M16C1N Datasheet, PDF (232/238 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/10 SERIES

M16C/1N Group
20. Precautionary Notes in Using the Device
20.9.8 Prohibited Instructions
The following instructions cannot be used in EW0 mode because the CPU tries to read data in
flash memory: UND instruction, INTO instruction, JMPS instruction, JSRS instruction, and BRK
instruction
20.9.9 Interrupt
EW0 Mode
To use interrupts having vectors in a relocatable vector table, the vectors must be relocated to
the RAM area.
• The watchdog timer interrupt is available since the FMR0 and FMR1 registers are forcibly reset
when either interrupt request is generated. Allocate the jump addresses for each interrupt ser-
vice routines to the fixed vector table. Flash memory rewrite operation is aborted when the
watchdog timer interrupt request is generated. Execute the rewrite program again after exiting
the interrupt routine.
• The address match interrupt is not available since the CPU tries to read data in the flash
memory.
EW1 Mode
• Do not acknowledge any interrupts with vectors in the relocatable vector table or address match
interrupt during the auto program or auto erase period.
• Do not use the watchdog timer interrupt.
20.9.10 How to Access
To set the FMR01, FMR02 or FMR11 bit to "1", write "1" after first setting the bit to "0". Do not
generate an interrupt between the instruction to set the bit to "0" and the instruction to set the bit to
"1".
20.9.11 Rewriting in User ROM Area
EW0 Mode
The supply voltage drops while rewriting the block where the rewrite control program is stored,
the flash memory cannot be rewritten because the rewrite control program is not correctly rewrit-
ten. If this error occurs, rewrite the user ROM area while in standard serial I/O mode, parallel I/
O mode, or CAN I/O mode.
EW1 Mode
Avoid rewriting any block in which the rewrite control program is stored.
Rev.1.00 Oct 20, 2004 page 220 of 222
REJ090007-0100Z