Rainbow Electronics DS26504 - Manual (Page 45)

DS26504 T1/E1/J1/64KCC BITS Element
45 of 128
9. E1 FRAMER/FORMATTER CONTROL REGISTERS
The E1 framer portion of the DS26504 is configured via a set of two control registers. Typically, the
control registers are only accessed when the system is first powered up. Once the DS26504 has been
initialized, the control registers only need to be accessed when there is a change in the system
configuration. There is one receive control register (E1RCR) and one transmit control register (E1TCR).
There are also two information registers and a status register, as well as an interrupt mask register. Each
of these registers is described in this section.
9.1 E1 Control Registers
Register Name:
E1RCR
Register Description: E1 Receive Control Register
Register Address: 1Dh
Bit
# 7 6 5 4 3 2 1 0
Name — RLOSA RHDB3 — — FRC SYNCE RESYNC
Default 0 0 0 0 0 0 0 0
HW
Mode
0 0
HBE
PIN 55
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 Criterion (FRC)
0 = resync if FAS received in error three consecutive times
1 = resync if FAS or bit 2 of non-FAS is received in error three consecutive times
Bits 3, 4, 7: Unused, must be set = 0 for proper operation.
Bit 5: Receive HDB3 Enable (RHDB3)
0 = HDB3 disabled
1 = HDB3 enabled
Bit 6: Receive Loss-of-Signal Alternate Criterion (RLOSA). Defines the criterion for a Receive Loss-of-Signal condition.
0 = RLOS declared upon 255 consecutive zeros (125µs)
1 = RLOS declared upon 2048 consecutive zeros (1ms)