Handling Of Pins On Board; Vpp Pin - NEC 78K0 User Manual

23.5

Handling of Pins on Board

To write the flash memory on-board, connectors that connect the dedicated flash programmer must be provided on
the target system. First provide a function that selects the normal operation mode or flash memory programming
mode on the board.
When the flash memory programming mode is set, all the pins not used for programming the flash memory are in
the same status as immediately after reset. Therefore, if the external device does not recognize the state immediately
after reset, the pins must be handled as described below.
23.5.1 V pin
PP
In the normal operation mode, connect the V
to the V pin in the flash memory programming mode. Perform the following pin handling.
PP
(1) Connect pull-down resistor R
(2) Switch the input of the V
388
CHAPTER 23
pin to V
PP
= 10 kΩ to the V
VPP PP
pin to the programmer side by using a jumper on the board or to GND directly.
PP
Figure 23-13. Example of Connection of V
µ
PD78F0114
Dedicated flash programmer connection pin
V
PP
Pull-down resistor (R
User's Manual U16227EJ2V0UD
µ
PD78F0114
. In addition, a write voltage of 10.0 V (TYP.) is supplied
SS
pin.
Pin
PP
)
VPP