38K0 Datasheet, PDF (82/133 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

38K0 Group
(1) CPU Rewrite Mode
In CPU rewrite mode, the internal flash memory can be operated
on (read, program, or erase) under control of the Central Process-
ing Unit (CPU).
In CPU rewrite mode, only the User ROM area shown in Figure
116 can be rewritten; the Boot ROM area cannot be rewritten.
Make sure the program and block erase commands are issued for
only the User ROM area and each block area.
The control program for CPU rewrite mode can be stored in either
User ROM or Boot ROM area. In the CPU rewrite mode, because
the flash memory cannot be read from the CPU, the rewrite con-
trol program must be transferred to internal RAM area to be
executed before it can be executed.
Microcomputer Mode and Boot Mode
The control program for CPU rewrite mode must be written into
the User ROM or Boot ROM area in parallel I/O mode beforehand.
(If the control program is written into the Boot ROM area, the stan-
dard serial I/O mode becomes unusable.)
See Figure 116 for details about the Boot ROM area.
Normal microcomputer mode is entered when the microcomputer
is reset with pulling CNVSS pin low. In this case, the CPU starts
operating using the control program in the User ROM area.
When the microcomputer is reset by pulling the P16 (CE) pin high,
the CNVSS pin high, the CPU starts operating using the control
program in the Boot ROM area. This mode is called the “Boot”
mode.
Block Address
Block addresses refer to the maximum address of each block.
These addresses are used in the block erase command.
User ROM area
800016
Block 1 : 32 Kbytes
FFFF16
Boot ROM area
F00016
FFFF16
4 Kbytes
Notes 1: The Boot ROM area can be rewritten in only parallel I/O mode. (Access to any other
areas is inhibited.)
2: To specify a block, use the maximum address in the block.
Fig. 116 Block diagram of built-in flash memory
Rev.3.00 Oct 05, 2006 page 82 of 129
REJ03B0192-0300