4570 Datasheet, PDF (34/69 Pages) Renesas Technology Corp – SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

MITSUBISHI MICROCOMPUTERS
4570 Group
SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER
Reset
(Stabilizing time a )
A
POF instruction
is executed
f(XIN) oscillation
Return input
(Stabilizing time a )
B
f(XIN) stop
(RAM back-up
mode)
Stabilizing time a _{: The time required to stabilize f(XIN) oscillation is automatically}
generated by hardware.
Fig. 29 State transition
POF instruction
Reset input or voltage
drop detection circuit
output
Power down flag P
SQ
R
q Set source
q Clear source
POF instruction is executed
Reset input
Software start
P = “1” ^Yes
?
No
Cold start
Warm start
Fig. 30 Set source and clear source of the P flag
Fig. 31 Start condition identified example using the SNZP
instruction
Table 15 Key-on wakeup control register and pull-up control register
Key-on wakeup control register K0
at reset : 00002
at RAM back-up : state retained R/W
Port P43 key-on wakeup
K03 _{control bit}
Port P42 key-on wakeup
K02 _{control bit}
Port P41 key-on wakeup
K01 _{control bit}
Port P40 key-on wakeup
K00 _{control bit}
0 Key-on wakeup not used
1 Key-on wakeup used
0 Key-on wakeup not used
1 Key-on wakeup used
0 Key-on wakeup not used
1 Key-on wakeup used
0 Key-on wakeup not used
1 Key-on wakeup used
Pull-up control register PU0
at reset : 00002
at RAM back-up : state retained
Port P43 pull-up transistor
PU03 _{control bit}
0 Pull-up transistor OFF
1 Pull-up transistor ON
Port P42 pull-up transistor
PU02 _{control bit}
0 Pull-up transistor OFF
1 Pull-up transistor ON
Port P41 pull-up transistor
PU01 _{control bit}
0 Pull-up transistor OFF
1 Pull-up transistor ON
Port P40 and P01 pull-up transistor
PU00 _{control bit}
0 Pull-up transistor OFF
1 Pull-up transistor ON
Note: “R” represents read enabled, and “W” represents write enabled.
R/W
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