____________________________________________________ DS34T101, DS34T102, DS34T104, DS34T108
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Register Name
Description
Functions
Page
Transmit Latched Status Register 1
Tx SLC-96 multiframe alignment event
Receive Control Register 2
Rx SLC-96 enable control bit
Receive SLC-96 Data Link Registers 1 to 3
Rx SLC-96 overhead values
Receive Latched Status Register 7
Rx SLC-96 multiframe alignment event
10.11.16.1 Transmit SLC–96
The
TFDL register is used to insert the SLC-96 message fields. To insert the SLC-96 message using the
TFDLregister, the system should configure the transmit formatter as follows:
Enable Transmit SLC-96
Source Fs bits via TFDL or SLC-96 formatter
SF (D4) framing Mode
Do not pass through TSER F-bits.
With these settings, the transmit formatter automatically inserts the 12-bit alignment pattern in the Fs bits for the
SLC-96 data link frame. Data from the
TSLC registers is inserted into the remaining Fs bit locations of the SLC-96
multiframe. The status bit
TLS1.TSLC96 is set to indicate that the SLC-96 data link buffer has been transmitted and
that the user should write new message data into the
TSLC registers. The CPU has 9ms after the assertion of
TLS1.TSLC96 to write the
TSLC registers as needed. If no new data is provided in these registers, the previous
values are retransmitted.
10.11.16.2 Receive SLC–96
To enable the receive framer to synchronize onto a SLC–96 pattern, the system should configure the receive
framer as follows:
RCR1-T1.RFM = 1
SF (D4) framing mode
RCR1-T1.SYNCC = 1
Set to cross-couple Ft and Fs bits
Enable SLC-96 synchronizer
RCR1-T1.SYNCT = 0
Set to minimum sync time
The received SLC–96 message bits can be read from the
RSLC registers. The
RLS7-T1.RSLC96 status bit is
useful for retrieving SLC-96 message data. The RSLC96 bit indicates when the framer has updated the
RSLCregisters with the latest message data from the incoming data stream. After the RSLC96 bit is set, the CPU has
9ms (i.e. until the next RSLC96 interrupt) to retrieve the most recent message data from the
RSLC registers. Note
that RSLC96 is not set if the framer is unable to detect the 12-bit SLC-96 alignment pattern.
10.12 HDLC Controllers
This device has an enhanced HDLC controller that can be mapped into a single timeslot, or the T1 FDL or one of
the E1 Sa4 to Sa8 bits. When mapped to a timeslot, the HDLC controller can be configured to use all or only a
subset of the bits of the timeslot.
The HDLC controller performs all the necessary overhead for generating and receiving Performance Report
Messages (PRM) as described in ANSI T1.403 and the messages as described in AT&T TR54016. The HDLC
controller automatically generates and detects flags, generates and checks the CRC checksum, generates and
detects abort sequences, stuffs and de-stuffs zeros, and byte aligns to the data stream. The 64-byte buffers in the
HDLC controller are large enough to allow a full PRM to be received or transmitted without host intervention. The
registers related to the HDLC are displayed in the following table.
Register Name
Description
Functions
Page
Rx HDLC Control Register
Rx HDLC mapping to DS0 or FDL
Rx HDLC Bit Suppress Register
Rx bit suppress within the channel
Rx HDLC FIFO Control
Rx FIFO high water mark