UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 227

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

8.5 EXTERNAL EVENT COUNTER FUNCTION
clock is specified as external clock input by the setting of the low-order 4 bits of prescaler mode register 0 (PRM0), TM0 operates
as an external event counter.
= 12.5 MHz) irrespective of whether only one edge or both edges are counted on INTP3 input.
low level. If the pulse width is shorter than this, the pulse may not be counted.
(1) Counting one edge (maximum frequency = f
The timer/counter 0 can count clock pulses input from the external interrupt request input pin (INTP3).
No special selection method is needed for the external event counter operating mode. When the timer register 0 (TM0) count
The maximum frequency of external clock pulses that can be counted by TM0 as the external event counter is 1.56 MHz (f
The pulse width of the INTP3 input must be at least 4 system clocks (0.32 s: f
The timer/counter 0 external event counter timing is shown in Figure 8-10.
INTP3
Remark
TM0
ICI
ICI: INTP3 input signal after passing through edge detection circuit
4/f
Dn
CLK
(MIN.) 4/f
Figure 8-10 Timer/Counter 0 External Event Count Timing (1/2)
CLK
(MIN.)
Dn+1
8/f
CHAPTER 8 TIMER/COUNTER 0
CLK
CLK
(MIN.)
/8)
Dn+2
3–4/f
CLK
CLK
= 12.5 MHz) for both the high level and
Dn+3
187
CLK