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Rev.2.00 Nov 28, 2005 page 35 of 378
REJ09B0124-0200
M16C/6N Group (M16C/6NK, M16C/6NM) 5. Reset
Under development
This document is under development and its contents are subject to change.
5. Reset
Hardware reset, software reset, watchdog timer reset and oscillation stop detection reset are available to
reset the microcomputer.
5.1 Hardware Reset
____________
The microcomputer resets pins, the CPU and SFR by setting the RESET pin. If the supply voltage meets
the recommended operating conditions, the microcomputer resets all pins when an “L” signal is applied to
___________ ____________
the RESET pin (see Table 5.1 Pin Status When RESET Pin Level is “L”). The oscillation circuit is also
reset and the main clock starts oscillation. The microcomputer resets the CPU and SFR when the signal
____________
applied to the RESET pin changes low (“L”) to high (“H”). The microcomputer executes the program in an
address indicated by the reset vector. The internal RAM is not reset. When an “L” signal is applied to the
____________
RESET pin while writing data to the internal RAM, the internal RAM is in an indeterminate state.
Figure 5.1 shows an example of the reset circuit. Figure 5.2 shows a reset sequence. Table 5.1 lists pin
____________
states while the RESET pin is held low (“L”).
5.1.1 Reset on a Stable Supply Voltage
____________
(1) Apply “L” to the RESET pin
(2) Apply 20 or more clock cycles to the XIN pin
____________
(3) Apply “H” to the RESET pin
5.1.2 Power-on Reset
____________
(1) Apply “L” to the RESET pin
(2) Raise the supply voltage to the recommended operating level
(3) Insert td(P-R) ms as wait time for the internal voltage to stabilize
(4) Apply 20 or more clock cycles to the XIN pin
____________
(5) Apply “H” to the RESET pin
Figure 5.1 Example Reset Circuit
RESET
VCC
R
E
S
E
T
VCC
0
V
0
V
Supply a clock with td(P-R) +20
or more cycles to the XIN pin
0.2VCC or
below
0.2VCC or below
Re
c
o
m
m
e
n
d
e
d
operation
v
o
l
t
a
g
e
NOTE
1. Use the shortest possible wiring to connect external circuit.