M16C30P_07 Datasheet, PDF (39/317 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/30 SERIES

M16C/30P Group
5. Reset
5. Reset
Hardware reset and software 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 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 an “H” signal 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
RESET
VCC1
Recommended
operating voltage
VCC1
0V
RESET
0V
0.2VCC1
or below
NOTES :
1. Use the M16C/30P on VCC1=VCC2.
Figure 5.1 Example Reset Circuit
0.2VCC1 or below
Supply a clock with td(P-R) + 20
or more cycles to the XIN pin
Rev.1.22 Mar 29, 2007 Page 23 of 291
REJ09B0179-0122