AIS Baseband IC with/without RF Synthesiser
CMX7032/CMX7042
7.5.1 Tx Task Operation
Typical stages of Tx task operation are depicted in Figure 11 and occur as follows:
1. The host writes up to 4 words of data for transmission into the Write Data C-BUS registers.
2. The host writes the Command register, specifying a data task. This results in transfer of the data
from the Write Data registers into the Tx Data Buffer.
3. Steps 1 and 2 can be repeated to load the Tx Data Buffer with a large block of data.
4. A Modem task can then be used to instruct the Tx Modulator to transmit the data in the Data
Buffer. This causes the content of the Tx Data Buffer to be coded and CRC’d (if in burst mode)
and transmitted to the MOD1 and MOD2 output pins.
5. Once the system is up and running any modem task may potentially take some time to execute as
it may have to wait for the previous task to complete.
Command Register
Command Reg Free
Data Task
Modem Task
C-Bus
registers
B
7
B
6
A
8
A
7
Tx Data Buffer
(88 words)
Modulator
Data Task Complete
TBFree
TxDone
TxState
Figure 11 Tx Task Operation
2012 CML Microsystems Plc
29
D/7032/42_FI1.2/13
CMLMICRO [ CML MICROCIRCUITS ]
