CMX981 Consumer Microcircuits Limited, CMX981 Datasheet - Page 16

• Manufacturer Part Number: CMX981
• Description: Advanceddigital Radio Baseband Processor (tetra Etc.)
• Manufacturer: Consumer Microcircuits Limited

Advanced Digital Radio Baseband Processor
5.5.8
5.6
 2002 CML Microsystems Plc
Output Drivers
The decoded analogue signal is driven off the CMX981 via either a differential speaker driver or a
single-ended earpiece driver. The integrated speaker driver is capable of driving 100mW into an
8 load and the integrated earpiece driver is capable of driving 16.5mW into a 32 load.
Serial Interface
All digital data I/O and control functions for the CMX981 are via the serial interface. The device
has three serial interface ports. Two of these are dedicated fast serial buses (FSBs), the other is
selectable between an FSB and C-BUS interface, under control of the CBUSEN pin.
Cmd1 (CmdFS1/CCLK, CmdDat1/CDATA, CmdRdFS1/CSN, CmdRdDat1/RDATA pins)
Cmd2 (CmdFS2, CmdDat2, CmdRdFS2, CmdRdDat2 pins)
TxRx (TxFS, TxDat, RxFS, RxDat pins)
FSB mode (CBUSEN held low)
Read and write commands can be issued on this port using the CmdFS1 and CmdDat1 pins.
Read data is returned on the CmdRdFS1 and CmdRdDat1 pins. The CmdDat1 pin can be
configured as a bidirectional I/O pin for reading.
C-BUS mode (CBUSEN held high)
Read and write commands can be issued on this port using the CCLK, CDATA and CSN pins.
Read data is returned on the RDATA pin.
Read and write commands can be issued on this port using the CmdFS2 and CmdDat2 pins.
Read data is returned on the CmdRdFS2 and CmdRdDat2 pins.
Only write commands can be issued on this port using the TxFS and TxDat pins. The RxFS
and RxDat pins normally issue receive data, but can be configured to return read data
requested from Cmd1 and Cmd2. It is envisaged that this port will be used for writing Tx data
to the FIFO and reading Rx data.
-10
-20
-30
-40
-50
10
0
0
1000
Figure 4 Voice Codec Filter Response
2000
Frequency (Hz)
16
3000
4000
5000
CMX981
D/981/1