DS2154
12.3 Internal Register Scheme Based on CRC4 Multiframe
On the receive side, there is a set of eight registers (RSiAF, RSiNAF, RRA, RSa4 to RSa8) that report the
Si and Sa bits as they are received. These registers are updated with the setting of the Receive CRC4
Multiframe bit in Status Register 2 (SR2.1). The host can use the SR2.1 bit to know when to read these
registers. The user has 2ms to retrieve the data before it is lost. The MSB of each register is the first
received. See the register descriptions below and the Transmit Data Flow diagram (Figure 14-11) for
more details.
On the transmit side, there is also a set of eight registers (TSiAF, TSiNAF, TRA, TSa4 to TSa8) that can
be programmed to insert both Si and Sa data via the Transmit Sa Bit Control Register (TSaCR). Data is
sampled from these registers with the setting of the Transmit Multiframe bit in Status Register 2 (SR2.5).
The host can use the SR2.5 bit to know when to update these registers. It has 2ms to update the data or
else the old data will be retransmitted. The MSB of each register is the first bit transmitted. See the
register descriptions below and the Transmit Data Flow diagram (Figure 14-11) for more details.
REGISTER
NAME
RSiAF
RSiNAF
RRA
ADDRESS
(HEX)
FUNCTION
The 8 Si bits in the align frame
The 8 Si bits in the non-align frame
58
59
5A
5B
5C
5D
5E
5F
50
51
52
53
54
55
56
57
The 8 reportings of the receive remote alarm (RA)
The 8 Sa4 reported in each CRC4 multiframe
The 8 Sa5 reported in each CRC4 multiframe
The 8 Sa6 reported in each CRC4 multiframe
The 8 Sa7 reported in each CRC4 multiframe
The eight Sa8 reported in each CRC4 multiframe
The 8 Si bits to be inserted into the align frame
The 8 Si bits to be inserted into the non-align frame
The 8 settings of remote alarm (RA)
The 8 Sa4 settings in each CRC4 multiframe
The 8 Sa5 settings in each CRC4 multiframe
The 8 Sa6 settings in each CRC4 multiframe
The 8 Sa7 settings in each CRC4 multiframe
The 8 Sa8 settings in each CRC4 multiframe
RSa4
RSa5
RSa6
RSa7
RSa8
TSiAF
TSiNAF
TRA
TSa4
TSa5
TSa6
TSa7
TSa8
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ROCHESTER [ Rochester Electronics ]
