ds21ft40 Maxim Integrated Products, Inc., ds21ft40 Datasheet - Page 52

• Manufacturer Part Number: ds21ft40
• Description: Ds21ft40 Four X Three 12 Channel E1 Framer
• Manufacturer: Maxim Integrated Products, Inc.

On the transmit side, data is sampled from the TAF and TNAF registers with the setting of the Transmit
Align Frame bit in Status Register 2 (SR2.3). The host can use the SR2.3 bit to know when to update the
TAF and TNAF registers. It has 250 us to update the data or else the old data will be retransmitted. Data
in the Si bit position will be overwritten if the framer is programmed: (1) to source the Si bits from the
TSER pin, (2) in the CRC4 mode, or (3) have automatic E–bit insertion enabled. Data in the Sa bit
position will be overwritten if any of the TCR2.3 to TCR2.7 bits are set to one. Please see the register
descriptions for TCR1 and TCR2 and the Transmit Data Flow diagram in Section 16 for more details.
RAF: RECEIVE ALIGN FRAME REGISTER (Address=2F Hex)
RNAF: RECEIVE NON–ALIGN FRAME REGISTER (Address=1F Hex)
(MSB)
(MSB)
SYMBOLS
SYMBOLS
Si
Si
Sa4
Sa5
Sa6
Sa7
Sa8
Si
Si
A
0
0
1
1
0
1
1
1
0
1
POSITION
POSITION
RNAF.7
RNAF.6
RNAF.5
RNAF.4
RNAF.3
RNAF.2
RNAF.1
RNAF.0
RAF.7
RAF.6
RAF.5
RAF.4
RAF.3
RAF.2
RAF.1
RAF.0
A
0
NAME AND DESCRIPTION
NAME AND DESCRIPTION
International Bit.
Frame Alignment Signal Bit.
Frame Alignment Signal Bit.
Frame Alignment Signal Bit.
Frame Alignment Signal Bit.
Frame Alignment Signal Bit.
Frame Alignment Signal Bit
Frame Alignment Signal Bit.
International Bit.
Frame Non–Alignment Signal Bit.
Remote Alarm.
Additional Bit 4.
Additional Bit 5.
Additional Bit 6.
Additional Bit 7.
Additional Bit 8.
Sa4
1
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Sa5
1
Sa6
0
Sa7
1
(LSB)
(LSB)
DS21FT40
Sa8
1