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Chapter 9 – Firmware Upgrade Procedure
SocketModem Global MT5634SMI Developer’s Guide 72
Multi-Tech Systems, Inc. Flash Programming Protocol
Important:
When interacting with the boot code, it is possible to make the modem inoperable. Use extreme caution.
1. Programming the Modem
There are two ways to start flash programming a modem. It can be programmed
1. From “AT” mode
2. When the modem powers up.
Below is an example of how a modem is programmed.
DTE Modem Comments
AT*FS\r This effectively “restarts” the modem so that it enters the
boot code.
Handshake Sequence
M’s Many M’s are sent (10 milliseconds apart) at 19200 baud.
This is where the handshake starts if the modem is just
powered up.
U U is sent at 19200 baud if M’s are received within 100
milliseconds of power up. If the M’s are not received within
100 milliseconds, then the modem starts up normally. If the
AT*FS command is used, then you have 1 second
(1000mS) to perform the handshake.
D Sent at 19200 baud.
M M if can receive at 9600/19200/38400/57600/115200
I|J|K|L|M I if modem will be programmed at 9600
J if modem will be programmed at 19200
K if modem will be programmed at 38400
L if modem will be programmed at 57600
M if modem will be programmed at 115200
\r\nOK\r\n Modem is ready to be programmed
Program Sequence:
DTE Modem Comments
ATFLP\r Request to the modem to program
G Modem is ready for next program packet
[Length High] High byte of data packet length
[Length Low] Low byte of data packet length
Packet lengths can be up to 4096 bytes in size for most boot
code versions
[Address High] High byte of program address
[Address Middle] Middle byte of program address
[Address Low] Low byte of program address
Addresses are 3 byte values with a range of 00000h-
FFFFFh
[Data Bytes] These are the data bytes to be programmed at the address
specified above. They must be the same number of bytes
as specified above.
[Checksum] This checksum is generated by exclusive ORing together all
of the Data Bytes (do not include the Length or Address
bytes in that calculation).
\nOK\r\n
\nERROR\
r\n
If bytes are programmed and verified.
If verify fails or checksum is bad.
Retry the block 3 times on an ERROR.
…. ….
More of the above sequence until all the data bytes have
been sent to the modem.
ATFLEND\r This ends programming and restarts the modem.