CMX981 Consumer Microcircuits Limited, CMX981 Datasheet - Page 31

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

Advanced Digital Radio Baseband Processor
5.11.16 $12
5.11.17 $13
 2002 CML Microsystems Plc
Setting any of bits 4 to 0 high will power down the appropriate section of the device.
Setting bit 5 high will speed up the digital outputs, reducing rise and fall times, but increasing
power consumption and ground bounce.
Setting bit 7 high will bypass the Rx ADC passive filter.
Setting bit 6 high will bypass the Tx DAC passive filter.
Bit 5 will bypass the voice codec IIR filter allowing direct access to the ADC/DAC. This option will
also increase the codec sample clock to 32kHz and configure the CodecData register as a 16-bit
interface.
Setting bit 4 high will connect the output of the codec DAC to the input of the codec ADC.
Setting bit 3 high will connect the output of the Tx DAC to the input of the Rx ADC, thus passing
transmit constellation data through a raised cosine filter and allowing the resultant data samples to
be monitored digitally at the Rx output.
Bit 2 will enable access to the receive path data access point.
Bit 1 will enable access to the transmit path data access point.
Setting bit 0 high will connect the output of the Tx path data operator to the Rx port. Data is taken
from the I and Q channels on alternate sample clocks.
Bit
Bit
Not used.
Rx ADC
Set this
Bypass
passive
bit low.
filter
7
7
PowerDownCtrl
LoopBackCtrl
Not used.
Tx DAC
Set this
passive
Bypass
bit low.
filter
6
6
Set pins
Bypass
fast
IIR
5
5
Power Down Control Register
Loop Back Control Register
31
bias chain
loop back
analogue
analogue
Enable
Power
codec
down
4
4
down Aux
loop back
analogue
Enable
Power
DAC4
3
3
down Aux
data path
receive
Enable
access
Power
DAC3
2
2
down Aux
data path
transmit
Enable
access
Power
DAC2
1
1
down Aux
loop back
Enable
Power
DAC1
digital
0
0
CMX981
D/981/1