Datasheet

www.ti.com
Appendix F USB-MODEVM Protocol
F.1 Writing Scripts
A script is simply a text file that contains data to send to the serial control buses.
Each line in a script file is one command. No provision is made for extending lines beyond one line, except
for the > command. A line is terminated by a carriage return.
The first character of a line is the command. Commands are:
I Set interface bus to use
r Read from the serial control bus
w Write to the serial control bus
> Extend repeated write commands to lines below a w
# Comment
b Break
d Delay
f Wait for flag
The first command, I, sets the interface to use for the commands to follow. This command must be
followed by one of the following parameters:
i2cstd Standard mode I
2
C bus
i2cfast Fast mode I
2
C bus
spi8 SPI bus with 8-bit register addressing
spi16 SPI bus with 16-bit register addressing
gpio Use the USB-MODEVM GPIO capability
For example, if a fast mode I
2
C bus is to be used, the script begins with:
I i2cfast
A double-quoted string of characters following the b command can be added to provide information to the
user about each breakpoint. When the script is executed, the software's command handler halts as soon
as a breakpoint is detected and displays the string of characters within the double quotes.
The Wait for Flag command, f, reads a specified register and verifies if the bitmap provided with the
command matches the data being read. If the data does not match, the command handler retries for up to
200 times. This feature is useful when switching buffers in parts that support the adaptive filtering mode.
The command f syntax follows:
f [i2c address] [register] [D7][D6][D5][D4][D3][D2][D1][D0]
where 'i2c address' and 'register' are in hexadecimal format and 'D7' through 'D0' are in binary
format with values of 0, 1 or X for don't care.
Anything following a comment command # is ignored by the parser, provided that it is on the same line.
The delay command d allows the user to specify a time, in milliseconds, that the script pauses before
proceeding. The delay time is entered in decimal format.
A series of byte values follows either a read or write command. Each byte value is expressed in
hexadecimal, and each byte must be separated by a space. Commands are interpreted and sent to the
TAS1020B by the program using the protocol described in Section G1 (doesn't exist).
The first byte following an r (read) or w (write) command is the I
2
C slave address of the device (if I
2
C is
used) or the first data byte to write (if SPI is used—note that SPI interfaces are not standardized on
protocols, so the meaning of this byte varies with the device being addressed on the SPI bus). The
second byte is the starting register address that data will be written to (again, with I
2
C; SPI varies—see
Section G1 (doesn't exist) for additional information about what variations may be necessary for a
particular SPI mode). Following these two bytes are data, if writing; if reading, the third byte value is the
number of bytes to read, (expressed in hexadecimal).
34
USB-MODEVM Protocol SLAU331A–January 2011–Revised October 2012
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated