Wireless Modem Data Pump
FX909A
Figure 7 The Transmit Process
Figure 8 The Receive Process
Mobitex modem tasks:
B2 B1 B0
Receive Mode
Transmit Mode
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
NULL
SFH
R3H
RDB
SFS
NULL
T7H
Search for Frame Head
Read 3 byte Frame Head
Read Data Block
Search for Frame Sync
Read Single Byte
Transmit 7 byte Frame Head
Reserved
Transmit Data Block
Transmit 4 Bytes
Transmit Single Byte
Transmit Scrambler Output
TDB
TQB
TSB
TSO
RSB
LFSB
Load Frame Sync Bytes
RESET Cancel any current action
RESET Cancel any current action
ã 1996 Consumer Microcircuits Limited
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D/909A/4