![](http://datasheet.mmic.net.cn/100000/FX980L6_datasheet_3487758/FX980L6_24.png)
TETRA Baseband Processor
FX980
1997 Consumer Microcircuits Limited
24
D/980/3
TxData
Title:
Transmit Data register
Address:
$0x04 - $0x07 (Mapped over four locations, two address bits being used as data bits)
Function:
W
FIFO input
R
FIFO output
Description:
This transmit data register is 10 bits wide. The two least significant bits of the address bus are
used to drive bits 8 and 9, hence it can be considered to be mapped over four consecutive
locations. This data word is written into a FIFO. The function is only decoded when the FIFO is
read (there is an exception for the first data word). The FIFO will be read when the Tx Data path
demands data. This will only occur when the TxEn bit of the TxSetup register is set active. For
test purposes the FIFO data output may be accessed by reading these registers.
Data write with symbol modulator not bypassed
Bit
Name
Active State
Function
9
TxRampUp
High
W
This bit is written to the FIFO. While the TxEn bit of the
TxSetup register is active, it controls the Tx Data path
ramping. Setting it active will cause the amplitude to ramp
up to its full value, conversely setting the bit inactive will
cause the amplitude to ramp down to its minimum value. If
the bit is changed while the amplitude is being ramped, the
ramp direction will change to the direction set by this bit.
While the TxRampEn bit is inactive, the TxRampUp bit will
directly control the transmit amplitude (High meaning full
amplitude and Low meaning zero amplitude).
8
MultiSymbol
High
W
This bit is written to the FIFO and when this bit is set
active, the FIFO symbol data will be marked as a four
symbol word. When set inactive, the FIFO symbol data
will be marked as a single symbol word. This bit is inactive
if the SymbModuBypass bit of the ConfigCtrl1 register is
active.
7:6
TxRelSymbol4
Data
W
Fourth symbol in word to be written to FIFO.
5:4
TxRelSymbol3
Data
W
Third symbol in word to be written to FIFO.
3:2
TxRelSymbol2
Data
W
Second symbol in word to be written to FIFO.
1:0
TxRelSymbol1
Data
W
First symbol in word to be written to FIFO.
Data write with symbol modulator bypassed
Bit
Name
Active State
Function
9
TxRampUp
High
W
(See above)
8:3
(not used)
Data
W
Redundant data which is still written into the FIFO. Set
these bits Low.
2:0
TxAbsSymbol
Data
W
IQ constellation point which is written into the FIFO.