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4-16
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-MSO. NMSl3 pins are all available for other pur-
poses.
1 = SCC3 is not connected to a multiplexed serial interface but is con-
nected directly to the NMSl3 pins or SCP pins or is not used. The
choice of general-purpose 1/0 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-MSO. NMSl2 pins are all available for other pur-
poses.
1 = SCC2 is not connected to a multiplexed serial interface but is either
connected directly to the NMSl2 pins or not used. The choice of
general-purpose 1/0 port pins versus SCC2 functions is made in the
port A control register.
MS1-MSO -
Mode Supported
00 = NMSI Mode
When working in NMSI mode, SCC1 is connected directly to the
seven NMSl1 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-PAO. Four of the SCC3 functions can
be routed to port A or retained as PA11-PA8. The other three SCC3
functions (CTS3, RTS3, and CD3) can be routed to replace the three
SCP pins or else not used.
In NMSI mode, the MSC2 and MSC3 bits are ignored. The choice of
general-purpose 1/0 port pins versus SCC2 and SCC3 functions is
made in the port A control register. See 3.3 PARALLEL 1/0 PORTS
for an example and more information. The choice of SCP pins versus
three SCC3 functions is made in the SPMODE register in the SCP.
See 4.6 SERIAL COMMUNICATIONS PORT (SCP) for more details.
MC68302 USER'S MANUAL
MOTOROLA
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