HD64F36024FX Datasheet, PDF (80/386 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 3 Exception Handling
Initial
Bit
Bit Name Value R/W Description
0
IWPF0 0
R/W WKP0 Interrupt Request Flag
[Setting condition]
When WKP0 pin is designated for interrupt input and the
designated signal edge is detected.
[Clearing condition]
When IWPF0 is cleared by writing 0.
3.3 Reset Exception Handling
When the RES pin goes low, all processing halts and this LSI enters the reset. The internal state of
the CPU and the registers of the on-chip peripheral modules are initialized by the reset. To ensure
that this LSI is reset at power-up, hold the RES pin low until the clock pulse generator output
stabilizes. To reset the chip during operation, hold the RES pin low for at least 10 system clock
cycles. When the RES pin goes high after being held low for the necessary time, this LSI starts
reset exception handling. The reset exception handling sequence is shown in figure 3.1.
The reset exception handling sequence is as follows. However, for the reset exception handling
sequence of the product with on-chip power-on reset circuit, refer to section 15, Power-On Reset
and Low-Voltage Detection Circuits (Optional).
1. Set the I bit in the condition code register (CCR) to 1.
2. The CPU generates a reset exception handling vector address (from H'0000 to H'0001), the
data in that address is sent to the program counter (PC) as the start address, and program
execution starts from that address.
Rev. 4.00 Sep. 23, 2005 Page 52 of 354
REJ09B0025-0400