mc68hc916y3 Freescale Semiconductor, Inc, mc68hc916y3 Datasheet - Page 394

• Manufacturer Part Number: mc68hc916y3
• Description: Mc68hc16y3 16 Bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

D.2.18 Software Watchdog Service Register
SWSR — Software Watchdog Service Register
D.2.19 Port F Edge-Detect Flag Register
PORTFE — Port F Edge-Detect Flag Register
D-16
MOTOROLA
NOTES:
15
15
RESET:
RESET:
The following equation calculates the PIT period when a fast reference frequency is
used:
The following equation calculates the PIT period for an externally input clock
frequency on both slow and fast reference frequency devices.
1. This register is shown with a read value.
This register can be read or written at any time. Bits [15:8] are unimplemented and will
always read zero.
To reset the software watchdog:
Both writes must occur in the order specified before the software watchdog times out,
but any number of instructions can occur between the two writes.
1. Write $55 to SWSR.
2. Write $AA to SWSR.
14
13
PIT Period
PIT Period
PIT Period
12
NOT USED
NOT USED
Freescale Semiconductor, Inc.
11
For More Information On This Product,
=
------------------------------------------------------------------------------------------------------------------------------------ -
10
=
=
128 PITM[7:0] 1 if PTP = 0, 512 if PTP = 1 4
---------------------------------------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------------------------------------
Go to: www.freescale.com
PITM[7:0] 1 if PTP = 0, 512 if PTP = 1 4
PITM[7:0] 1 if PTP = 0, 512 if PTP = 1 4
REGISTER SUMMARY
9
8
8
PEF7
7
0
7
0
1
EF6
6
0
6
0
f
f
f
sys
ref
ref
5
0
5
0
4
SWSR[7:0]
0
4
0
RESERVED
3
0
3
0
MC68HC16Y3/916Y3
USER’S MANUAL
2
0
2
0
$YFFA26
$YFFA28
1
0
1
0
PEF0
0
0
0
0