EM78P451 datasheet(21/54 Pages) EMC

21 / 54 page

EM78P451

8-Bit Microcontroller with OTP ROM

Product Specification (V1.1) 06.30.2003

• 17

(This specification is subject to change without further notice)

4.5 SERIAL PERIPHERAL INTERFACE MODE

4.5.1 Overview & Features

4.5.1.1 Overview

Figures 8, 9, and 10 show how EM78P451 communicates with other devices through

SPI module. If EM78P451 is a master controller, it sends clock through the SCK pin. A

couple of 8-bit data are transmitted and received at the same time. However, if

EM78P451is defined as a slave, its SCK pin could be programmed as an input pin.

Data will continue to be shifted based on both the clock rate and the selected edge.

4.5.1.2 Features

Operation in either Master mode or Slave mode,

Three-wire or four-wire synchronous communication; that is, full duplex

Programmable baud rates of communication,

Programming clock polarity, (RD bit7)

Interrupt flag available for the read buffer full,

Up to 8 MHz ( maximum ) bit frequency,

SPI Module

SCK

SPIR Reg

SDI

SPIW

Reg

SPIS Reg

/SS

Slave Device

SDO

Bit 7

SPI Module

SPIR Reg

SPIW Reg

SPIS Reg

Master Device

Fig. 8 SPI Master/Slave Communication

EM78P451 Datasheet(PDF) 21 Page - ELAN Microelectronics Corp