M16C30P_07 Datasheet, PDF (43/317 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/30 SERIES

M16C/30P Group
5. Reset
5.4 Cold Start-up / Warm Start-up Determine Function
As for the cold start-up/warm start-up determine function, the WDC5 flag in the WDC register determines either
cold start-up (reset process) when power-on or warm start-up (reset process) when reset signal is applied during the
microcomputer running.
Default value of the WDC5 bit is “0” (cold start-up) when power-on. It is set to “1” (warm start-up) by writing
desired values to the WDC register. The WDC bit is not reset, regardless of a software reset or a reset operation.
Figure 5.4 shows Cold Start-up/Warm Start-up Determine Function Block Diagram. Figure 5.5 shows the Cold
Start-up/Warm Start-up Determine Function Operation Example. Figure 5.6 shows WDC Register.
Write to WDC register
Internal power on reset
WDC5 Bit
S
Q
R
WARM/COLD
(Cold start, warm start)
Figure 5.4 Cold Start-up/Warm Start-up Determine Function Block Diagram
5V
VCC
0V
5V
RESET
0V
“1”
WDC5 Flag
“0”
Pch transistor ON (about 4V)
CPU reset exited
T1
T2
Set to “1” by program
T > 100 µsec.
Program start
“1” is held even if
RESET becomes 0V.
Reset Sequence (16MHz, about 20 μsec.)
Becomes “0” on the rising
edge of VCC
NOTES:
1. The timing of which WDC5 is set is affected by how the RESET signal rises (Time lag between T1 and T2).
Figure 5.5 Cold Start-up/Warm Start-up Determine Function Operation Example
Rev.1.22 Mar 29, 2007 Page 27 of 291
REJ09B0179-0122