M16C6KA_15 Datasheet, PDF(238/270 Page) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER Description

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M16C6KA_15 Datasheet, PDF (238/270 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER Description

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M16C/6KA Group

CPU Reprogram Mode

CPU reprogram mode

In CPU reprogram mode, the on-chip flash memory can be operated on (read, program or erase) under the

control of CPU.

In CPU reprogram mode, only the user ROM area shown in Fig.AB-1 can be reprogrammed. The boot ROM

area cannot be reprogrammed. Make sure the program and block erase commands are issued only for each

block of the user ROM area.

There are erase write mode 0 (EW0 mode) and erase write mode 1 (EW1 mode) in CPU reprogram mode.

Table BB-1 shows the difference between EW0 mode and EW1 mode.

EW0 mode

The microcomputer is placed in CPU rewrite mode by setting the FMR0 register's FMR01 bit to "1" (CPU

reprogram mode enabled), ready to accept commands. In this case, because the FMR1 register's FMR11

bit=0, EW0 mode is selected. The FMR01 bit can be set to "1" by writing "0" and then "1" in succession. Use

software commands to control program and erase operations. Read the FMR0 register or status register to

check the status of program or erase operation completion.

EW1 mode

EW1 mode is selected by setting FMR11 bit to "1" (by writing "0" and then "1" in succession) after setting the

FMR01 bit to "1" (by writing "0" and then "1" in succession).

Read the FMR0 register to check the status of program or erase operation at completion. The status register

can not be read during EW1 mode.

Microcomputer mode and Boot mode

The control program for CPU reprogram 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 standard serial I/

O mode becomes disable.)

See Fig.AB-1 for details about the boot ROM area.

Normal microcomputer mode is entered when reset with pulling âLâ of M0. In this case, the CPU starts

operating the control program in user ROM area.

If the microcomputer is reset with M0 being âHâ and M1 being âLâ, the CPU starts operating the control

program in boot ROM area. This mode is called as âbootâ mode.

Block address

Block address refers to the maximum even address of each block. The address is used in block erase

command.

Rev.1.00 Jul 16, 2004 page 236 of 266

REJ03B0100-0100Z

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