M38503MXH Datasheet, PDF (33/86 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 20 cycles or more of XIN. 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 reset 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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