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I2C COMMUNICATION BETWEEN ST7 AND M24Cxx EEPROM

2 ST7 / M24CXX I2C COMMUNICATION APPLICATION

2.1 HARDWARE CONFIGURATION

The ST7 / M24Cxx I2C communication application hardware consists of a ST72264 microcon-

troller which communicates with an external M24C08 EEPROM through an I2C bus interface.

Figure 1. ST7 / EEPROM I2C Communications Application

2.2 ST7 I2C PERIPHERAL BASIC DRIVERS

In this chapter all registers refer to the ST7 I2C peripheral (unless otherwise specified).

2.3 INITIALIZE THE I2C PERIPHERAL

In this application the initialization of the ST7 I2C peripheral is done completely by software

without taking into account the hardware reset status.

First the Control Register (CR) is cleared and the Data (DR) and Status (SR1,SR2) registers

are touched to clear any pending events.

Then, the peripheral is enabled through the Control Register (CR). This action needs to write

twice in the register due to the fact that the Control Register (CR) bits can be set only when the

PE enable bit is already set. To allow the peripheral to acknowledge the received data the

ACK bit of the Control Register (CR) is set.

As the ST24C08 EEPROM is specified with a maximum I2C clock speed at 100KHz, the ST7

I2C peripheral is set to this speed (CCR=26h) in the application.

ST72264

I2C

VDD

VSS

SCL

2x100

Ω

SDA

2x27K

Ω

M24C08

SCL

SDA

Address=A0h

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