On-Board Pin Connections - NEC UPD789426 Series User Manual

17.1.3 On-board pin connections

When programming on the target system, provide a connector on the target system to connect to the dedicated
flash programmer.
There may be cases in which an on-board function that switches from the normal operation mode to flash memory
programming mode is required.
<V pin>
PP
Input 0 V to the V
PP
pin in the flash memory programming mode. Therefore, connect the V
(1) Connect a pull-down resistor of RV
(2) Set the jumper on the board to switch the input of V
The following shows an example of V
µ
<Serial interface pins>
The following shows the pins used by each serial interface.
Note that signal conflict or malfunction of other devices may occur when an on-board serial interface pin that is
connected to another device is connected to the dedicated flash programmer.
CHAPTER 17
pin in the normal operation mode. A writing voltage of 10.0 V (TYP.) is supplied to the V
= 10 kΩ to the V
PP
pin connection.
PP
Figure 17-4 V
PP
PD78F9436,
78F9456
Connection pin of dedicated flash programmer
V
PP
Pull-down resistor (RV
Serial Interface
3-wire serial I/O
UART
User's Manual U15075EJ2V1UD
µ
PD78F9436, 78F9456
pin as follows.
PP
pin.
PP
pin to the programmer side or directly to GND.
PP
Pin Connection Example
)
PP
Pins Used
SI20, SO20, SCK20
RxD20, TxD20
PP
299