UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 289

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

CHAPTER 9 TIMER/COUNTER 1
Caution When timer/counter 1 is used as an external event counter, it is not possible to distinguish between the
case where there is no valid edge input at all and the case where there is a single valid edge input using
the timer register 1 (TM1) alone (see Figure 9-11), since the contents of TM1 are 0 in both cases. If it is
necessary to make this distinction, the INTP0 interrupt request flag should be used. An example is shown
in Figure 9-12.
Figure 9-11 Example of the Case Where the External Event Counter Does Not Distinguish Between One
Valid Edge Input and No Valid Edge Input
INTP0
TM1
0
0
1
2
No Distinction Made
Count Start
249