SW_SYNC
('C' option is used)
This bit is used to drive the active-low SYNC input of the channel A
receiver. The SYNC signal is asserted when this bit is set (logic 1), and is
deasserted when this bit is clear (logic 0). This is useful in situations
where it is necessary to receive unformatted serial data, as it allows the
SCC receiver to be manually placed into sync under program control.
This bit is ignored if bit 6 is set (logic 1).
Bit 3:
RCKEN --- Receive Clock Source:
When set (logic 1), this bit allows the receive clock (RCLK) signal to be
generated by the TRxC pin on channel B of the SCC. When cleared (logic
0), RCLK is received on pin 17 of the DB-25 connector. In either case,
RCLK is always transmitted on pin 11 of the DB-25 connector.
Bit 2:
TCKEN --- Transmit Clock Source:
When set (logic 1), this bit allows the transmit clock (TCLK) to be
generated by the TRxC pin on channel A of the SCC. When cleared (logic
0), the DTE receives TCLK on pin 15 of the DB-25 connector. In either
case, TCLK is always transmitted on pin 24 of the DB-25 connector.
Bits 1-0:
Reserved, always 0.
IMPORTANT
Local Loopback and Remote Loopback cannot be
enabled simultaneously. Bits 5 and 4 of the
Communications Register should therefore not be set
(logic 1) simultaneously.
Quatech MPAC-100 User's Manual
37