Datasheet

DS21354/DS21554 3.3V/5V E1 Single-Chip Transceivers
68 of 124
TNAF: TRANSMIT NON-ALIGN FRAME REGISTER (Address = 21 Hex)
(MSB) (LSB)
Si 1 A Sa4 Sa5 Sa6 Sa7 Sa8
SYMBOL POSITION NAME AND DESCRIPTION
Si TNAF.7
International Bit.
1 TNAF.6
Frame Non-Alignment Signal Bit.
A TNAF.5
Remote Alarm (used to transmit the alarm).
Sa4 TNAF.4
Additional Bit 4.
Sa5 TNAF.3
Additional Bit 5.
Sa6 TNAF.2
Additional Bit 6.
Sa7 TNAF.1
Additional Bit 7.
Sa8 TNAF.0
Additional Bit 8.
Note: Bit 6 of the TNAF register must be programmed to one. The DS21354/DS21554 do not
automatically set this bit.
13.3.
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. 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 2ms 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 18-15 for more details.
REGISTER ADDRESS (HEX) FUNCTION
RSiAF 58 The eight Si bits in the align frame
RSiNAF 59 The eight Si bits in the non-align frame
RRA 5A The eight reportings of the receive remote alarm (RA)
RSa4 5B The eight Sa4 reported in each CRC4 multiframe
RSa5 5C The eight Sa5 reported in each CRC4 multiframe
RSa6 5D The eight Sa6 reported in each CRC4 multiframe
RSa7 5E The eight Sa7 reported in each CRC4 multiframe
RSa8 5F The eight Sa8 reported in each CRC4 multiframe
TSiAF 50 The eight Si bits to be inserted into the align frame
TSiNAF 51 The eight Si bits to be inserted into the non-align frame
TRA 52 The eight settings of remote alarm (RA)
TSa4 53 The eight Sa4 settings in each CRC4 multiframe
TSa5 54 The eight Sa5 settings in each CRC4 multiframe
TSa6 55 The eight Sa6 settings in each CRC4 multiframe
TSa7 56 The eight Sa7 settings in each CRC4 multiframe
TSa8 57 The eight Sa8 settings in each CRC4 multiframe