M34282M1 Datasheet, PDF (20/70 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

MITSUBISHI MICROCOMPUTERS
4282 Group
SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER
(4) Return signal
An external wakeup signal is used to return from the RAM
back-up mode. Table 8 shows the return condition for each
return source.
Table 8 Return source and return condition
Return source
Return condition
Remarks
Ports D4–D7
Return by an external “H” level Only key-on wakeup function of the port whose pull-down transistor is
input.
turned ON by register PU1 is valid.
Ports E0, E1, G
Return by an external “H” level Only key-on wakeup function of the port whose pull-down transistor is
input.
turned ON by register PU0 is valid.
Ports E2
Return by an external “H” level Key-on wakeup function is always valid.
input.
(5) Pull-down control register
Registers PU0 and PU1 are 4-bit registers and control the
ON/OFF of pull-down transistor and key-on wakeup function
for ports E0, E1, G and ports D4–D7.
Set the contents of register PU0 or PU1 through register A
with the TPU0A or TPU1A instruction, respectively.
Table 9 Pull-down control registers
Pull-down control register PU0
at reset : 00002
at RAM back-up : state retained
W
Ports G2, G3 pull-down transistor control 0 Pull-down transistor OFF, key-on wakeup invalid
PU03
bit
1 Pull-down transistor ON, key-on wakeup valid
Ports G0, G1 pull-down transistor control 0 Pull-down transistor OFF, key-on wakeup invalid
PU02
bit
1 Pull-down transistor ON, key-on wakeup valid
PU01 Port E1 pull-down transistor control bit
0 Pull-down transistor OFF, key-on wakeup invalid
1 Pull-down transistor ON, key-on wakeup valid
PU00 Port E0 pull-down transistor control bit
0 Pull-down transistor OFF, key-on wakeup invalid
1 Pull-down transistor ON, key-on wakeup valid
Pull-down control register PU1
PU13 Port D7 pull-down transistor control bit
PU12 Port D6 pull-down transistor control bit
PU11 Port D5 pull-down transistor control bit
PU10 Port D4 pull-down transistor control bit
Note: “W” represents write enabled.
at reset : 00002
at RAM back-up : state retained
W
0 Pull-down transistor OFF, key-on wakeup invalid
1 Pull-down transistor ON, key-on wakeup valid
0 Pull-down transistor OFF, key-on wakeup invalid
1 Pull-down transistor ON, key-on wakeup valid
0 Pull-down transistor OFF, key-on wakeup invalid
1 Pull-down transistor ON, key-on wakeup valid
0 Pull-down transistor OFF, key-on wakeup invalid
1 Pull-down transistor ON, key-on wakeup valid
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