Datasheet

Section 23 ROM (H8S/2148 F-ZTAT A-Mask Version, H8S/2147 F-ZTAT A-Mask Version, H8S/2144 F-ZTAT A-Mask Version)
Rev. 4.00 Sep 27, 2006 page 690 of 1130
REJ09B0327-0400
23.4.3 Flash Memory Operating Modes
Mode Transitions
When the mode pins are set in the reset state and a reset-start is executed, the MCU enters one of
the operating modes shown in figure 23.3. In user mode, flash memory can be read but not
programmed or erased.
Flash memory can be programmed and erased in boot mode, user program mode, and programmer
mode.
Boot mode
On-board programming mode
User
program mode
User mode with
on-chip ROM
enabled
Reset state
Programmer
mode
RES = 0
SWE = 1
SWE = 0
*
1
*
2
Notes: Only make a transition between user mode and user program mode when the CPU is
not accessing the flash memory.
1. MD0 = MD1 = 0, P92 = P91 = P90 = 1
2. MD0 = MD1 = 0, P92 = 0, P91 = P90 = 1
RES = 0
RES = 0
RES = 0
MD1 = 1
Figure 23.3 Flash Memory Mode Transitions