M38270E1-XXXFP View Datasheet(PDF) - MITSUBISHI ELECTRIC
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M38270E1-XXXFP
MITSUBISHI ELECTRIC
M38270E1-XXXFP Datasheet PDF : 70 Pages
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MITSUBISHI MICROCOMPUTERS
3827 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
Key Input Interrupt (Key-on wake-up)
A Key-on wake up interrupt request is generated by applying “L”
level to any pin of port P2 that have been set to input mode. In
other words, it is generated when AND of input level goes from “1”
to “0”. An example of using a key input interrupt is shown in Figure
16, where an interrupt request is generated by pressing one of the
keys consisted as an active-low key matrix which inputs to ports
P20–P23.
Port PXx
“L” level output
Port P27 output
PULLA register
Bit 2 = “1”
Key input control register = “1”
Port P27
direction register = “1”
V
VV Port P27
latch
V
Port P26 output
Key input control register = “1”
Port P26
direction register = “1”
VV Port P26
latch
V
Port P25 output
Key input control register = “1”
Port P25
direction register = “1”
VV Port P25
latch
V
Port P24 output
Key input control register = “1”
Port P24
direction register = “1”
VV Port P24
latch
V
Port P23
input
V
Port P22
input
V
Port P21
input
V
Port P20
input
Key input control register = “1”
Port P23
direction register = “0”
VV Port P23
latch
Key input control register = “1”
Port P22
direction register = “0”
VV Port P22
latch
Key input control register = “1”
Port P21
direction register = “0”
VV Port P21
latch
Key input control register = “1”
Port P20
direction register = “0”
VV Port P20
latch
Key input interrupt request
Port P2 input
reading circuit
V P-channel transistor for pull-up
VV CMOS output buffer
Fig. 16 Connection example when using key input interrupt and port P2 block diagram
20
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