
CTM
REFERENCE
MOTOROLA
6-5
MODULUS COUNTER SUBMODULE (MCSM)
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6
6.8.1
MCSMSIC — MCSM status/interrupt/control register
COF — Counter overflow flag bit
This status flag bit indicates whether or not a counter overflow has occurred. An overflow of the
MCSM counter is defined to be the transition of the counter from $FFFF to $xxxx, where $xxxx is
the value contained in the modulus latch. If the IL field is non-zero, an interrupt request is
generated when the COF bit is set.
1 (set)
–
Counter overflow has occurred.
0 (clear) –
Counter overflow has not occurred.
This flag bit is set only by the hardware and cleared only by the software or by a system reset. To
clear the flag, the software must first read the bit (as ‘one’) then write a ‘zero’ to the bit.
Note:
The flag clearing mechanism will work only if no flag setting event occurs between the
read and write operations; if a COF setting event occurs between the read and write
operations, the COF bit will not be cleared.
(1) Offset fromthe base address of the MCSMsubmodule.
(1) Offset fromthe base address of the MCSMsubmodule.
Table 6-1
MCSM register map
Address
(1)
$00
$02
$04
$06
15
8 7
0
MCSMstatus/interrupt/control register (MCSMSIC)
MCSMcounter (MCSMCNT)
MCSMmodulus latch (MCSMML)
Bit:
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
MCSMSIC
$00
(1)
COF
IL2
IL1
IL0
IARB3
DRVA DRVB
IN2
IN1
EDGEN EDGEP
CLK2 CLK1 CLK0
Reset:
0
0
0
0
0
0
0
0
u
u
0
0
0
0
0
0
F
.
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