18. Flash Memory; Overview - Renesas R8C Series User Manual

R8C/1A Group, R8C/1B Group

18. Flash Memory

18.1

Overview

In the flash memory, rewrite operations to the flash memory can be performed in three modes; CPU rewrite,
standard serial I/O, and parallel I/O.
Table 18.1 lists the Flash Memory Performance (refer to Table 1.1 Functions and Specifications for R8C/1A
Group and Table 1.2 Functions and Specifications for R8C/1B Group for items not listed in Table 18.1).
Table 18.1 Flash Memory Performance
Item
Flash memory operating mode
Division of erase block
Programming method
Erase method
Programming and erasure
control method
Rewrite control method
Number of commands
Programming Blocks 0 and 1
and erasure (program ROM)
(1)
Blocks A and B
endurance
(data flash)
ID code check function
ROM code protect
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 block A, a 1-Kbyte block, and then the block is erased, the erase
count stands at one. When performing 100 or more rewrites, the actual erase count 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 erase count of each
block and limit the number of erase operations to a certain number.
2. Blocks A and B are implemented only in the R8C/1B Group.
Rev.1.30 Dec 08, 2006
REJ09B0252-0130
3 modes (CPU rewrite, standard serial I/O, and parallel I/O mode)
Refer to Figure 18.1 and Figure 18.2
Byte unit
Block erase
Program and erase control by software command
Rewrite control for blocks 0 and 1 by FMR02 bit in FMR0 register.
Rewrite control for block 0 by FMR15 bit and block 1 by FMR16 bit in
FMR1 register.
5 commands
R8C/1A Group: 100 times; R8C/1B Group: 1,000 times
10,000 times
(2)
Standard serial I/O mode supported
Parallel I/O mode supported
Page 245 of 315
Specification
18. Flash Memory