R8C/20 Group, R8C/21 Group 19. Flash Memory
Rev.2.00 Aug 27, 2008 Page 406 of 458
REJ09B0250-0200
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.
19.7.1.4 How to Access
Write 0 to the corresponding bits before writing 1 when setting the FMR01, FMR02, or FMR11 bit to 1. Do not
generate an interrupt between writing 0 and 1.
19.7.1.5 Rewriting User ROM Area
In EW0 mode, if the power supply voltage drops while rewriting any block in which the rewrite control
program is stored, the flash memory may not be able to be rewritten because the rewrite control program cannot
be rewritten correctly. In this case, use standard serial I/O mode.
19.7.1.6 Program
Do not write additions to the already programmed address.
Table 19.10 EW1 Mode Interrupts
Mode Status
When Maskable Interrupt
Request is Acknowledged
When Watchdog Timer, Oscillation
Stop Detection and Voltage Monitor 2
Interrupt Request are Acknowledged
EW1 During automatic erasing
(erase- suspend function
is enabled)
The auto-erasing is suspended
after td(SR-SUS) and the
interrupt process is executed.
The auto-erasing can be
restarted by setting the FMR41
bit in the FMR4 register to 0
(erase restart) after the
interrupt process completes.
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 using the erase-suspend
function.
During automatic erasing
(erase- suspend function
is disabled)
The auto-erasing has a priority
and the interrupt request
acknowledgement is waited.
The interrupt process is
executed after the auto-erasing
completes.
During automatic
programming
(program suspend
function enabled)
The auto-programming is
suspended after td(SR-SUS)
and the interrupt process is
executed. The auto-
programming can be restarted
by setting the FMR42 bit in the
FMR4 register to 0 (program
restart) after the interrupt
process completes.
Auto programming
(program suspend
function disabled)
The auto-programming has a
priority and the interrupt
request acknowledgement is
waited. The interrupt process is
executed after the auto-
programming completes.
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