AX.25 Modem
CMX7031/CMX7041
7.3.1 FI Loading from Host Controller
The FI can be included into the host controller software build and downloaded into the
CMX7031/CMX7041 at power-up over the C-BUS interface. The BOOTEN pins must be set to the C-BUS
load configuration, the CMX7031/CMX7041 powered up and placed into Program Mode, the data can then
be sent directly over the C-BUS to the CMX7031/CMX7041.
Each time the device is powered up its Function Image™ must first be loaded and then activated. These
two steps assign internal device resources and determine all device features. The device does not
operate until the Function Image™ is loaded and activated.
BOOTEN2=1
BOOTEN1=1
Power-up / Reset CMX7031
Send Start Block 1 Address (DB1_ptr) to C-BUS $B6
Send Block 1Length (DB1_len) to C-BUS $B7
Wait for C-BUS $C6 bit 0 to be set to 1
Send $0001 to C-BUS $C8
Wait for C-BUS $C6 bit 0 to be set to 1
Send next data to C-BUS $C8
Send Start Block 2 Address (DB2_ptr) to C-BUS $B6
Send Block 2 Length (DB2_len) to C-BUS $B7
Wait for C-BUS $C6 bit 0 to be set to 1
Send $0001 to C-BUS $C8
Wait for C-BUS $C6 bit 0 to be set to 1
Send next data to C-BUS $C8
Send Start Block 3 Address (ACTIVATE_ptr) to C-BUS $B6
Send Block 3 Length (ACTIVATE_len) to C-BUS $B7
Wait for C-BUS $C6 bit 0 to be set to 1
Send $0001 to C-BUS $C8
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
VDD
Send Device Activation Code lo to $C8
Wait for C-BUS $C6 bit 0 to be set to 1
BOOTEN1
BOOTEN2
CMX7031 is now ready for use
Figure 7 FI Loading from Host
The download time is limited by the clock frequency of the C-BUS, with a 5MHz SCLK, it should take less
than 500ms to complete.
2013 CML Microsystems Plc
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