M68HC16 Z SERIES
REGISTER SUMMARY
USER’S MANUAL
D-15
D.2.15 Software Watchdog Service Register
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:
1. Write $55 to SWSR.
2. Write $AA to SWSR.
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.
D.2.16 Port C Data Register
This register latches data for chip-select pins configured as discrete outputs. This reg-
ister can be read or written at any time. Bits [15:8] are unimplemented and will always
read zero.
D.2.17 Chip-Select Pin Assignment Registers
Chip-select pin assignment registers configure the chip-select pins for discrete I/O, an
alternate function, or as an 8-bit or 16-bit chip-select. The possible encodings for each
2-bit field in CSPAR[0:1] (except for CSBTPA[1:0]) are shown in
SWSR — Software Watchdog Service Register
1
$YFFA26
NOTES:
1. This register is shown with a read value.
15
8
7
6
5
4
3
2
1
0
NOT USED
SWSR[7:0]
RESET:
0
0
0
0
0
0
0
0
PORTC — Port C Data Register
$YFFA40
15
8
7
6
5
4
3
2
1
0
NOT USED
0
PC6
PC5
PC4
PC3
PC2
PC1
PC0
RESET:
0
1
1
1
1
1
1
1
CSPAR0 — Chip-Select Pin Assignment Register 0
$YFFA44
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
0
CS5PA[1:0]
CS4PA[1:0]
CS3PA[1:0]
CS2PA[1:0]
CS1PA[1:0]
CS0PA[1:0]
CSBTPA[1:0]
RESET:
0
0
DATA2
1
DATA2
1
DATA2
1
DATA1
1
DATA1
1
DATA1
1
1
DATA0
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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