
Communications Processor (CP)
MOTOROLA
MC68302 USER’S MANUAL
4-21
SDC2—Serial Data Strobe Control 2
0 = SDS2 signal is asserted during the B2 channel
1 = SDS1 signal is asserted during the B2 channel
SDC1—Serial Data Strobe Control 1
0 = SDS1 signal is asserted during the B1 channel
1 = SDS2 signal is asserted during the B1 channel
B2RB, B2RA—B2 Channel Route in IDL/GCI Mode or CH-3 Route in PCM Mode
00 = Channel not supported
01 = Route channel to SCC1
10 = Route channel to SCC2 (if MSC2 is cleared)
11 = Route channel to SCC3 (if MSC3 is cleared)
B1RB, B1RA—B1 Channel Route in IDL/GCI Mode or CH-2 Route in PCM Mode
00 = Channel not supported
01 = Route channel to SCC1
10 = Route channel to SCC2 (if MSC2 is cleared)
11 = Route channel to SCC3 (if MSC3 is cleared)
DRB, DRA—D-Channel Route in IDL/GCI Mode or CH-1 Route in PCM Mode
00 = Channel not supported
01 = Route channel to SCC1
10 = Route channel to SCC2 (if MSC2 is cleared)
11 = Route channel to SCC3 (if MSC3 is cleared)
MSC3—SCC3 Connection
0 = SCC3 is connected to the multiplexed serial interface (PCM, IDL, or GCI) chosen
in MS1–MS0. NMSI3 pins are all available for other purposes.
1 = SCC3 is not connected to a multiplexed serial interface but is connected directly to
the NMSI3 pins or SCP pins or is not used. The choice of general-purpose I/O port
pins versus SCC3 functions is made in the port A control register. The choice of
SCP pins versus SCC3 functions is made in the SPMODE register.
MSC2—SCC2 Connection
0 = SCC2 is connected to the multiplexed serial interface (PCM, IDL, or GCI) chosen
in MS1–MS0. NMSI2 pins are all available for other purposes.
1 = SCC2 is not connected to a multiplexed serial interface but is either connected di-
rectly to the NMSI2 pins or not used. The choice of general-purpose I/O port pins
versus SCC2 functions is made in the port A control register.
MS1—MS0—Mode Supported
00 = NMSI Mode
When working in NMSI mode, SCC1 is connected directly to the seven NMSI1
pins (RXD1, TXD1, RCLK1, TCLK1, CD1, CTS1, and RTS1). SCC2 functions can
be routed to port A as NMSI functions or configured instead as PA6–PA0. Four of
the SCC3 functions can be routed to port A or retained as PA11–PA8. The other