16 STOPWATCH TIMER (SWT)
190
EPSON
S1C17001 TECHNICAL MANUAL
16.2 BCD Counters
The stopwatch counter consists of 1/100-second and 1/10-second 4-bit BCD counters.
The count value can be read from the SWT_BCNT register.
1/100-second counter
∗
BCD100[3:0]
: 1/100 Sec. BCD Counter Value in the Stopwatch Timer BCD Counter (SWT_BCNT) Register
(D[3:0]/0x5021)
1/10-second counter
∗
BCD10[3:0]
: 1/10 Sec. BCD Counter Value in the Stopwatch Timer BCD Counter (SWT_BCNT) Register
(D[7:4]/0x5021)
Count-up Pattern
A feedback division circuit is used to generate 100 Hz, 10 Hz, and 1 Hz signals from the 256 Hz clock. The
counter count-up pattern varies as shown in Figure 16.2.1.
3
256
2
256
3
256
2
256
3
256
2
256
3
256
2
256
3
256
2
256
1/100-second counter count-up pattern 1
256Hz
Approximate 100 Hz
(Feedback division circuit output)
1/100-second counter
Approximate 10 Hz
(1/100-second counter output)
Approximate 10 Hz
(1/100-second counter output)
1/10-second counter
1Hz
(1/10-second counter output)
25
256
1/100-second counter count-up pattern 2
seconds
26
256
×
6 + 25
256
×
4 = 1
second
26
256
seconds
26
256
seconds
25
256
seconds
25
256
seconds
26
256
seconds
26
256
seconds
25
256
seconds
25
256
seconds
26
256
seconds
26
256
seconds
seconds
26
256
3
256
3
256
3
256
2
256
3
256
2
256
3
256
2
256
3
256
2
256
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
1/10-second counter count-up pattern
Figure 16.2.1: Stopwatch timer count-up patterns
The feedback division circuit generates an approximate 100 Hz signal at 2/256-second and 3/256-second inter-
vals from the 256 Hz signal fed from the OSC module.
The 1/100-second counter counts the approximate 100 Hz signal output by the feedback division circuit and
generates an approximate 10 Hz signal at 25/256-second and 26/256-second intervals.
Count-up will be pseudo 1/100-second counting at 2/256-second and 3/256-second intervals.
The 1/10-second counter counts the approximate 10 Hz signal generated by the 1/100-second counter at a ratio
of 4:6, and generates a 1 Hz signal.
Count-up will be pseudo 1/10-second counting at 25/256-second and 26/256-second intervals.
Summary of Contents for S1C17001
Page 1: ...Technical Manual S1C17001 CMOS 16 BIT SINGLE CHIP MICROCONTROLLER ...
Page 33: ...4 POWER SUPPLY VOLTAGE 24 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 63: ...6 INITERRUPT CONTROLLER 54 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 87: ...8 CLOCK GENERATOR CLG 78 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 91: ...9 PRESCALER PSC 82 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 133: ...11 16 BIT TIMER T16 124 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 211: ...16 STOPWATCH TIMER SWT 202 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 219: ...17 WATCHDOG TIMER WDT 210 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 241: ...18 UART 232 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 277: ...20 I2 C 268 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 313: ...25 PACKAGE 304 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...