10 STOPWaTCh TiMeR
S1C63003/004/008/016 TeChniCal Manual
Seiko epson Corporation
10-5
(Rev. 1.1)
Direct LAP input (P01/P00)
Capture renewal flag CRNWF
SWD[3:0] reading
SWD[7:4] reading
SWD[11:8] reading
Data holding
1 Hz interrupt factor flag ISW1
Lap data carry-up request flag LCURF
Counter data
999
000
6.3 Timing for data holding and reading during direct LAP input
Figure 10.
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 press-
ing 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 DKM[2:0] register.
6.2 Key mask selection
Table 10.
DKM[2:0]
Mask key combination
0H
None (at initial reset)
1H
P02
2H
P02, P03
3H
P02, P03, P10
4H
P10
5H
P10, P11
6H
P10, P11, P12
7H
P10, P11, P12, P13
RUN or LAP inputs become invalid in the following status.
1. The RUN or LAP key is pressed when one or more keys that are included in the selected combination (here
in after referred to as mask) are held down.
2. The RUN or LAP key has been pressed when the mask is released.
f
OSC1
/32 (1,024 Hz)
Direct RUN/LAP input
Key mask
valid
invalid
invalid
invalid
6.4 Operation of key mask
Figure 10.
RUN or LAP inputs become valid in the following status.
1. Either the RUN or LAP key is pressed independently if no other key is been held down.
2. Both the RUN and LAP keys are pressed at the same time if no other key is held down. (RUN and LAP
functions are effective.)
3. The RUN or LAP key is pressed if either is held down. (RUN and LAP functions are effective.)
4. Either the RUN or LAP key and the mask key are pressed at the same time if no other key is held down.
5. Both the RUN and LAP keys and the mask key are pressed at the same time if no other key is held down. (RUN
and LAP functions are effective.)
* Simultaneous key input is referred to as two or more key inputs are sampled at the same falling edge of 1,024
Hz clock.