3 wthr/wtmr/wtsr: hour/minute/second registers – FUJITSU MB91460 SERIES FR60 User Manual
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Chapter 49 Real-Time Clock
4.Registers
4.3 WTHR/WTMR/WTSR: Hour/Minute/Second Registers
These registers hold time information (HH/MM/SS) for Real-time Clock.
• WTHR (Hour register): Address 04A8
H
(Access: Byte, Half-word)
• WTMR (Minute register): Address 04A9
H
(Access: Byte, Half-word)
• WTSR (Second register): Address 04AA
H
(Access: Byte, Half-word)
• The values written to the hour/minute/second registers are the initial values to be loaded to the hour/
minute/second counters.
By setting “1” to the update bit (WTCR.UPDT) or the start bit (WTCR.ST), the hour/minute/second
register values are written to the hour/minute/second counters.
• The hour/minute/second counter values are saved to the hour/minute/second registers every time when
the second counter overflows, that is, at intervals of one minute. When the hour/minute/second counters
are read, the saved count values, not written ones, are read.
• The hour/minute/second registers consist of two separate sets of registers: one for reading and the other
for writing.
(See “
”.)
WTHR
7
6
5
4
3
2
1
0
bit
–
–
–
H4
H3
H2
H1
H0
–
–
–
X
X
X
X
X
Initial value
–
–
–
Unchanged Unchanged Unchanged Unchanged Unchanged
When reset
RX/WX
RX/WX
RX/WX
R,W
R,W
R,W
R,W
R,W
Attribute
WTMR
7
6
5
4
3
2
1
0
bit
–
–
M5
M4
M3
M2
M1
M0
–
–
X
X
X
X
X
X
Initial value
–
–
Unchanged Unchanged Unchanged Unchanged Unchanged Unchanged
When reset
RX/WX
RX/WX
R,W
R,W
R,W
R,W
R,W
R,W
Attribute
WTSR
7
6
5
4
3
2
1
0
bit
–
–
S5
S4
S3
S2
S1
S0
–
–
X
X
X
X
X
X
Initial value
–
–
Unchanged Unchanged Unchanged Unchanged Unchanged Unchanged
When reset
RX/WX
RX/WX
R,W
R,W
R,W
R,W
R,W
R,W
Attribute