Digital PMR Radio Processor
CMX7131/CMX7141
6.3.1 FI Loading from Host Controller
The FI can be included into the host controller software build and downloaded into the
CMX7131/CMX7141 at power-up over the C-BUS interface. The BOOTEN pins must be set to the C-BUS
load configuration, the CMX7131/CMX7141 powered up and placed into Program Mode, the data can then
be sent directly over the C-BUS to the CMX7131/CMX7141.
If the host detects a brownout, the BOOTEN state should be set to re-load the FI. A General Reset should
then be issued and the appropriate FI load procedure followed.
Each time the Programming register, $C8, is written, it is necessary to wait for the PRG flag (Status
register ($C6) b0) to go high before another write to $C8. The PRG flag going high confirms the write to
the Programming register has been accepted. The PRG flag state can be determined by polling the Status
register or by unmasking the interrupt (Interrupt Mask register, $CE, b0).
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 (host dependent).
2014 CML Microsystems Plc
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