HD6412240 RENESAS [Renesas Technology Corp], HD6412240 Datasheet - Page 139

• Manufacturer Part Number: HD6412240
• Description: Renesas 16-Bit Single-Chip Microcomputer H8S Family / H8S/2200 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

A reset caused by the watchdog timer can also be of either of two types: a power-on reset or a
manual reset.
4.2.3
The H8S/2245 Group enters the reset state when the RES pin goes low.
To ensure that the H8S/2245 Group is reset, hold the RES pin low for at least 20 ms at power-up.
To reset the H8S/2245 Group during operation, hold the RES pin low for at least 20 states. See
appendix D.1, Port States in Each Mode.
When the RES pin goes high after being held low for the necessary time, the H8S/2245 Group
starts reset exception handling as follows:
1. The internal state of the CPU and the registers of the on-chip supporting modules are
2. The reset exception handling vector address is read and transferred to the PC, and program
Figures 4.2 and 4.3 show examples of the reset sequence.
initialized, and the I bit is set to 1 in CCR.
execution starts from the address indicated by the PC.
Reset Sequence
RES
Internal
address bus
Internal read
signal
Internal write
signal
Internal data
bus
(1) Reset exception handling vector address ((1) = H'0000)
(2) Start address (contents of reset exception handling vector address)
(3) Start address ((3) = (2))
(4) First program instruction
Figure 4.2 Reset Sequence (Modes 2 and 3)
Vector
fetch
(1)
(2)
Internal
processing
High
Rev.3.00 Mar. 26, 2007 Page 97 of 772
Fetch of first program
instruction
(3)
Section 4 Exception Handling
(4)
REJ09B0355-0300