CMX981 Consumer Microcircuits Limited, CMX981 Datasheet - Page 41

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

Advanced Digital Radio Baseband Processor
5.11.36 $3C-$3F
5.11.37 $40-$4B
 2002 CML Microsystems Plc
$3C-$3D
$3E-$3F
These registers allow direct access to the transmit data path values just after the gain, phase and
offset adjustment. Both read and write operations are permitted. A read operation reads the signal
values on the I and Q channels. A write operation will write data directly to the sigma-delta DAC
input. To prevent normal data overwriting these values, bit 1 in the LoopBackCtrl register should
be set. The MSB read data is buffered to enable access to a discrete sample value (if the register
was not buffered, data from different sample periods could be in the MSB and LSB registers).
Therefore the LSB register must be read first for correct operation.
$40-$41
$42-$43
$44-$45
$46-$47
$48-$49
$4A-$4B
These registers enable the user to inspect the conversion value for each of the six auxiliary ADCs.
There are two read registers per ADC, one to obtain the two least significant bits of the data, the
other for the eight most significant bits. Reading these registers does not affect the ADC
conversion cycle. Reading the MSB register directly reads the ADC output and simultaneously
causes the two bits in the LSB register to be written to a holding register. This holding register is
read when the LSB register is read. This mechanism is necessary to allow the user to read MSB
and LSB data from the same ADC conversion cycle. If only the MSB register is read, the converter
can be considered as an 8-bit ADC. If a 10-bit conversion is required, the MSB register must be
read first.
$41, $43, $45, $47, $49, $4B
$3C, $3E
$40, $42, $44, $46, $48, $4A
$3D, $3F
Bit
Bit
Bit
Bit
Not used.
undefined
Bit value
Set this bit
Not Used.
7
7
low.
TxDPData
TxDPIData
TxDPQData
AuxAdcData
AuxAdcData1
AuxAdcData2
AuxAdcData3
AuxAdcData4
AuxAdcData5
AuxAdcData6
7
7
undefined
Not used.
Bit value
Not Used.
Set this
bit low.
6
6
6
6
undefined
Not used.
Bit value
5
5
5
5
Transmit Data Access Points
Transmit I Channel Data Access Point
Transmit Q Channel Data Access Point
Auxiliary ADC Data Registers (Read only)
Auxiliary ADC 1 Data Register
Auxiliary ADC 2 Data Register
Auxiliary ADC 3 Data Register
Auxiliary ADC 4 Data Register
Auxiliary ADC 5 Data Register
Auxiliary ADC 6 Data Register
Transmit channel data [7:0]
41
ADC Data [9:2]
undefined
Not used.
Bit value
4
4
4
4
Transmit channel data [13:8]
3
3
undefined
Not used.
Bit value
3
3
2
2
undefined
Not used.
Bit value
2
2
1
1
ADC Data [1:0]
1
1
CMX981
D/981/1
0
0
0
0