Renesas 16-bit single-chip microcomputer Manual De Usuario

Rev.1.02    Jul 01, 2005    page 239 of 314
REJ09B0126-0102

M16C/6N Group (M16C/6NL, M16C/6NN)

20. Flash Memory Version

This document is under development and its contents are subject to change.

Item

EW0 Mode

EW1 Mode

Operation Mode

• Single chip mode

Single chip mode

• Boot mode

Space where Rewrite

• User ROM area

User ROM area

Control Program can be

• Boot ROM area

Placed

Space where Rewrite

The rewrite control program must be The rewrite control program can be

Control Program can be

transferred to any space other than the

executed in the user ROM area

Executed

flash memory (e.g., RAM) before being

executed

 (2)

Space which can be

User ROM area

User ROM area

Rewritten

However, this excludes blocks with the

rewrite control program

Software Command

None

• Program and block erase commands

Restriction

cannot be executed in a block having

the rewrite control program.

• Erase all unlocked block command

cannot be executed when the lock bit in

a block having the rewrite control program

is set to “1” (unlocked) or when the

FMR02 bit in the FMR0 register is set

to “1” (lock bit disabled).

• Read status register command cannot

be used

Modes after Program or

Read status register mode

Read array mode

Erasing

CPU Status during Auto

Operating

Maintains hold state (I/O ports maintains

Write and Auto Erase

the state before the command was

 executed) 

(1)

Flash Memory Status

•Read the FMR00, FMR06 and FMR07 Read the FMR00, FMR06 and FMR07

Detection

 bits in the FMR0 register by program bits in the FMR0 register by program

•Execute the read status register

command to read the SR7, SR5, and

SR4 bits in the status register

In CPU rewrite mode, the user ROM area can be rewritten when the CPU executes software commands.

The user ROM area can be rewritten with the microcomputer is mounted on a board without using a parallel,

serial or CAN programmer.

In CPU rewrite mode, only the user ROM area shown in Figure 20.1 can be rewritten. The boot ROM area

cannot be rewritten. Program and the block erase command are executed only in the user ROM area.

Erase-write 0 (EW0) mode and erase-write 1 (EW1) mode are provided as CPU rewrite mode.

Table 20.3 lists the differences between EW0 and EW1 modes.

NOTES:

1.

_______

Do not generate an interrupts (except NMI and watchdog timer interrupts) and DMA transfer.

2. When in CPU rewrite mode, the PM10 and PM13 bits in the PM1 register are set to “1”. The rewrite

control program can only be executed in the internal RAM area.