NEC PD17062 Manuale Utente

µ

The 

µ

PD17062 has two sets of serial interface pins, channel 0 (CH0) and channel 1 (CH1), for exchanging

data with an external unit.

The CH0 pin, which consists of two wires, SDA and SCL, can be operated in any of three modes, clock

synchronous two-wire serial input, clock synchronous two-wire serial output, and two-wire bus

.  The SDA

and SCL pins can be used as general-purpose ports when not being used as a serial interface.

The CH1 pin, which consists of three wires, SCK, SO, and SI, can be operated in any of three modes, clock

synchronous two-wire serial I/O input, clock synchronous two-wire serial I/O output, and three-wire serial I/

O.

CH0 and CH1 cannot be operated at the same time.  Which of pins CH0 and CH1 is used is specified with

the SIO0CH flag (register file:  08H, b

3

) of SMODE (Serial Interface Mode Register).

The two-wire hardware-supported bus mode is for the single master.  Therefore, this mode does not support

any arbitration function.  Arbitration must be done by the software.

Note The two-wire bus mode can be used as an I

2

C bus.

The serial interface mode register specifies the operation mode of the serial interface.  This register sets

up the channel to be used, the protocol, clock, and transmission/reception.

This register is mapped to address 08H in the register file.

All flags of this register are set to 0 at power-on reset.

CH

Pin name

Function

Two-wire bus mode

Serial I/O mode

Port I/O setting register

0

P0A

0

/SDA

Serial data I/O

Serial data I/O

P0ABIO0

P0A

1

/SCL

Shift clock I/O

Shift clock I/O

P0ABIO1

1

P0A

2

/SCK

Cannot be used

Shift clock I/O

P0ABIO2

P0A

3

/SO

Serial data output

P0ABIO3

P0B

0

/SI

Serial data input

P0BBIO0

Bit position

b

3

b

2

b

1

b

0

Flag name

SIO0CH

SB

SIO0MS

SIO0TX