Digital PMR Radio Processor
CMX7131/CMX7141
Table 12 Modem Mode Selection
Modem Mode
Modem Control
($C1: b3-0)
0000
0001
0010
0011
0100
0101
1001
TXENA
RXENA
Idle – low power mode
Rx mode
Tx mode
1
1
0
x
1
1
1
x
1
0
1
x
1
0
0
x
reserved
CMX994 Pass-through
Rx with CMX994 I/Q cal (I/Q mode only)
Rx with Powersave (I/Q mode only)
reserved
others
The CMX994 Pass-through mode is used to control and monitor the CMX994 directly. This cannot be
accessed if the CMX7131/CMX7141 is in Rx or Tx modes.
Table 13 Modem Control Selection
4-FSK Modem Control
Rx
Tx
($C1: b7-4)
0000
Rx Idle
Tx Idle
0001
0010
0011
0100
0101
0110
0111
1xxx
Rx NXDN Formatted
Rx NXDN Raw
Rx 4-FSK EYE
Rx Pass-through Mode
reserved
Sync
Reset/Abort
reserved
Tx NXDN Formatted
reserved
Tx 4-FSK PRBS
Tx 4-FSK Preamble
Tx 4-FSK Mod set-up
Tx Repeated Word
Reset/Abort
reserved
The Modem Mode bits and the Modem Control bits should be set together in the same C-BUS write.
6.5.5 Tx Mode NXDN Formatted
In Tx mode, the CMX7131/CMX7141 operates in NXDN formatted mode. The first block of control channel
or payload data should be loaded into the C-BUS TxData registers before executing the mode change. A
“DataReady” IRQ will be asserted when the registers have been read by the CMX7131/CMX7141 and the
host can then supply further blocks of payload data. When all payload has been transmitted the
CMX7131/CMX7141 will issue a “TxDone” IRQ and the host can then reset the Mode bits to either Rx or
IDLE as required.
2014 CML Microsystems Plc
Page 39
D/7141_FI-3.x/6
CMLMICRO [ CML MICROCIRCUITS ]
