NEC UPD789426 Series User Manual page 300

<RESET pin>
When the reset signal of the dedicated flash programmer is connected to the RESET signal connected to the
reset signal generator on the board, a signal conflict occurs. To prevent this signal conflict, isolate the connection
with the reset signal generator.
If a reset signal is input from the user system in the flash memory programming mode, a normal programming
operation will not be performed. Do not input signals other than reset signals from the dedicated flash programmer
during this period.
µ
PD78F9436,
78F9456
RESET
<Port pins>
Shifting to the flash memory programming mode sets all the pins except those used for flash memory
programming communication to the status immediately after reset.
Therefore, if the external device does not acknowledge an initial status such as the output high impedance
status, connect the external device to V
<Oscillation pins>
When using an on-board clock, connection of X1, X2, XT1, and XT2 must conform to the methods in the normal
operation mode.
When using the clock output of the flash programmer, directly connect it to the X1 pin with the on-board
oscillator disconnected, and leave the X2 pin open. The subsystem clock conforms to the normal operation mode.
<Power supply>
To use the power output of the flash programmer, connect the V
programmer, respectively.
To use the on-board power supply, connection must conform to that in the normal operation mode. However,
because the voltage is monitored by the flash programmer, therefore, V
connected.
Supply the same power as in the normal operation mode to the other power pins (AV
<Other pins>
Process the other pins (S0 to S14, COM0 to COM3, V
the normal operation mode.
µ
CHAPTER 17 PD78F9436, 78F9456
Figure 17-7. Signal Conflict (RESET Pin)
Signal conflict
Reset signal generator
In the flash memory programming mode, the signal output
by the reset signal generator and the signal output by the
dedicated flash writer conflict, therefore, isolate the
signal on the reset signal generator side
or V via a resistor.
DD SS
LC0
User's Manual U15075EJ2V1UD
Connection pin of dedicated
flash writer
Output pin
and V pins to V
DD SS
of the flash programmer must be
DD
to V , CAPH, and CAPL) in the same manner as in
LC2
and GND of the flash
DD
and AV ).
DD SS
301