Wd clock mode register, Wd control register – Rainbow Electronics AT75C220 User Manual
Page 142
AT75C220
142
WD Clock Mode Register
Name:
WD_CMR
Access:
Read/write
Reset Value:0
•
WDCLKS: Clock Selection
•
HPCV: High Preload Counter Value
Counter is preloaded when watchdog counter is restarted with bits 0 to 11 set (FFF) and bits 12 to 15 equaling HPCV.
•
CKEY: Clock Access Key
Used only when writing WD_CMR. CKEY is read as 0.
0x06E: Write access in WD_CMR is allowed.
Other value: Write access in WD_CMR is prohibited.
WD Control Register
Name:
WD_CR
Access:
Write-only
•
RSTKEY: Restart Key
0xC071 = Watchdog counter is restarted.
Other value = No effect.
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
CKEY
7
6
5
4
3
2
1
0
CKEY
–
HPCV
WDCLKS
WDCLKS
Clock Selected
0
0
ACLK/8
0
1
ACLK/32
1
0
ACLK/128
1
1
ACLK/1024
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
RSTKEY
7
6
5
4
3
2
1
0
RSTKEY