AN1810/0305

1/8

Rev. 2.0

AN1810

APPLICATION NOTE

STR71x BSPI COMMUNICATION

WITH M25P10-A SERIAL FLASH

INTRODUCTION

The aim of this application note is to present a practical example of communication using the

BSPI peripheral of the STR71x.

It shows an easy way of communicating between a STR71x microcontroller and a M25P10-A

SPI Serial Flash memory. The purpose is to perform, through BSPI, a write in the memory,

followed by a read of the written data.

The software implemented manages write and read operations between the STR71x BSPI-

interface and the M25P10-A serial flash memory from STMicroelectronics.

1 APPLICATION OVERVIEW

This section summarizes the main features of the connection between STR71x and the SPI

Flash memory.

The Buffered Serial Peripheral Interface (BSPI) allows full-duplex, synchronous, serial com-

munication between devices. A BSPI system may consist of a master and several slaves, or of

a system in which devices may be either master or slave. There is only one master at any time.

During BSPI transfer, data is simultaneously transmitted (shifted out serially) and received

(shifted in serially). Data is transmitted MSB first. The serial clock is used to synchronize the

data transfer during a sequence of eight clock pulses.

The bus signals are:

– The serial clock (SCLK).

– The MOSI (Master Out Slave In).

– The MISO (Master In Slave Out).

Another pin, the SSN pin (slave select), is needed to select Slave or Master Mode for each

device.

In this application note, the STR71x is always used as master (S1.SSN pin = high level). The

STR71x and SPI Flash interface set-up is shown in Figure 2.

1