HD64F2149YV datasheet(738/1075 Pages) RENESAS

738 / 1075 page

Section 22 ROM

Rev. 3.00 Jan 18, 2006 page 710 of 1044

REJ09B0280-0300

Branch to flash memory application

program

Branch to program/erase control

program in RAM area

Execute program/erase control

program (flash memory rewriting)

Transfer program/erase control

program to RAM

MD1, MD0 = 10, 11

Reset-start

Write the transfer program

(and the program/erase control program

if necessary) beforehand

Note: The watchdog timer should be activated to prevent overprogramming or overerasing

due to program runaway, etc.

Figure 22.11 User Program Mode Execution Procedure

22.7

Programming/Erasing Flash Memory

In the on-board programming modes, flash memory programming and erasing is performed by

software, using the CPU. There are four flash memory operating modes: program mode, erase

mode, program-verify mode, and erase-verify mode. Transitions to these modes can be made by

setting the PSU and ESU bits in FLMCR2, and the P, E, PV, and EV bits in FLMCR1.

The flash memory cannot be read while being programmed or erased. Therefore, the program that

controls flash memory programming/erasing (the programming control program) should be

located and executed in on-chip RAM or external memory.

Notes: 1. Operation is not guaranteed if setting/resetting of the SWE, EV, PV, E, and P bits in

FLMCR1, and the ESU and PSU bits in FLMCR2, is executed by a program in flash

memory.

2. Perform programming in the erased state. Do not perform additional programming on

previously programmed addresses.

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