Digital PMR Radio Processor
CMX7131/CMX7141
note:
RAMDAC has been enabled
Data is in 9 byte blocks
Tx_Process
Load data to C-BUS
TxDataBlock
transaction count =0,
byte count =9
Set Modem Control to:
4FSK, Mode = Tx
GPIO2 and GPIO1 will change to 01 and the Modem will transmit
the preamble, frame sync and data The host should ensure that
any external hardware is also set into Tx mode (if not automatically
controlled by the GPIO pins).
note:
Ensure that RAMDAC speed
is fast enough to allow for
hardware and internal
processing delays
note:
Execute RAMDAC up
No
IRQ = DataRdy?
yes
more data to send?
yes
No
IRQ=Error, Modem status
= Underflow may occur at
this point, if enabled.
note:
Load data to C-BUS
TxDataBlock
transaction count ++,
byte count =9
No
Due to internal processing delays in the filters etc, the
Host should wait for IRQ=TxDone or implement its
own delay to ensure all data has been transmitted.
note:
IRQ = TxDone?
Yes
Execute RAMDAC down
Set Modem Control to Idle:
Mode = Idle
Goto Rx_Process
See Rx_Process flow
diagram
GPIO2 and GPIO1 will change to 11 and
the Modem will drop into Idle mode. The
host should ensure that any external
note:
note:
hardware is also set into Idle mode (if not
automatically controlled by the GPIO pins).
Goto Idle Mode
Figure 19 Tx Data Flow
2014 CML Microsystems Plc
Page 43
D/7141_FI-3.x/6
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