Table D-5 Port F Pin Assignments
PFPAR Field
PFPA7
PFPA6
PFPA5
PFPA4
PFPA3
PFPA2
PFPA1
PFPA0
Port F Signal
PF7
Control Signal
IRQ7
PF6
IRQ6
PF5
IRQ5
PF4
IRQ4
PF3
IRQ3
PF2
IRQ2
PF1
IRQ1
PF0
MODCLK
D.3.12 SYPCR — System Protection Control Register
$YFFA21
15
8
7
6
5
0
4
0
3
2
1
0
NOT USED
SWE
SWP
SWT
HME
BME
BMT
RESET:
1
MODCLK
0
0
0
0
SYPCR controls system monitor functions, software watchdog clock prescaling, and
bus monitor timing. This register can be written once following power-on or reset.
D
SWE — Software Watchdog Enable
0 = Software watchdog disabled
1 = Software watchdog enabled
SWP — Software Watchdog Prescale
0 = Software watchdog clock not prescaled
1 = Software watchdog clock prescaled by 512
SWT[1:0] — Software Watchdog Timing
This field selects software watchdog time-out period.
Table D-6 Software Watchdog Ratio
SWP
SWT
00
Ratio
9
0
0
0
0
1
1
1
1
2
11
01
2
13
10
2
15
11
2
18
00
2
20
01
2
22
10
2
24
11
2
HME — Halt Monitor Enable
0 = Disable halt monitor function
1 = Enable halt monitor function
MC68331
REGISTER SUMMARY
MOTOROLA
D-19
USER’S MANUAL
MOTOROLA [ MOTOROLA ]
