Maxim DS21Q55 specifications E1 FRAMER/FORMATTER Control Registers, E1 Control Registers, E1RCR1

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9. E1 FRAMER/FORMATTER CONTROL REGISTERS

The E1 framer portion of the DS21Q55 is configured via a set of four control registers. Typically, the control registers are only accessed when the system is first powered up. Once the device has been initialized, the control registers will only need to be accessed when there is a change in the system configuration. There are two receive control registers (E1RCR1 and E1RCR2) and two transmit control registers (E1TCR1 and E1TCR2). There are also four status and information registers. Each of these eight registers are described in this section.

9.1 E1 Control Registers

Register Name:	E1RCR1
Register Description:	E1 Receive Control Register 1
Register Address:	33h

Bit #

Name

Default

7	6	5	4	3	2	1	0
RSERC	RSIGM	RHDB3	RG802	RCRC4	FRC	SYNCE	RESYNC
0	0	0	0	0	0	0	0

Bit 0/Resync (RESYNC). When toggled from low to high, a resync is initiated. Must be cleared and set again for a subsequent resync.

Bit 1/Sync Enable (SYNCE).

0 = auto resync enabled

1 = auto resync disabled

Bit 2/Frame Resync Criteria (FRC). 0 = resync if FAS received in error 3 consecutive times

1 = resync if FAS or bit 2 of non-FAS is received in error three consecutive times

Bit 3/Receive CRC4 Enable (RCRC4). 0 = CRC4 disabled

1 = CRC4 enabled

Bit 4/Receive G.802 Enable (RG802). See Signaling Operation for details.

0 = do not force RCHBLK high during bit 1 of timeslot 26 1 = force RCHBLK high during bit 1 of timeslot 26

Bit 5/Receive HDB3 Enable (RHDB3). 0 = HDB3 disabled

1 = HDB3 enabled

Bit 6/Receive Signaling Mode Select (RSIGM). 0 = CAS signaling mode

1 = CCS signaling mode

Bit 7/RSER Control (RSERC).

0 = allow RSER to output data as received under all conditions

1 = force RSER to one under loss of frame alignment conditions

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