
Serial Interface with Time Slot Assigner
7-86
MC68360 USER’S MANUAL
MOTOROLA
7.8.5.3 SI CLOCK ROUTE REGISTER (SICR).
The 32-bit SICR is used to define the SCC
clock sources. The clock source can be one of the four baud rate generators or an input from
a bank of clock pins. The SICR appears to the user as a memory-mapped, read-write reg-
ister and is cleared at reset.
GRx—Grant Support of SCCx
0 = SCCx transmitter does not support the grant mechanism. The grant is always as-
serted internally.
1 = SCCx transmitter supports the grant mechanism as determined by the GMx bit of
its channel.
SCx—SCCx Connection
0 = SCCx is not connected to the multiplexed SI but is either connected directly to the
NMSIx pins or is not used. The choice of general-purpose I/O port pins versus
SCCn pins is made in the parallel I/O control register.
1 = SCCx is connected to the multiplexed SI. The NMSIx receive pins are available for
other purposes.
RxCS—Receive Clock Source for SCCx
These bits are ignored when the SCCx is connected to the TSA (SCx = 1).
000 = SCCx receive clock is BRG1.
001 = SCCx receive clock is BRG2.
010 = SCCx receive clock is BRG3.
011 = SCCx receive clock is BRG4.
100 = SCCx receive clock for x = 1,2 is CLK1 and for x = 3,4 is CLK5.
101 = SCCx receive clock for x = 1,2 is CLK2 and for x = 3,4 is CLK6.
110 = SCCx receive clock for x = 1,2 is CLK3 and for x = 3,4 is CLK7.
111 = SCCx receive clock for x = 1,2 is CLK4 and for x = 3,4 is CLK8.
TxCS—Transmit Clock Source for SCCx
These bits are ignored when SCCx is connected to the TSA (SCx = 1).
000 = SCCx transmit clock is BRG1.
001 = SCCx transmit clock is BRG2.
010 = SCCx transmit clock is BRG3.
011 = SCCx transmit clock is BRG4.
100 = SCCx transmit clock for x = 1,2 is CLK1 and for x = 3,4 is CLK5.
101 = SCCx transmit clock for x = 1,2 is CLK2 and for x = 3,4 is CLK6.
110 = SCCx transmit clock for x = 1,2 is CLK3 and for x = 3,4 is CLK7.
111 = SCCx transmit clock for x = 1,2 is CLK4 and for x = 3,4 is CLK8.
31
GR4
15
GR2
30
SC4
14
SC2
29
28
27
26
25
24
23
GR3
7
GR1
22
SC3
6
SC1
21
20
19
18
17
16
R4CS
12
R2CS
T4CS
9
T2CS
R3CS
4
R1CS
T3CS
1
T1CS
13
11
10
8
5
3
2
0