M16C28 Datasheet, PDF (316/423 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/Tiny SERIES

M16C/28 Group (M16C/28, M16C/28B)
18. Flash Memory Version
18. Flash Memory Version
18.1 Flash Memory Performance
In the flash memory version, rewrite operation to the flash memory can be performed in three modes : CPU
rewrite mode, standard serial I/O mode and parallel I/O mode.
Table 18.1 lists specifications of the flash memory version. (Refer to Table 1.1 or Table 1.2 for the items
not listed in Table 18.1.
Table 18.1 Flash Memory Version Specifications
Item
Specification
Flash memory operating mode
3 modes (CPU rewrite, standard serial I/O, parallel I/O)
Erase block
See Figures 18.1 to18.4 Flash Memory Block Diagram
Program method
In units of word
Erase method
Block erase
Program, erase control method
Program and erase controlled by software command
Protect method
Number of commands
Block 0 to block 5 are write protected by FMR16 bit.
In addition, the block 0 and block 1 are write protected by bit FMR02
5 commands
Program/Erase
Endurance⁽¹⁾
Data Retentio
Block 0 to 5 (program space) 100 times, 1,000 times (See Tables 1.5 and 1.6 Product Code)
Block A and B (data space) (2) 100 times, 10,000 times (See Tables 1.5 and 1.6 Product Code)
20 years (Topr = 55°C)
ROM code protection
Parallel I/O and standard serial I/O modes are supported
NOTES:
1. Program and erase endurance is defined as number of program-erase cycles per block. If program and erase
endurance is n cycle (n=100, 1000, 10000), each block can be erased and programmed n cycles. For example, if a
2-Kbyte block A is erased after programming one-word data to each address 1,024 times, this counts as one
program and erase endurance. Data cannot be programmed to the same address more than once without erasing
the block. (rewrite prohibited).
2. To reduce the number of program and erase endurance when working with systems requiring numerous rewrites,
write to unused word addresses within the block instead of rewrite. Erase block only after all possible addresses are
used. For example, an 8-word program can be written 128 times maximum before erase becomes necessary.
Maintaining an equal number of times erasure between block A and block B will also improve efficiency. It is
recommended to track the total number of erasure performed per block and to limit the number of erasure.
Rev. 2.00 Jan. 31, 2007 ^{page 296} of 385
REJ09B0047-0200