UPD78F0537DGA(T)-9EV-A NEC, UPD78F0537DGA(T)-9EV-A Datasheet - Page 299

• 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

10.5 Cautions for Watch Timer
setting bits 0 (WTM0) and 1 (WTM1) of WTM to 1), the interval until the first interrupt request signal (INTWT) is
generated after the register is set does not exactly match the specification made with bits 2 and 3 (WTM2, WTM3) of
WTM. Subsequently, however, the INTWT signal is generated at the specified intervals.
Remark
When operation of the watch timer and 5-bit counter is enabled by the watch timer mode control register (WTM) (by
It takes 0.515625 seconds for the first INTWT to be generated (2
INTWT is then generated every 0.5 seconds.
Count clock
Watch timer
interrupt INTWT
Interval timer
interrupt INTWTI
Figure 10-4. Example of Generation of Watch Timer Interrupt Request Signal (INTWT)
f
Figures in parentheses are for operation with f
W
: Watch timer clock frequency
5-bit counter
WTM0, WTM1
Figure 10-3. Operation Timing of Watch Timer/Interval Timer
INTWT
Start
0H
Interrupt time of watch timer (0.5 s)
Interval time
(When Interrupt Period = 0.5 s)
(T)
CHAPTER 10 WATCH TIMER
0.515625 s
User’s Manual U17260EJ6V0UD
W
= 32.768 kHz (WTM7 = 1, WTM3, WTM2 = 0, 0)
0.5 s
Overflow
9
× 1/32768 = 0.015625 s longer).
Interrupt time of watch timer (0.5 s)
T
0.5 s
Overflow
299