AIS Baseband IC with/without RF Synthesiser
CMX7032/CMX7042
7.5.2 Rx Task Operation
Typical stages of Rx task operation are depicted in Figure 12 and occur as follows:
1. A Modem task instructs the CMX7032/CMX7042 to transfer data from the Rx1/2 Modem to the
Rx1/2 Data Buffer.
2. The host writes to the Command register, specifying a Data task. This results in transfer of up to
4 words from the Rx1/2 Data Buffer into the Read Data C-BUS registers, from where it can be
read by the host µC.
3. Steps 2 can be repeated (with host µC reads of the Read Data registers) to transfer a large block
of data from the Rx1/2 Data Buffer to the host µC.
4. Once the system is up and running any modem task may take some time to execute, as it will
need to wait for the data to be available from the modem.
Command Register
Command Reg Free
Data Task
Modem Task
Rx Data
Buffer
(88 words)
sw
sw
demodulator
RxState1/2
demodulator
Rx Data
Buffer
(88 words)
C-Bus
registers
R1BRDY
R1BOVF
R2BOVF
R2BRDY
B
9
B
8
A
A
A
9
select
Rx Data
Buffer
(88 words)
sw
sw
Rx Data
Buffer
Data Task Complete
(88 words)
Figure 12 Rx Task Operation
2012 CML Microsystems Plc
30
D/7032/42_FI1.2/13
CMLMICRO [ CML MICROCIRCUITS ]
