SIC63616-(Rev. 1.0) NO. P88
3240-0412
The stopwatch timer sets the 1 Hz interrupt factor flag ISW1 to "1" when requiring a carry-up to 1-sec
digit by an SWD8–11 overflow. If the capture buffer shifts into hold status (when SWD0–3 is read or
when LAP is input) while the 1 Hz interrupt factor flag ISW1 is set to "1", the lap data carry-up request
flag LCURF is set to "1" to indicate that a carry-up to 1-sec digit is required for the processing of LAP
input. In normal software processing, LAP processing may take precedence over 1-sec or higher digits
processing by a 1 Hz interrupt, therefore carry-up processing using this flag should be used for time dis-
play in the LAP processing to prevent the 1-sec digit data decreasing by 1 second. This flag is renewed
when the capture buffer shifts into hold status.
Figure 4.8.6.2 shows the operating timing for the direct LAP input, and Figure 4.8.6.3 shows the timings
for data holding and reading during a direct LAP input and reading.
f
OSC1
/32 (1,024 Hz)
Direct LAP input (P11/P10)
Direct LAP internal signal
Data holding
Direct LAP interrupt
SWD8–11 reading
Fig. 4.8.6.2 Operating timing for direct LAP input
Direct LAP input (P11/P10)
Capture renewal flag CRNWF
SWD0–3 reading
SWD4–7 reading
SWD8–11 reading
Data holding
1 Hz interrupt factor flag ISW1
Lap data carry-up request flag LCURF
Counter data
999
000
Fig. 4.8.6.3 Timing for data holding and reading during direct LAP input
Key mask
In stopwatch applications, some functions may be controlled by a combination of keys including direct
RUN or direct LAP. For instance, the RUN key can be used for other functions, such as reset and setting
a watch, by pressing the RUN key with another key. In this case, the direct RUN function or direct LAP
function must be invalid so that it does not function. For this purpose, the key mask function is set so
that it judges concurrence of input keys and invalidates RUN and LAP functions. A combination of the
key inputs for this judgment can be selected using the DKM0–DKM2 registers.
Table 4.8.6.2 Key mask selection
DKM2
0
0
0
0
1
1
1
1
DKM1
0
0
1
1
0
0
1
1
DKM0
0
1
0
1
0
1
0
1
Mask key combination
None (at initial reset)
P12
P12, P13
P12, P13, P40
P40
P40, P41
P40, P41, P42
P40, P41, P42, P43
Содержание S1C63616
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