XR72L52 Datasheet, PDF (88/480 Pages) Exar Corporation – TWO CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

XRT72L52
REV. 1.0.1
xr
TWO CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
2.3.3.11 Receive E3 TTB-0 Register (E3, ITU-T G.832)
RXE3 TTB-0 REGISTER (ADDRESS = 0X1C)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
RxTTB-0
RO
RO
RO
RO
RO
RO
RO
RO
0
0
0
0
0
0
0
0
This Read-Only register contains the frame start marker byte of the 16 byte Trail Trace Buffer Message that
has been received from the Remote Terminal, via the TR byte-field within the incoming E3 frames. The re-
maining bytes, of this Trail Trace Buffer Message can be found in the RxTTB-1 through RxTTB-15 registers.
The data in this register is typically of the form [1, C6, C5, C4, C3, C2, C1, C0]. The "1" in the MSB position
identifies this byte as being the frame start marker (e.g., the first byte within the 16 byte Trail Trace Buffer Mes-
sage). The remaining bits: C0 - C6 contain the CRC-7 value that was calculated over the previous 16 byte Trail
Trace Buffer Message.
NOTES:
1. The XRT72L52 Framer device will not compute or verify this CRC-7 value. It is up to the user's hardware and/or
software to compute and verify this value.
2. For more information on the use of this register, refer to Section 6.3.2.9.
2.3.3.12 Receive E3 TTB-1 Register (E3, ITU-T G.832)
RXE3 TTB-1 REGISTER (ADDRESS = 0X1D)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
RxTTB-1
RO
RO
RO
RO
RO
RO
RO
RO
0
0
0
0
0
0
0
0
This Read-Only register contains the second (2nd) byte within the 16 byte Trail Trace Buffer Message, that has
been received from the Remote Terminal. This register typical contains an ASCII character that is required for
the E.164 numbering format.
NOTE: For more information on the use of this register, refer to Section 6.3.2.9.
2.3.3.13 Receive E3 TTB-2 Register (E3, ITU-T G.832)
RXE3 TTB-2 REGISTER (ADDRESS = 0X1E)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
RxTTB-2
RO
RO
RO
RO
RO
RO
RO
RO
0
0
0
0
0
0
0
0
This Read-Only register contains the third (3rd) byte within the 16 byte Trail Trace Buffer Message, that has
been received from the Remote Terminal. This register typical contains an ASCII character that is required for
the E.164 numbering format.
NOTE: For more information on the use of this register, refer to Section 6.3.2.9.
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