M16C6S_09 Datasheet, PDF (198/208 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

M16C/6S Group
Usage Notes
Flash Memory Version
Functions to Inhibit Rewriting Flash Memory Rewrite
ID codes are stored in addresses 0FFFDF16, 0FFFE316, 0FFFEB16, 0FFFEF16, 0FFFF316, 0FFFF716,
and 0FFFFB16. If wrong data are written to theses addresses, the flash memory cannot be read or written
in standard serial I/O mode.
The ROMCP register is mapped in address 0FFFFF16. If wrong data is written to this address, the flash
memory cannot be read or written in parallel I/O mode.
In the flash memory version of MCU, these addresses are allocated to the vector addresses (“H”) of fixed
vectors. The b3 to b0 in address 0FFFFF16 are reserved bits. Set these bits to 11112.
Regarding Programming/Erasure Times and Execution Time
As the number of programming/erasure times increases, so does the execution time for software com-
mands (Program, and Block Erase).
The software commands are aborted by hardware reset 1, brown-out detection reset (hardware reset 2),
and watchdog timer interrupt. If a software command is aborted by such reset or interrupt, the affected
block must be erased before reexecuting the aborted command.
Definition of Programming/Erasure Times
“Number of programs and erasure” refers to the number of erasure per block.
If the number of program and erasure is n (n=100 1,000) each block can be erased n times. For example,
if a 8K byte block A is erased after writing 1 word data 4096 times, each to a different address, this is
counted as one program and erasure. However, data cannot be written to the same adrress more than
once without erasing the block. (Rewrite prohibited)
Boot Mode
An undefined value is sometimes output in the I/O port until the internal power supply becomes stable
when “H” is applied to the CNVSS pin and “L” is applied to the RESET pin.
When setting the CNVSS pin to “H”, the following procedure is required:
(1) Apply an “L” signal to the RESET pin and the CNVSS pin.
(2) Bring VCC to more than 2.7V, and wait at least 2 msec. (Internal power supply stable waiting time)
(3) Apply an “H” signal to the CNVSS pin.
(4) Apply an “H” signal to the RESET pin.
When the CNVSS pin is “H” and RESET pin is “L”, P67 pin is connected to the pull-up resister.
Rev.5.01 Dec 10, 2009 page 198 of 201
REJ03B0014-0501