
R8C/14 Group, R8C/15 Group 20. Precautions
Rev.2.10 Jan 19, 2006 Page 245 of 253
REJ09B0164-0210
20.8 Flash Memory Version
20.8.1 CPU Rewrite Mode
20.8.1.1 Operating Speed
Before entering CPU rewrite mode (EW0 mode), select 5MHz or below for the CPU clock using the
CM06 bit in the CM0 register and the CM16 to CM17 bits in the CM1 register. This usage note is not
needed for EW1 mode.
20.8.1.2 Instructions Inhibited Against Use
The following instructions cannot be used in EW0 mode because the flash memory internal data is
referenced: UND, INTO, and BRK instructions.
20.8.1.3 Interrupts
Table 20.1 lists the Interrupt in EW0 Mode and Table 20.2 lists the Interrupt in EW1 Mode.
NOTES:
1. Do not use the address match interrupt while the command is executed because the vector of the
address match interrupt is allocated on ROM.
2. Do not use the non-maskable interrupt while Block 0 is automatically erased because the fixed
vector is allocated Block 0.
Table 20.1 Interrupt in EW0 Mode
Mode Status
When maskable
interrupt request is
acknowledged
When watchdog timer, oscillation stop detection and
voltage monitor 2 interrupt request are acknowledged
EW0 During automatic
erasing
Any interrupt can be
used by allocating a
vector to RAM
Once an interrupt request is acknowledged, the auto-
programming or auto-erasing is forcibly stopped
immediately and resets the flash memory. An interrupt
process starts after the fixed period and the flash
memory restarts. Since the block during the auto-erasing
or the address during the auto-programming is forcibly
stopped, the normal value may not be read. Execute the
auto-erasing again and ensure the auto-erasing is
completed normally.
Since the watchdog timer does not stop during the
command operation, the interrupt request may be
generated. Reset the watchdog timer regularly.
Automatic writing
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