AX.25 Modem
CMX7031/CMX7041
7.3.2 FI Loading from Serial Memory
The FI must be converted into a format for the serial memory programmer (normally Intel Hex) and loaded
into the serial memory either by the host or an external programmer. The CMX7031/CMX7041 needs to
have the BOOTEN pins set to serial memory load, and then on power-on, or following a C-BUS General
Reset, the CMX7031/CMX7041 will automatically load the data from the serial memory without
intervention from the host controller.
BOOTEN2=0
BOOTEN1=1
Power-up / Reset CMX7031
Wait for C-BUS $C6 bit 0 to be set to 1
Verify Checksum values in $A9, $AA and
$B8, $B9
note: BOOTEN1 and
BOOTEN2 may be changed
at this point, if required
Send Device Activation Code hi to $C8
Wait for C-BUS $C6 bit 0 to be set to 1
Send Device Activation Code lo to $C8
Vdd
Wait for C-BUS $C6 bit 0 to be set to 1
CMX7031 is now ready for use
Jumper for
programming
serial memory
(if required)
BOOTEN1
BOOTEN2
Figure 8 FI Loading from Serial Memory
The CMX7031/CMX7041 has been designed to function with Atmel AT25HP512 serial EEPROM and the
2
AT25F512 flash EEPROM devices , however other manufacturers parts may also be suitable. The time
taken to load the FI is dependant on the Xtal frequency, with a 6.144MHz Xtal, it should load in less than 1
second.
2
Note that these two devices have slightly different addressing schemes. FI 4.x is compatible with both schemes.
2013 CML Microsystems Plc
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D/7031/7041_FI-4.x/5
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