Multi-Tech Systems Modem Module MT3334SMI - Manual (Page 68)

ModemModule Developer’s Guide
MT3334SMI 68
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 (see section 3.5)
[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 (see sections 3.2 - 3.4)
[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.
(see section 3.1)
[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 If bytes are programmed and verified.
\nERROR\r\n 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
2. Other supported boot code commands
2.1. ATI0 - returns 247
2.2. ATI1 - returns boot code version number MM.mm where
MM = unique code for each different platform that has boot code
mm = version number of boot code
2.3. AT*FI - when given in standard AT mode gives the boot code version (same as in section
2.2). See section 3.7.
3. Other programming concerns
3.1. The values programmed into Addresses 0000h, 0001h and 0002h should always be forced to
C3h 01h 00h (ie. JP 100h).
This is because the boot code starts at address 100h, while all normal modem code starts at
200h. By allowing 0000h to be programmed to a jump value other than 0100h, the boot code
would be bypassed and no further upgrades could occur.
3.2. Addresses 1E0000h through 1FFFFh should not be allowed to be programmed under normal
circumstances as this is the main body of the boot up code.