M38503M4H Datasheet, PDF (33/51 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

RESET CIRCUIT
To reset the microcomputer, RESET pin must be held at an "L"
level for 2 µs or more. Then the RESET pin is returned to an "H"
level (the power source voltage must be between 2.7 V and 5.5 V,
and the oscillation must be stable), reset is released. After the re-
set is completed, the program starts from the address contained in
address FFFD16 (high-order byte) and address FFFC16 (low-order
byte). Make sure that the reset input voltage is less than 0.54 V for
VCC of 2.7 V.
MITSUBISHI MICROCOMPUTERS
3850 Group (Spec. H)
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
RESET
Power source
VCC ^voltage
0V
Reset input
voltage
0V
Poweron
(Note)
0.2VCC
Note : Reset release voltage ; Vcc=2.7 V
RESET
VCC
Power source
voltage detection
circuit
Fig. 36 Reset circuit example
XIN
φ
RESET
RESETOUT
Address
Data
SYNC
?
?
?
?
FFFC FFFD ADH,L
Reset address from the vector table.
?
?
?
?
ADL
ADH
XIN: 8 to 13 clock cycles
Notes 1: The frequency relation of f(XIN) and f(φ) is f(XIN) = 2 • f(φ).
2: The question marks (?) indicate an undefined state that depends on the previous state.
3: All signals except XIN and RESET are internals.
Fig. 37 Reset sequence
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