CHAPTER 14 PORT FUNCTION
User’s Manual U13850EJ4V0UM
377
Cautions 1. If the input pulse width is 2 or 3 clock, whether it will be detected as a valid edge or
eliminated as noise is undermined.
2. To ensure correct detection of pulses as pulses, constant-level input is required for 3
clocks or more.
3. If noise is occurring in synchronization with the sampling clock, it may not be
recognized as noise. In such cases, attach a filter to the input pins to eliminate the
noise.
4. Noise elimination is not performed when these pins are used as an ordinary input
port.
(3) Control registers
(a) Port 0 mode register (PM0)
PM0 can be read/written in 8-/1-bit units.
Figure 14-2. Port 0 Mode Register (PM0)
After reset:
FFH
R/W
Address: FFFFF020H
7
6
5
4
3
2
1
0
PM0
PM07
PM06
PM05
PM04
PM03
PM02
PM01
PM00
PM0n
Control of I/O mode (n = 0 to 7)
0
Output mode
1
Input mode
(b) Pull-up resistor option register 0 (PU0)
PU0 can be read/written in 8-/1-bit units.
Figure 14-3. Pull-Up Resistor Option Register 0 (PU0)
After reset:
00H
R/W
Address: FFFFF080H
7
6
5
4
3
2
1
0
PU0
PU07
PU06
PU05
PU04
PU03
PU02
PU01
PU00
PU0n
Control of on-chip pull-up resistor connection (n = 0 to 7)
0
Do not connect
1
Connect
Содержание MPD703030A
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