Comtrol AT Commands - Manual (Page 40)

AT Commands for CX81801/CX06833/CX81300/CX06827 Modems Reference Manual
Conexant 102184B
3-14
**- Load Flash Memory
The AT** command allows users to customize modem firmware by uploading flash
memory firmware, NVRAM patch or internal SRAM patch.
Uploading flash memory firmware
The linear flash memory loader allows flash memory connected to the modem external
memory bus to be upgraded with revised modem firmware. This process transfers the
upgraded modem firmware from the host computer to the modem, which transfers the
data to the flash memory device. Uploading new firmware to the flash memory or is a
two-step process.
1. When the AT** command is issued, the modem firmware boot loader is invoked and
the user will first load a flash load module (FLM) into the modem's RAM. The data
transfer is done via an ASCII transfer. The FLM contains the programming
algorithm for the flash memory device being programmed and any messages that
may be sent during the load process.
2. The user will then load the new modem firmware which the FLM will then program
into the flash memory device. This transfer is done via ASCII transfer.
Procedure
1. Install in the modem a flash memory programmed with the modem firmware or a
blank flash memory.
2. Put the FLM (e.g. F45Aload.S37) and the new modem firmware file (e.g.
ACF31900V90P21FSH282621p3v9.s37) in an appropriate directory on the
computer's hard disk.
3. Configure the communications application program for a DTE rate of between 9600
bps and 115200 bps and RTS/CTS flow control. Note: When programming a blank
or corrupt flash device the modem’s automatic speed sensing function does not
operate and the modem defaults to 57600 bps.
4. Check the modem for response by typing AT.
5. Initiate the download process using the AT** command. The "Download flash
code…" message appears upon issuing the AT** command.
6. Perform an ASCII transfer of the FLM file (e.g., F45Aload.37) from the host
computer to the modem RAM using an industry standard communications software
or an equivalent process (ensure that all ASCII translation or pacing is turned off).
7. After the FLM has been loaded perform an AASCI upload of the new modem
firmware hex file (e.g., ACF31900V90P21FSH282621p3v9.s37) from the host
computer to the modem RAM using industry standard communications software or
an equivalent process.
8. The messages described in Table 3-1 may occur during the uploading process: