
MC68CK338
MC68CK338TS/D
MOTOROLA
93
NOTE
The clock input of MCSM2 is internally connected to I/O pin CTD27 for DASM27
and will read the state of that pin. The clock inputs of MCSM30 and MCSM31 are
internally connected to I/O pin CTD5 for DASM5 and will read the state of that pin.
The MCSM counter register is a read/write register. A read returns the current value of the counter. A
write simultaneously loads both the counter and the MCSM modulus latch with the specified value. The
counter then begins incrementing from this new value.
The MCSM modulus latch register is a read/write register. A read returns the current value of the latch.
A write pre-loads the latch with a new value that the modulus counter will begin counting from when the
next load condition occurs.
6.9 Single Action Submodule (SASM)
The single action submodule (SASM) provides two identical channels, each having its own input/output
pin, but sharing the same interrupt logic, priority level, and arbitration number. Each channel can be
configured independently to perform either input capture or output compare.
Table 55
shows the differ-
ent operational modes.
NOTES:
1. When a channel is operating in IC mode, the IN bit in the SIC register reflects the logic
state of the corresponding input pin (after being Schmitt triggered and synchronized).
2. When a channel is operating in OC, OCT, or OP mode, the IN bit in the SIC register
reflects the logic state of the output of the output flip-flop.
MCSM2CNT —
MCSM2 Counter Register
MCSM30CNT —
MCSM30 Counter Register
MCSM31CNT —
MCSM31 Counter Register
$YFF412
$YFF4F2
$YFF4FA
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
MCSM2ML —
MCSM2 Modulus Latch
MCSM30ML —
MCSM30 Modulus Latch
MCSM31ML —
MCSM31 Modulus Latch
$YFF414
$YFF4F4
$YFF4FC
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 55 SASM Operational Modes
Mode
Function
IC
1
Input capture either on a rising or falling edge or as a read-only input port
OC
2
Output compare
OCT
2
Output compare and toggle
OP
2
Output port