UPD78F0890GK(A)-GAJ-AX NEC, UPD78F0890GK(A)-GAJ-AX Datasheet - Page 270

• Manufacturer Part Number: UPD78F0890GK(A)-GAJ-AX
• Description: 8BIT MCU, 128K FLASH, 7K RAM, LQFP
• Manufacturer: NEC

Specifications of UPD78F0890GK(A)-GAJ-AX

• Controller Family/series: UPD78F
• No. Of I/o's: 55
• Ram Memory Size: 7KB
• Cpu Speed: 20MHz
• No. Of Timers: 10
• No. Of Pwm: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 128KB
• Oscillator Type: External, Internal

10.4.2 Interval timer operation
the preset count value.
(WTM).
stops.
Remarks 1. f
270
WTM6
The watch timer operates as interval timer which generates interrupt requests (INTWTI) repeatedly at an interval of
The interval time can be selected with bits 4 to 6 (WTM4 to WTM6) of the watch timer operation mode register
When bit 0 (WTM0) of the WTM is set to 1, the count operation starts. When this bit is set to 0, the count operation
Remark
0
0
0
0
1
1
1
1
Count clock
Watch timer
interrupt INTWT
Interval timer
interrupt INTWTI
WTM5
2. f
3. f
0
0
1
1
0
0
1
1
f
Figures in parentheses are for operation with f
W
W
PRS
SUB
: Watch timer clock frequency
:
WTM4
: Peripheral hardware clock frequency
: Subsystem clock frequency
5-bit counter
Watch timer clock frequency (f
0
1
0
1
0
1
0
1
2
2
2
2
2
2
2
2
Interval Time
Figure 10-3. Operation Timing of Watch Timer/Interval Timer
4
5
6
7
8
9
10
11
/f
/f
/f
/f
/f
/f
/f
/f
W
W
W
W
W
W
W
W
Start
0H
Table 10-5. Interval Timer Interval Time
Interrupt time of watch timer (0.5 s)
Interval time
kHz (WTM7 = 1)
488
977
1.95 ms
3.91 ms
7.81 ms
15.6 ms
31.3 ms
62.5 ms
When Operated
at f
SUB
(T)
CHAPTER 10 WATCH TIMER
μ
μ
s
s
User’s Manual U17554EJ4V0UD
= 32.768
PRS
/2
7
or f
When Operated
0.51 ms
1.03 ms
2.05 ms
4.1 ms
8.2 ms
16.4 ms
32.75 ms
65.55 ms
at f
(WTM7 = 0)
PRS
SUB
W
= 32.768 kHz (WTM7 = 1, WTM3, WTM2 = 0, 0)
= 4 MHz
)
Overflow
Interrupt time of watch timer (0.5 s)
When Operated
410
820
1.64 ms
3.28 ms
6.55 ms
13.1 ms
26.2 ms
52.4 ms
at f
(WTM7 = 0)
PRS
μ
μ
s
s
T
= 5 MHz
at f
When Operated
205
410
820
1.64 ms
3.28 ms
6.55 ms
13.1 ms
26.2 ms
(WTM7 = 0)
PRS
μ
μ
μ
s
s
s
= 10 MHz
Overflow
at f
When Operated
102
205
410
820
1.64 ms
3.28 ms
6.55 ms
13.1 ms
(WTM7 = 0)
PRS
μ
μ
μ
μ
s
s
s
s
= 20 MHz