upd70f3017ay Renesas Electronics Corporation., upd70f3017ay Datasheet - Page 188

• Manufacturer Part Number: upd70f3017ay
• Description: V850/sa1tm 32-/16-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

(12) Edge detection
188
(a) When the TIn0 or TIn1 pin is high level immediately after a system reset
(b) Sampling clock for noise elimination
Remark
When the TIn0 or TIn1 pin is high level immediately after a system reset, if the valid edge of the TIn0 or TIn1
pin is specified as the rising edge or both rising and falling edges, and the operation of 16-bit timer/counter n
(TMn) is then enabled, the rising edge will be detected immediately. Care is therefore needed when the TIn0
or TIn1 pin is pulled up. However, when operation is enabled after being stopped, the rising or falling edge is
not detected.
The sampling clock for noise elimination differs depending on whether the TIn0 valid edge is used as a count
clock or a capture trigger. The former is sampled by f
selected using prescaler mode register n0 or n1 (PRMn0, PRMn1). Detecting the valid edge can eliminate
short pulse width noise because a capture operation is performed only after the valid edge is sampled and a
valid level is detected twice.
n = 0, 1
CHAPTER 7 TIMER/COUNTER FUNCTION
User’s Manual U12768EJ4V1UD
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/2, and the latter is sampled by the count clock