
Microcomputer Technical Q&A
136
Q&A No.: QAH8S-248
Category: I/O Ports
Subject: Disabling
φ
Output
Question
Is there any way of fixing
φ
output high in normal operation?
Answer
Yes. To fix
φ
output high, set the PSTOP bit to 1 in the system clock control register (SCKCR)
(see table below). Also,
φ
output can be disabled by clearing the corresponding port data direction
register (DDR) bit to 0, designating input port operation.
Disabling or fixing
φ
output is effective in reducing peripheral noise, current dissipation, etc.
φ
Pin States in Each Processing State
DDR 0 1
PSTOP — 0 1
Hardware standby mode High impedance High impedance High impedance
Software standby mode High impedance Fixed high Fixed high
Sleep mode High impedance
φ
output Fixed high
Normal operating state High impedance
φ
output Fixed high
Applicable Products
Applicability Series Applicability Series Applicability Series
Entire H8S Series Yes H8S/2655 Yes H8S/2350
Yes H8S/2355 Yes H8S/2357 Yes H8S/2345
Yes H8S/2245 H8S/2148 H8S/2144
H8S/2138 H8S/2134 H8S/2128
H8S/2124 — — — —
Comentarios a estos manuales