Electronics America Single-Chip Microcontrollers User's Manual

CHAPTER 19 FLASH MEMORY VERSION

324 User’s Manual U15331EJ4V1UD

19.1.3 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.

PP pin>

In normal operation mode, input 0 V to the V

PP pin. In flash memory programming mode, a write voltage of 10.0 V

(TYP.) is supplied to the V

PP pin, so perform either of the following.

(1) Connect a pull-down resistor (RV

PP = 10 kΩ) to the VPP pin.

(2) Use the jumper on the board to switch the V

PP pin input to either the programmer or directly to GND.

A V

PP pin connection example is shown below.

Figure 19-4. VPP Pin Connection Example

PD78F9488,

PD78F9489

Connection pin of dedicated flash programmer

Pull-down resistor (RV

)

The following shows the pins used by the serial interface.

Serial Interface Pins Used

3-wire serial I/O SI20, SO20, SCK20

3-wire serial I/O with handshake SI20, SO20, SCK20, P11 (HS)

UART RxD20, TxD20

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.