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DS21354 & DS21554
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CCR1: COMMON CONTROL REGISTER 1
(Address=14 Hex)
(MSB)
(LSB)
FLB
THDB3
TG802
TCRC4
RSM
RHDB3
RG802
RCRC4
SYMBOL
POSITION
NAME AND DESCRIPTION
FLB
CCR1.7
Framer Loopback.
0 = loopback disabled
1 = loopback enabled
THDB3
CCR1.6
Transmit HDB3 Enable.
0 = HDB3 disabled
1 = HDB3 enabled
TG802
CCR1.5
Transmit G.802 Enable.
See Section 19 for details.
0 = do not force TCHBLK high during bit 1 of timeslot 26
1 = force TCHBLK high during bit 1 of timeslot 26
TCRC4
CCR1.4
Transmit CRC4 Enable.
0 = CRC4 disabled
1 = CRC4 enabled
RSM
CCR1.3
Receive Signaling Mode Select.
0 = CAS signaling mode
1 = CCS signaling mode
RHDB3
CCR1.2
Receive HDB3 Enable.
0 = HDB3 disabled
1 = HDB3 enabled
RG802
CCR1.1
Receive G.802 Enable.
See Section 19 for details.
0 = do not force RCHBLK high during bit 1 of timeslot 26
1=force RCHBLK high during bit 1 of timeslot 26
RCRC4
CCR1.0
Receive CRC4 Enable.
0 = CRC4 disabled
1 = CRC4 enabled
6.2 Framer Loopback
When CCR1.7 is set to a one, the DS21354/554 will enter a Framer LoopBack (FLB) mode. See Figure
3-1 for more details. This loopback is useful in testing and debugging applications. In FLB, the SCT will
loop data from the transmit side back to the receive side. When FLB is enabled, the following will occur:
1.
Data will be transmitted as normal at TPOSO and TNEGO.
2.
Data input via RPOSI and RNEGI will be ignored.
3.
The RCLK output will be replaced with the TCLK input.