring
information is:
1. Retrieve a Device descriptor to determine the number of Configuration descriptors.
2. Set a unique bus address for the device.
3. For each configuration:
a. Retrieve Configuration descriptors.
b. Parse Interface and Endpoints descriptors from the reply.
After the descriptors have been processed, the host knows what the device is and what its
function is. If the device is something the host can support, the host will select and activate
an appropriate configuration and start interfacing with the endpoints.
Device communication is based on logical channels or pipes. These pipes are logical connections between a host and its endpoints; they can be opened or closed. Endpoints are
part of the device, so they always exist. A device can have up to 32 endpoints. There are
two types of endpoints: stream and message (control). Message endpoints are bidirectional
and are used for control transfers. The stream endpoint is a unidirectional pipe.
The Mini-Z USB Design Board’s firmware currently supports only USB mass storage
devices. These types of storage devices use bulk transfer endpoints to transfer data in and
out via the SCSI protocol. The SCSI protocol can support up to seven Luns (different
disks) per device, though typically there is only one Lun on a USB device.
To transfer data on a mass storage device, the mass storage unit must also be initialized.
This initialization includes identifying how many Luns are available on the device, determining the capacity of the drive, and waiting for it to be ready.
All communication with the SCSI includes a header packet of 31 bytes (i.e., a Command
Block Wrapper, or CBW) followed by the data, and completed with a status packet of 13
bytes (i.e., a Command Status Wrapper, or CSW). All of these packets are sent/received on
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the bulk transport of the associated endpoints. There only a limited set of SCSI commands
that are required to be supported for USB mass storage devices. The typical commands
used for mass storage devices are:
GetReadyStatus. Identify when the SCSI subsystem of the device is ready
GetCapacity. Returns the capacity of the drive
Read10. Bulk Read Block command
Write10. Bulk Write Block command
There are two USB application-specific commands that are supported and sent through the
control pipe:
RequestLUN. Request the Lun count (although some devices do not support)
MSBulkReset. Resets the SCSI subsystem on the Bulk endpoint
SD Card
A Secure Digital (SD) card is a nonvolatile memory card developed by Toshiba, Matsushita Electric and SanDisk from the MultiMedia Card specifications. An SD card offers features such as digital rights management (DRM), higher density, and faster speeds. The SD
Card Association maintains the Secure Digital Standard.
There are currently three types of SD cards:
SDSC. Standard, a maximum of 2 GB capacity
SDHC. High Capacity, a maximum of 32 GB
SDXC. eXtended Capacity, a maximum of 2 TB
The Mini-Z USB Design Board only supports SDSC and SDHC cards, as well as MMC
cards.
An SD card can operate in two modes: SD Mode and SPI Mode. The Mini-Z USB Design
Board employs the 4-wire SPI Mode. The host communicates with the SD card with commands to identify and control the cards. The commands include information commands,
configuration commands and reading/writing commands. SD cards are block-addressable
storage devices that require read and writes to be in full blocks (typically 512 bytes). The
Mini-Z USB Design Board communicates with the SD cards in SPI Mode.
To access an SD card, an initialization sequence must be followed to both determine the
type of card that it is (SDSC, SDHC or MMC), then set the card to be in a ready state to
receive commands. After this initialization sequence is completed, the host can read and
write blocks.
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File Systems
The file systems supported with the Mini-Z USB Design Board firmware is the FAT16 and
FAT32. These file systems contain the Master Boot Record, which contains the partition
information, and a Volume Boot Record, which contains the information for the volume.
Some devices may only have a Volume Boot Record on the first sector (sector 0) instead
of a Master Boot Record.
The Volume Boot Record contains all of the information for accessing the partition (volume), including the size of the sector, the number of sectors in a cluster, the maximum number of clusters, the location for the File Allocation Tables, the type of FAT being used, etc.
The FAT file system breaks up a space into clusters, and clusters are further broken into sectors. A sector will typically be 512 bytes (although there are new standards that increase sector size to handle more space). The File Allocation Table keeps track of all of the clusters
that are being used and the chain of clusters for files that exceed a single cluster.
There is a specific area in a FAT file system that stores directory information. On a FAT16
file system, the Directory sectors occur right before the start of the clusters; on a FAT32
system, the Directory entries are allocated clusters. Each Directory entry is 32 bytes in
length; an entry contains information about a file such as its attributes, starting cluster,
size, 8.3 filename, etc. Additionally, long file name (LFN) directory entries allow long file
names. These are additional Directory entries that contain double-byte characters describing a name as well as the original directory entry with an 8.3 filename. LFNs retain a specific attribute that serves to identify the type of entry it is.
The Mini-Z USB Design Board firmware only supports DOS names, not Long File
Names. To allow for long file name entries, all entries that contain the LFN attribute
(0x0F) are skipped.
Hardware
The Mini-Z USB Design Board hardware design uses a Max3421E USB transceiver to
provide an interface to USB communications. The MAX3421E contains the digital logic
and analog circuitry necessary to implement a full-speed USB peripheral or a full-/lowspeed host compliant to USB Specifications Revision 2.0. An internal serial interface
engine handles the low-level USB protocol details such as error checking, bus retries, and
frame packets. The interface to the MAX3421E is the SPI interface.
This hardware includes both circuitry for peripheral implementation, as well as the host
(though the system can only be in either host or peripheral mode at any given time). The
host side also incorporates a current limit switch (MAX1776) to limit current draw from
the Host port, thereby allowing power to be supplied to any USB devices without drawing
excess power.
The SD card circuitry includes an analog circuit to only apply power to the SD card when
there is a card detected. This circuit is also monitored by the MCU to determine when a
user adds or removes an SD card.
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Electrical Specifications
Stresses greater than those listed in Table 2 may cause permanent damage to the device.
These ratings are stress ratings only. Operation of the device at any condition outside those
indicated in the operational sections of these specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods affects device reliability. For
improved reliability, unused inputs must be tied to one of the supply voltages (VDD or
VSS).
Table 2 describes the electrical characteristics of the Mini-Z USB Design Board and
reflects all available data as a result of testing prior to qualification and characterization.
As such, the data presented in Table 2 is subject to change.
Table 2. Electrical Specifications for the Mini-Z USB Design Board
Parameter
Min
Max
Units
Notes
VIN range
5.5
17
Volts
Module-dependent.
Max voltage range, all other pins
–0.3
5.5
Volts
I/O pins and Reset.
Max current for I/O pin connection points
–25
25
Milliamps
(mA)
1
Amps
Max VIN current
VOUT USB Host
4.8
5.2
Volts
Ambient temperature
–40
105
Degrees
Celsius
Storage temperature
–65
150
Degrees
Celsius
Table 3 describes the electrical characteristics of the Mini-Z USB Design Board’s terminal
blocks.
Table 3. Terminal Block Specifications
Rated Voltage
150 Volts
Rated Current
6 Amps
Wire Size
AWG 28-16
Test Voltage
2.0K volts
Rated Torque/Screw Size
0.4 Nm/M2
Wire:
Max rated cross section:
Solid Wire
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Table 3. Terminal Block Specifications
Stranded Wire
1.5mm
Stranded wire with
Ferrules
.75mm
Stripped Length
5.5mm
Packaging
Figure 3 displays an assembly diagram of the Mini-Z USB Design Board.
Figure 3. Mini-Z USB Design Board Assembly Diagram
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Bill of Materials
Figure 4 lists all parts that comprise the Mini-Z USB Design Board.
ITEM # Designator
1
C1
2
C2
3
C3, C4, C5, C6
4
C7, C10, C13
5
C8, C9
6
C11
7
C12
8
D1
9
J1
10 J2
11 J3
12 J4
13 J5
14 L1
15 LED1
16 Q1
17 R1, R2, R6, R9, R10
18 R3, R4, R5
19 R7
20 R8
21 R11, R12
22 SW1
23 GND
24 U1
25 U2 --Dip Socket-26 U3
27 U4
28 U5
29 VR1
30 Y1
Value
Footprint
Description
Manufacturer
Mfg. Part Number
10uF 6.3V
4.7uF
.1uF
1uF
18pF
10uF
100uF 10V
SS3P3-M3
Mini B
SD Card
POWER
USB B 4PIN
USB Type A
10uH
GRN
DMP2215L
100K
56K
1K
2K
33
RESET
TP
FT232RL
ZNEO STAMP
SN74LVC2GU04
MAX3421E
MAX1776
REG102NA-3.3
12Mhz Crystal
CAP 1206
CAP 1206
0603
0603
0603
CAP 1206
CAP ELECT F55 7.2x6.6mm
DO-214AA_SMB
USB MiniB TH
SD CARD TE 2041021
TermBlock2 3.5mm
USB_B
USB Type A
1206
LED0603
SOT23 DMP2215L
0603
0603
0603
0603
0603
SW SMD 6.8x3.7MM
TEST POINT 063
SSOP28
DIP28x.6
SOT23-6
TQFP32L
MAXu8
SOT23-5L
HCM49
CAP TANT
CAP 4.7uF 16V A
CAP CER 25V 0603
CAP 1uF 16V 0603
CAP CER 18pF 50V 0603
TANT 16V
CAP 100uF 10V 6.3mmDia SMD
Schottsky Diode (3A/30V)
USB MiniB 5 ThroughHoe
SD Card holder
TERM BLOCK 125V 6A
USB B 4 PIN
USB Type A Connector
100 Ohm 3A
LED GRN 2.03V 10mA 0603
FET PCH 2V 2.7A SOT23
RES 100K 0603
RES 56K 1% 1/10W
RES 1K 0603
RES 2.0K 1%
RES 33 Ohm 0603
SW PB SMD 6.1x3.7mm
Test Point
IC USB TO SERIAL UART SSOP28
ZNEO STAMP28 SOCKET
Inverter Dual Sot23-6
USB Transciever
Buck Converter with Current Limit
VOLT REG 3.3V 400mA SOT23-5
AVX
AVX
Murata
Murata
Murata
ROHM
United ChemiCon
Vishay
WURTH ELECT
3M
On Shore Tech
TAJA106K006RN
GRM188F51E104ZA01D
GRM188F51C105ZA01D
GRM1885C1H180JA01D
TCA1C106M8R
EMVA100ADA101MF55G
SS3P3-M3/84A
651005136521
ED555/2DS
Adam Tech
Panasonic
Diodes Inc
LNJ314G83RA
DMP2215L-7
Vishay
CRCW06031K00FKEA
Yageo
C&K
Keystone Elect
FTDI
RC0603FR-0733RL
PTS635SK25SMTR LFS
5011
FT232RL-REEL
TI
Maxim
Maxim
TI
ABRACON
SN74LVC2GU04DBVR
REG102NA-3.3/250
Figure 4. Mini-Z USB Design Board Parts List
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Mechanical Profile
Figure 5 displays the dimensions of the Mini-Z USB Design Board.
Figure 5. Mini-Z USB Design Board Dimensions
Kit Contents
The Mini-Z USB Design Board Kit contains the following items:
•
Mini-Z ZNEO 28-Pin Module
•
Mini-Z USB Design Board
•
USB SmartCable
•
Mini-Z to standard debug adapter
•
USB cable (A male to Mini-B male)
•
DIP Package Extractor
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Ordering Information
The products associated with the Mini-Z USB Design Board are available individually or
as a kit and can be purchased from the Zilog Store – simply click the Store Product IDs
listed in Table 4.
Table 4. Mini-Z USB Design Board Ordering Information
Part Number
Description
Store Product ID
Z16F28UB100ZRDG
Mini-Z USB Design Board
RD10024
Z16F28UB100KITG
Mini-Z USB Design Board Kit
RD10025
Z16F2800100MODG
Mini-Z ZNEO 28-Pin Module
RD10002
Z16F28WF100MODG
Mini-Z WLAN 28-Pin Module
RD10003
Z16F28ZP100MODG
Mini-Z Z-PAN 28-Pin Module
RD10008
Related Documentation
The documents associated with the Mini-Z USB Design Board are listed in Table 5, and
supporting manufacturers’ documentation is listed in Table 6. Each of these documents
can be obtained from the Zilog website (except where noted in Table 6) by clicking the
link associated with its Document Number.
Table 5. Mini-Z USB Design Board Documentation
Document
Number
Description
RD0030
This Mini-Z USB Design Board Reference Design document.
RD0030-SC01
Source code for the Mini-Z USB Design Board Reference Design.
RD0006
Mini-Z ZNEO 28-Pin Module Reference Design document.
RD0006-SC01
Mini-Z Library.
RM0061
Mini-Z Shell and Flash Loader Reference Manual.
PS0220
ZNEO Z16F Series Product Specification.
UM0188
ZNEO CPU Core User Manual.
UM0181
USB Smart Cable User Manual.
Table 6. Supporting Manufacturers’ Documentation
Document
Number
Description
MAX3124E
MAX3421E Datasheet.
MAX1776
MAX1776 Current Limit Step-Down Converter.
SD Card Spec
SD Specifications Part 1 Physical Layer Simplified Specification.
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Table 6. Supporting Manufacturers’ Documentation (Continued)
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Document
Number
Description
USB 2.0 Spec
USB 2.0 Specifications.
USBmasbulk
USB Mass Storage Class Bulk-Only Transport Specification.
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Appendix A. Schematic Diagram
Figure 6 shows a schematic diagram of the Mini-Z USB Design Board.
VCC_5V
VIN_5.5-15V
U1
FT232RL
GND
1
VIN VOUT
RESET
VCC_5V
SOUT
SIN
RTS
U3
1
2
3
6
5
4
1A
1Y
GND VCC
2A
2Y
SN74LVC2GU04
GND
TP1
TestPoint
TP2
TestPoint
TP3
3
U2
1
2
3
4
5
6
7
8
9
10
11
12
13
14
PA4/RX
PA5/TX
PA3/RTS
VSS
PB0
PB1
PB2
PB3
PD0
PD1
PA7
PA6
PB7
PB6
VIN
VSS
RES
VCC
PC7
PC6
PC5
PC4
PC3
PC2
PC1
PC0
PD7
PD2
28
27
26
25
24
23
22
21
20
19
18
17
16
15
EN
GND
NR
VCC_3.3V
5
+
4
C3
.1uF
C1
10uF 6.3V
PC7_USBInt
VCC_3.3V
C6
C7
R1
100K
ZNEO STAMP MODULE SOCKET
8
7
6
5
4
3
2
1
R6
100K
TestPoint
TP5
Q1
DMP2215L
R7
GND
R8
2K
TestPoint
TP9
LED1
GRN
TestPoint
VCC_3.3V
R10
100K
TP10
TestPoint
9
10
11
12
13
14
15
16
1K
TestPoint
TP7
TestPoint
TP8
1uF
GND
U4
MAX3421E
VCC_3.3V
TestPoint
TP4
TestPoint
TP6
VCC_3.3V
VCC_3.3V
R2 R3 R4 R5 .1uF
100K 56K 56K 56K
PD2
GPO4
GPO3
GPO2
GPO1
GPO0
GND
VL
GPI7
GND
GPO5
GPO6
GP07
RES
SCLK
SS
MISO
MOSI
GPI6
GPI5
GPI4
GPI3
GPI2
GPI1
GPI0
XO
Y1
C8
18pF
PC7_USBInt
J2
SD Card
32
31
30
29
28
27
26
25
2
R12
33
U5
J3
POWER
5
C11
10uF
2
PD2
6
7
8
GND
IN
LX
ILIM2 ILIM
SHDN GND
Out
FB
4
3
2
1
10uH
D1
SS3P3-M3
VCC
C10
1uF
L1
GND
C12
100uF 10V
C13
1uF
MAX1776
GND
GND
J5
URL TypeA
Figure 6. Mini-Z USB Design Board Schematics
RD003002-0814
R11
33
1
2
3
4
1
1
12Mhz Crystal
GND
Note: Inductor/Cap/Diode all need to as close together as possible with LX pin GND
VIN_5.5-15V
Page 17 of 25
VCC
DD+
GND
C5
.1uF
VR1
REG102NA-3.3
SW1
GPX
INT
GND
DD+
VBCOMP
VCC
XI
3.3V
5
1
3
11
2
9
10
6
23
22
13
14
12
24
17
18
19
20
21
22
23
24
C2
4.7uF
RXD
TXD
RTS
CTS
DTR
DSR
DCD
RI
CBUS0
CBUS1
CBUS2
CBUS3
CBUS4
NC
1
2
3
4
+
VCC
USBDM
USBDP
VCCIO
NC
RESET
OSCI
OSCO
3V3OUT
TEST
AGND
GND
GND
GND
VBus
DD+
Gnd
C4
.1uF
20
16
15
4
8
19
27
28
17
26
25
18
21
7
2
DD+
9
1
2
3
4
5
6
7
8
CD
WP
1
2
3
4
5
DAT2/NC
DAT3/CS
CMD/MOS1
GND
VDD
CLK/SCLK
GND
DAT0/MISO
DAT1/NC
CardDetect
WriteProtect
ni B
Mini-Z® USB Design Board
Reference Design
J4
USB B 4PIN
5
6
GND
Mini-Z® USB Design Board
Reference Design
Appendix B. Firmware Layout
The firmware consists of a layered approach to isolating the hardware from its interfaces.
This approach, as described in Tables 7 and 8, allows a developer to add/remove hardware
and to add/remove volume support.
Table 7. Upper Layer Firmware Programs
Program
Description
MAIN.C
This file contains the application initialization and command handling routines.
The InitApplication function is the application entry code for the Mini-Z console
to call when the user executes the application. This function initializes specific
required ports and initializes the hardware buses to be used. The command
handling function is next registered with the console; additionally, the callback
function (Monitor) is called every 300 ms. Ports used by the application that
are not available for other commands are then added to the exclusion list; the
routine then exits, returning control to the console. Every 300 ms, the Monitor
function is called by the console. This function checks to see if an SD card or
USB device has been added or removed. If a device has been added, the
device is initialized; if a device has been removed, the device is removed from
the list. When a command is entered, the console passes control to the
command-handling routine that is registered to perform the command.
USBCMDS.C
This routine contains the implementation for the different commands that are
added to the console to access the Mini-Z USB Design Board.
FILEIO.C
This file provides the implementation for standard file I/O functions such as
fopen, fclose, fread, fwrite, etc.
DIRIO.C
This file provides the implementation for Directory access for drives.
FAT.C
This file provides the implementation for FAT16 and FAT32 file allocation
tables.
DRIVE.C
This file contains the implementation to segregate volumes into logical drives.
Table 8. Lower Layer Firmware Programs
Program
Description
DEVICE.C
This file provides an interface to the upper layers for reading and writing
devices, regardless of the hardware. As a result, the upper layers can perform
requests for reads and writes without having to recognize the hardware.
USBMASSSTORAGE.C
This file contains the mass storage handing routine for the USB devices. USB
mass storage devices use a SCSI interface to retrieve data.
USBHOST.C
This file contains the USB host functionality for the MAX3721E device with
USB protocols. Control and endpoint communications are provided for the
USB device as well as to monitor the bus for the insertion and removal of USB
devices.
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Mini-Z® USB Design Board
Reference Design
Table 8. Lower Layer Firmware Programs (Continued)
Program
Description
SD.C
This file contains the implementation of the interface routine to the SD card; it
includes the initialization, reading and writing routines for the SD card.
SPI.C
This file contains the interface to the SPI bus on the ZNEO microcontroller.
The SPI bus is shared between the USB transceiver hardware and the SD
card. These devices are transaction-oriented devices, and will track if the SPI
bus is in use by the other device, thereby completing the transaction on one
device before starting a transaction on the other device. The low-level access
routine to the SD card and USB transceiver can also be found in this file.
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Mini-Z® USB Design Board
Reference Design
Appendix C. Flow Charts
This appendix displays flow charts that diagram the major functions of the Mini-Z USB
Design Board. Figure 7 illustrates the flow of the application initialization routine.
Entry
N
Is Shell Version
high enough?
Y
Set USB power pin
for output (PD2)
Initialize SPI bus
and Ports for USB/
SD card
Initialize USB host
Register
Command handler
with console
Register monitor
for callback every
300ms
Set bitmap
exclusion for ports
in use
End
Figure 7. Application Initialization Routine
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Mini-Z® USB Design Board
Reference Design
Figure 8 illustrates the flow of the monitoring routine.
Start
Has SD card
status changed?
Y
Inserted card?
N
Initialize SD card
Add Device
Get Drive
Parameters
Enumerate USB
device
Add Device
Y
New USB
device
Detected?
N
Get Drive
Parameters
USB device
Removed?
Y
Remove Drive
information
N
Remove Device
End
Figure 8. Monitoring Routine
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Mini-Z® USB Design Board
Reference Design
Figure 9 illustrates the flow of the SD Card initialization routine.
Set SPI bus to 400K
Clock out 75 cycles
Send CMD 0
Send CMD 8
Received
Legal?
N
Send CMD55 +
Send ACMD41
Y
Send CMD55 +
Send ACMD41
Received
Legal?
N
Send Cmd1
Y
Received
Legal?
N
Return
Error
Received
busy?
Y
Y
Received
Busy?
Y
N
Send CMD16
(set block size)
N
Send CMD58
Record
MMC type
Retrieve
Card type
from
Response
Set SPI bus to full
speed
End
Figure 9. SD Card Initialization Routine
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Mini-Z® USB Design Board
Reference Design
Figure 10 illustrates the flow of the USB device enumeration routine.
Reset USB Bus
Get Initial Device
Descriptor
Assign Unique
Address
Get full Device
Descriptor
All
Configurations
processed?
Y
N
Get Configuration
Descriptor
Y
All interfaces
processed?
N
Parse Interface
Descriptor
USB Class
Handled?
N
Y
Parse Endpoint
Descriptors
Save
Interface
information
Set Selected
Configuration
End
Figure 10. USB Device Enumeration Routine
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Mini-Z® USB Design Board
Reference Design
Figure 11 illustrates the flow of the drive information routine.
Read Sector 0
Is Master boot
Record?
N
Y
Parse Partition
information
Read Volume
Sector
N
Is Volume Boot
Record?
Y
N
Is Volume
FAT16 or
FAT32?
Y
Return Error Unsupported File
system
Parse and
Save
Volume
Information
End
Figure 11. Drive Information Routine
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Mini-Z® USB Design Board
Reference Design
Customer Support
To learn more about this product, find additional documentation, get your technical questions answered or report issues, please contact esales@zilog.com.
Warning: DO NOT USE THIS PRODUCT IN LIFE SUPPORT SYSTEMS.
LIFE SUPPORT POLICY
ZILOG’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE
SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF
THE PRESIDENT AND GENERAL COUNSEL OF ZILOG CORPORATION.
As used herein
Life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b)
support or sustain life and whose failure to perform when properly used in accordance with instructions for
use provided in the labeling can be reasonably expected to result in a significant injury to the user. A
critical component is any component in a life support device or system whose failure to perform can be
reasonably expected to cause the failure of the life support device or system or to affect its safety or
effectiveness.
Document Disclaimer
©2014 Zilog, Inc. All rights reserved. Information in this publication concerning the devices, applications,
or technology described is intended to suggest possible uses and may be superseded. ZILOG, INC. DOES
NOT ASSUME LIABILITY FOR OR PROVIDE A REPRESENTATION OF ACCURACY OF THE
INFORMATION, DEVICES, OR TECHNOLOGY DESCRIBED IN THIS DOCUMENT. ZILOG ALSO
DOES NOT ASSUME LIABILITY FOR INTELLECTUAL PROPERTY INFRINGEMENT RELATED
IN ANY MANNER TO USE OF INFORMATION, DEVICES, OR TECHNOLOGY DESCRIBED
HEREIN OR OTHERWISE. The information contained within this document has been verified according
to the general principles of electrical and mechanical engineering.
ZNEO and Mini-Z are trademarks or registered trademarks of Zilog, Inc. All other product or service
names are the property of their respective owners. Zilog and Clare are divisions of IXYS Corporation.
RD003002-0814
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