EM78P451SWM datasheet(21/54 Pages) EMC

21 / 54 page

EM78P451S

8-Bit Microcontroller with OTP ROM

Product Specification (V1.0) 06.01.2004

• 17

(This specification is subject to change without further notice)

4.5 SERIAL PERIPHERAL INTERFACE MODE

4.5.1 Overview & Features

Overview:

Figures 8, 9, and 10 show how EM78P451S communicates with other devices through

SPI module. If EM78P451S 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

EM78P451S is 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.

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

EM78P451SWM Datasheet(PDF) 21 Page - ELAN Microelectronics Corp