8. Regarding 12 V application to the V
PP
and MD
2
pins, insure that peak overshoot does not
exceed the maximum rating of 13 V. Also, be sure to connect bypass capacitors to the Vpp
and MD
2
pins*
1
.
Notes: 1. Mode pin input must satisfy the mode programming setup time (t
MDS
) with respect to
the reset release timing. When 12 V is applied to or disconnected from the MD
2
pin, a
delay occurs in the fall and rise waveforms due to the influence of the pull-up/pull-
down resistor connected to the MD
2
pin, etc. For reset release timing, therefore, this
delay must be confirmed with the actual waveform on the board.
2. For notes on applying and cutting V
PP
, refer to 18.10, section (4) of “Programming
and Erasing Flash Memory.”
18.6.2 User Program Mode
When set to user program mode, the H8/3048F can erase and program its flash memory by
executing a user program. On-board updates of the on-chip flash memory can be carried out by
providing on-board circuits for supplying V
PP
and data, and storing an update program in part of
the program area.
To select user program mode, select a mode that enables the on-chip ROM (mode 5, 6, or 7) and
apply 12 V to the V
PP
pin. In this mode, the on-chip peripheral modules operate as they normally
would in mode 5, 6, or 7, except for the flash memory. A watchdog timer overflow, however,
cannot output a reset signal while 12 V is applied to V
PP
. The watchdog timer’s reset output
enable bit (RSTOE) should not be set to 1.
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