UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 326

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

10.5 EXTERNAL EVENT COUNTER FUNCTION
count clock is specified as external clock input by the setting of the high-order 4 bits of prescaler mode register 1 (PRM1),
TM2 operates as an external event counter.
(f
and low level. If the pulse width is shorter than this, the pulse may not be counted.
(1) Counting one edge (maximum frequency = f
286
CLK
Timer/counter 2 can count clock pulses input from external interrupt request input pin (INTP2/CI).
No special selection method is needed for the external event counter operating mode. When the timer register 2 (TM2)
The maximum frequency of external clock pulses that can be counted by TM2 as the external event counter is 1.56 MHz
The pulse width of INTP2/CI input must be at least 4 system clocks (0.32 s: f
The timer/counter 2 external event count timing is shown in Figure 10-11.
Remark ICI: CI input signal after passing through edge detection circuit
= 12.5 MHz) irrespective of whether only one edge or both edges are counted on INTP2/CI input.
TM2
ICI
CI
4/f
Dn
CLK
Figure 10-11 Timer/Counter 2 External Event Count Timing (1/2)
(MIN.) 4/f
CLK
(MIN.) 8/f
Dn+1
CHAPTER 10 TIMER/COUNTER 2
CLK
(MIN.)
CLK
/8)
Dn+2
3–4/f
CLK
Dn+3
CLK
= 12.5 MHz) for both the high level