h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 150

• Manufacturer Part Number: h8s-2138
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 4 Exception Handling
4.2.3
If an interrupt is accepted after a reset but before the stack pointer (SP) is initialized, the PC and
CCR will not be saved correctly, leading to a program crash. To prevent this, all interrupt requests,
including NMI, are disabled immediately after a reset. Since the first instruction of a program is
always executed immediately after the reset state ends, make sure that this instruction initializes
the stack pointer (example: MOV.L #xx:32, SP).
Rev. 4.00 Jun 06, 2006 page 96 of 1004
REJ09B0301-0400
RES
Address bus
RD
WR
D7 to D0
(1) (3) Reset exception vector address ((1) = H'0000, (3) = H'0001)
(2) (4) Start address (contents of reset exception vector address)
(5)
(6)
Note: * 3 program wait states are inserted.
Interrupts after Reset
Start address ((5) = (2) (4))
First program instruction
Figure 4.3 Reset Sequence (Mode 1)
*
(1)
Vector fetch
(2)
High
*
(3)
Internal
processing
(4)
Fetch of
first program
instruction
(5)
*
(6)