UPD780078 Datasheet, PDF (445/592 Pages) NEC – 8-Bit Single-Chip Microcontrollers

CHAPTER 23 µPD78F0078, 78F0078Y
23.3.3 On-board pin processing
When performing programming on the target system, provide a connector on the target system to connect the
dedicated flash programmer.
An on-board function that allows switching between normal operation mode and flash memory programming mode
may be required in some cases.
<VPP pin>
In normal operation mode, input 0 V to the VPP pin. In flash memory programming mode, a write voltage of 10.0
V (TYP.) is supplied to the VPP pin, so perform the following.
(1) Connect a pull-down resistor (RVPP = 10 kΩ) to the VPP pin.
(2) Use the jumper on the board to switch the VPP pin input to either the programmer or directly to GND.
A VPP pin connection example is shown below.
Figure 23-6. VPP Pin Connection Example
µ PD78F0078, 78F0078Y
VPP
Connection pin of dedicated
flash programmer
Pull-down resistor (RVPP)
<Serial interface pin>
The following shows the pins used by the serial interface.
Serial Interface
3-wire serial I/O (SIO3)
3-wire serial I/O (SIO3)
with handshake
UART (UART0)
I²C bus (IIC0)^Note
Pins Used
SI3, SO3, SCK3
SI3, SO3, SCK3,
P31 (HS)
RXD0, TXD0
SDA0, SCL0
Note µPD78F0078Y only
When connecting the dedicated flash programmer to a serial interface pin that is connected to another device
on-board, signal conflict or abnormal operation of the other device may occur. Care must therefore be taken with
such connections.
User’s Manual U14260EJ3V1UD
445