Table of Contents
Advertisement
Note:
Bit 2 of the TNAF register must be programmed to one; the DS21354/554 does not automatically set this
bit
14.3 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 2 ms to retrieve the data before it is lost. The MSB of each register is the first
received. Please see the register descriptions below for more details.
On the transmit side, there is also a set of eight registers (TSiAF, TSiNAF, TRA, TSa4 to TSa8) that via
the Transmit Sa Bit Control Register (TSaCR), can be programmed to insert both Si and Sa data. 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 2 ms to update the data or
else the old data will be retransmitted. The MSB of each register is the first bit transmitted. Please see the
register descriptions below and Figure 19-15 for more details.
REGISTER
ADDRESS (HEX)
RSiAF
RSiNAF
RRA
RSa4
RSa5
RSa6
RSa7
RSa8
TSiAF
TSiNAF
TRA
TSa4
TSa5
TSa6
TSa7
TSa8
TSaCR: TRANSMIT Sa BIT CONTROL REGISTER (Address=1C Hex)
(MSB)
SiAF
SiNAF
SYMBOL
POSITION NAME AND DESCRIPTION
SiAF
TSaCR.7
FUNCTION
58
The eight Si bits in the align frame
59
The eight Si bits in the non–align frame
5A
The eight reportings of the receive remote alarm (RA)
5B
The eight Sa4 reported in each CRC4 multiframe
5C
The eight Sa5 reported in each CRC4 multiframe
5D
The eight Sa6 reported in each CRC4 multiframe
5E
The eight Sa7 reported in each CRC4 multiframe
5F
The eight Sa8 reported in each CRC4 multiframe
50
The eight Si bits to be inserted into the align frame
51
The eight Si bits to be inserted into the non–align frame
52
The eight settings of remote alarm (RA)
53
The eight Sa4 settings in each CRC4 multiframe
54
The eight Sa5 settings in each CRC4 multiframe
55
The eight Sa6 settings in each CRC4 multiframe
56
The eight Sa7 settings in each CRC4 multiframe
57
The eight Sa8 settings in each CRC4 multiframe
RA
Sa4
International Bit in Align Frame Insertion Control Bit.
0 = do not insert data from the TSiAF register into the transmit data
stream
1 = insert data from the TSiAF register into the transmit data stream
59 of 117
Sa5
Sa6
DS21354 & DS21554
(LSB)
Sa7
Sa8
Advertisement
Table of Contents
