
GT-96100A Advanced Communication Controller
376
Revision 1.0
There are two mode of transmit synchronization in transparent mode. They are selected by setting TSYN[12} in
Table 352: Transparent Mode Synchronization Options
Synchronizatio n Option
Description
External Synchronization
(RSYL = ‘00’)
The receiver starts to receive data whenever CD* is asserted and
stops receiving data when CD* is deasserted (if CDM=0) or when the
CPU issues an Enter Hunt Command.
Sync Hunt
RSYL = ‘01’, ‘10’, or ‘11’ (nibble, byte or two bytes sync)
The receiver hunts for the sync pattern, as defined by RSYL.
When the synch pattern is recognized, the receiver starts to receive
data. The receive process stops when CD* is deasserted and CDM=0
or when the CPU issues an enter hunt command.
If bit 15 is set, there is no transfer of the SYNC characters to the
receiver. The syncs are stripped until the first data character is
received, and are not calculated in the packet CRC. If bit 15 is reset,
sync characters that appear after the sync pattern is recognized are
regarded as data.
On the transmitter side, in sync hunt mode, two sync characters are
always sent at the beginning of a frame.
NOTE: When RSYL equals 01, the Sync pattern is defined by bits
[7:4] of the Sync Register.
Table 353: Transmitter Mode Synchronization Options
Synchronizatio n Option
Description
TSYN = 0
Synchronization is achieved whenever CTS* is asserted.
TSYN=1
Synchronization is achieved after receiver synchronization and CTS*
is asserted. The transmitter always starts to transmit on the receive
byte boundaries. In external synchronization, when CTS* is asserted,
the transmitter starts to transmit 8 bits after CD* assertion. In sync
hunt mode, when CTS* is asserted, the transmitter starts to transmit 8
bits after sync recognition. If CTS* is deasserted after the receiver
gains synchronization, the transmitter waits to the byte boundary
before it starts to transmit.