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DS3171/DS3172/DS3173/DS3174
187
12.9.3 Transmit G.751 E3
The transmit G.751 E3 utilizes two registers.
12.9.3.1 Register Map
Table 12-25. Transmit G.751 E3 Framer Register Map
Address
Register
Register Description
(1,3,5,7)18h E3G751.TCR
E3 G.751 Transmit Control Register
(1,3,5,7)1Ah E3G751.TEIR
E3 G.751 Transmit Error Insertion Register
(1,3,5,7)1Ch
-- Reserved
(1,3,5,7)1Eh
-- Reserved
12.9.3.2 Register Bit Descriptions
Register Name:
E3G751.TCR
Register Description:
E3 G.751 Transmit Control Register
Register Address:
(1,3,5,7)18h
Bit
# 15 14 13 12 11 10 9 8
Name
Reserved --
-- Reserved
Reserved
Reserved
TNBC1
TNBC0
Default
0 0 0 0 0 0 0 0
Bit
# 7 6 5 4 3 2 1 0
Name -- --
Reserved
Reserved
TABC1
TABC0
TFGC
TAIS
Default
0 0 0 0 0 0 0 0
Bits 9 to 8: Transmit N Bit Control (TNBC[1:0])
– These two bits control the source of the N bit.
00 = 1
01 = transmit data from HDLC controller.
10 = transmit data from FEAC controller.
11 = 0
Note: If TNBC[1:0] is 10 and TABC[1:0] is 01, both the N bit and A bit will carry the same transmit FEAC controller
(one bit per frame period), however, the N bit and A bit in the same frame may or may not be equal.
Bits 3 to 2: Transmit A Bit Control (TABC[1:0])
– These two bits control the source of the A bit.
00 = automatically generated based upon received E3 alarms.
01 = transmit from the FEAC controller.
10 = 0
11 = 1
Note: If TABC[1:0] is 01 and TNBC[1:0] is 10, both the A bit and N bit will carry the same transmit FEAC controller
(one bit per frame period), however, the A bit and N bit in the same frame may or may not be equal.
Bit 1: Transmit Frame Generation Control (TFGC)
– When this bit is zero, the Transmit Frame Processor frame
generation is enabled. The E3 overhead positions in the incoming E3 payload will be overwritten with the internally
generated E3 overhead. When this bit is one, the Transmit Frame Processor frame generation is disabled. The E3
overhead positions in the incoming E3 payload will be passed through to error insertion. Note: The E3 overhead
periods can still be overwritten by overhead insertion.
Bit 0: Transmit Alarm Indication Signal (TAIS)
– When 0, the normal signal is transmitted. When 1, the output
E3 data stream is forced to all ones (AIS).