Nec switch User Manual download pdf (Page 195)

CHAPTER 14

µµ

PD78F9801

User’s Manual U12978EJ3V0UD

195

14.1.3 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.

<VPP

pin>

In normal operation mode, input 0 V to the V

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

(TYP.) is supplied to the V

pin, so perform either of the following.

(1) Connect a pull-down resistor (RV

= 10 kΩ) to the V

pin.

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

pin input to either the writer or directly to GND.

A V

pin connection example is shown below.

Figure 14-4. V

PP Pin Connection Example

PD78F9801

Connection pin of dedicated flash programmer

Pull-down resistor (RV

PP)

The following shows the pins used by the serial interface.

Serial Interface Pins Used

3-wire serial I/O SI10, SO10, SCK10

Pseudo-3-wire P12, P11, P10

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.

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Nec switch User Manual Page 195