UPD78F0537DGA(T)-9EV-A NEC, UPD78F0537DGA(T)-9EV-A Datasheet - Page 298

• Manufacturer Part Number: UPD78F0537DGA(T)-9EV-A
• Description: 8BIT MCU, 128K FLASH, 7KB RAM, SMD
• Manufacturer: NEC

Specifications of UPD78F0537DGA(T)-9EV-A

• Controller Family/series: UPD78
• No. Of I/o's: 55
• Ram Memory Size: 7KB
• Cpu Speed: 20MHz
• No. Of Timers: 8
• No. Of Pwm: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 128KB
• Oscillator Type: External, Internal

10.4 Watch Timer Operations
10.4.1 Watch timer operation
hardware clock or subsystem clock.
operation starts. When these bits are cleared to 0, the 5-bit counter is cleared and the count operation stops.
clearing WTM1 to 0. In this case, however, the 11-bit prescaler is not cleared. Therefore, an error up to 2
seconds occurs in the first overflow (INTWT) after zero-second start.
Remarks 1. f
10.4.2 Interval timer operation
interval of the preset count value.
(WTM).
stops.
Remarks 1. f
298
WTM6
WTM3
The watch timer generates an interrupt request signal (INTWT) at a specific time interval by using the peripheral
When bit 0 (WTM0) and bit 1 (WTM1) of the watch timer operation mode register (WTM) are set to 1, the count
When the interval timer is simultaneously operated, zero-second start can be achieved only for the watch timer by
The interrupt request is generated at the following time intervals.
The watch timer operates as interval timer which generates interrupt request signals (INTWTI) repeatedly at an
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
0
0
0
0
1
1
1
1
0
0
1
1
WTM5
WTM2
2. f
3. f
2. f
3. f
0
0
1
1
0
0
1
1
0
1
0
1
W
PRS
SUB
W
PRS
SUB
:
:
WTM4
Interrupt Time
2
2
2
2
: Peripheral hardware clock frequency
: Subsystem clock frequency
: Peripheral hardware clock frequency
: Subsystem clock frequency
14
13
5
4
/f
/f
Watch timer clock frequency (f
Watch timer clock frequency (f
0
1
0
1
0
1
0
1
Selection
/f
/f
W
W
W
W
2
2
2
2
2
2
2
2
Interval Time
4
5
6
7
8
9
10
11
/f
/f
/f
/f
/f
/f
/f
/f
W
W
W
W
W
W
W
W
When Operated at
f
0.5 s
0.25 s
977
488
SUB
(WTM7 = 1)
= 32.768 kHz
µ
µ
s
s
Table 10-4. Watch Timer Interrupt Time
Table 10-5. Interval Timer 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
CHAPTER 10 WATCH TIMER
µ
µ
s
s
User’s Manual U17260EJ6V0UD
= 32.768
When Operated at
1.05 s
0.52 s
2.05 ms
1.02 ms
PRS
PRS
f
(WTM7 = 0)
PRS
/2
/2
7
7
= 2 MHz
or f
or f
When Operated
1.02 ms
2.05 ms
4.10 ms
8.20 ms
16.4 ms
32.8 ms
65.5 ms
131.1 ms
at f
(WTM7 = 0)
SUB
PRS
SUB
)
= 2 MHz
)
When Operated at
0.419 s
0.210 s
819
410
f
(WTM7 = 0)
PRS
µ
µ
s
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
= 5 MHz
(WTM7 = 0)
PRS
µ
µ
s
s
= 5 MHz
When Operated at
0.210 s
0.105 s
410
205
f
PRS
(WTM7 = 0)
at f
When Operated
205
410
820
1.64 ms
3.28 ms
6.55 ms
13.1 ms
26.2 ms
µ
µ
(WTM7 = 0)
s
s
= 10 MHz
PRS
µ
µ
µ
s
s
s
= 10 MHz
When Operated at
0.105 s
52.5 ms
205
102
at f
When Operated
f
102
205
410
820
1.64 ms
3.28 ms
6.55 ms
13.1 ms
PRS
(WTM7 = 0)
(WTM7 = 0)
µ
µ
PRS
= 20 MHz
s
s
µ
µ
µ
µ
s
s
s
s
= 20 MHz
9
× 1/f
W