R8CSLASH20 datasheet(391/501 Pages) RENESAS

391 / 501 page

R8C/20 Group, R8C/21 Group

19. Flash Memory

Rev.2.00 Aug 27, 2008

Page 375 of 458

REJ09B0250-0200

19. Flash Memory

19.1

Overview

In the flash memory version, rewrite operations to the flash memory can be performed in three modes

; CPU

rewrite, standard serial I/O, parallel I/O modes.

Table 19.1 lists the Flash Memory Performance (see Table 1.1 and Table 1.2 Performance for the items not listed

on Table 19.1).

NOTES:

1. Definition of programming and erasure endurance

The programming and erasure endurance is defined on a per-block basis.

If the programming and erasure endurance is n (n = 100 or 10,000), each block can be erased n

times. For example, if 1,024 1-byte writes are performed to different addresses in block A, a 1-Kbyte

block, and then the block is erased, the programming/erasure endurance still stands at one. When

performing 100 or more rewrites, the actual erasure endurance can be reduced by executing

programming operations in such a way that all blank areas are used before performing an erase

operation. Avoid rewriting only particular blocks and try to average out the programming and erasure

endurance of the blocks. It is also advisable to retain data on the erasure endurance of each block

and limit the number of erase operations to a certain number.

2. Blocks A and B are embedded only in the R8C/21 Group.

Table 19.1

Flash Memory Performance

Item

Specification

Flash Memory Operating Mode

3 modes (CPU rewrite, standard serial I/O, and parallel I/O mode)

Division of Erase Block

See Figure 19.1 and Figure 19.2

Program Method

Byte unit

Erase Method

Block erase

Program, Erase Control Method

Program and erase control by software command

Rewrite Control Method

Rewrite control for blocks 0 and 1 by FMR02 bit in FMR0 register

Rewrite control for block 0 by FMR16 bit and block 1 by FMR16 bit

Number of Commands

5 commands

Programming

and erase

endurance(1)

Blocks 0 and 1

(Program ROM)

R8C/20 Group: 100 times; R8C/21 Group: 1,000 times

Blocks A and B

(Data Flash)(2)

10,000 times

ID Code Check Function

Standard serial I/O mode supported

ROM Code Protect

For parallel I/O mode supported

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