
R8C/2C Group, R8C/2D Group
20. Flash Memory
Rev.2.00
Dec 05, 2007
REJ09B0339-0200
20. Flash Memory
20.1
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.
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/2D group.
3. To perform programming and erasure, use VCC = 2.7 V to 5.5 V as the supply voltage. Do not perform
programming and erasure at less than 2.7 V.
Table 20.1
Flash Memory Performance
Item
Specification
Flash memory operating mode
3 modes (CPU rewrite, standard serial I/O, and parallel I/O)
Division of erase block
Programming method
Byte unit
Erase method
Block erase
Programming and erasure control method
(3)Program and erase control by software command
Rewrite control method
Rewrite control for blocks 0 to 3 by FMR02 bit in FMR0 register
Rewrite control for block 0 by FMR15 bit and Block 1 by FMR16 bit in
FMR1 register
Number of commands
5 commands
Programming and
erasure
Blocks 0 to 3 (program
ROM)
R8C/2C Group: 100 times; R8C/2D Group: 1,000 times
Blocks A and B (data
10,000 times
ID code check function
Standard serial I/O mode supported
ROM code protect
Parallel I/O mode supported
Table 20.2
Flash Memory Rewrite Modes
Flash memory
Rewrite mode
CPU Rewrite Mode
Standard Serial I/O
Mode
Parallel I/O Mode
Function
User ROM area is rewritten by executing
software commands from the CPU.
EW0 mode: Rewritable in the RAM
EW1 mode: Rewritable in flash memory
User ROM area is
rewritten by a
dedicated serial
programmer.
User ROM area is
rewritten by a
dedicated parallel
programmer.
Areas which can
be rewritten
User ROM area
Operating mode
Single chip mode
Boot mode
Parallel I/O mode
ROM Programmer None
Serial programmer Parallel programmer