4/7

I2C COMMUNICATION BETWEEN ST7 AND M24Cxx EEPROM

lected slave address has to be sent, both by the master.

(CR) followed by writing the slave address in the Data Register (DR) with the least significant

bit correctly set (0 = transmission, 1 = reception).

byte previously transmitted has to be completed correctly. This previous byte transmission

check is done by a polling loop on the BTF flag of the Status Register 1 (SR1). If during this

loop an error is detected in the Status Registers (SR1,SR2) then the application goes into an

infinite loop (no error management).

When the previous data transmission is over, the application writes the new data byte to be

transmitted in the Data Register (DR).

Note: If the data byte to be transmitted is the first one after the slave address, a dummy write

in the Control Register (CR) has to be performed to allow the setting of the BTF bit (see ST7

datasheet for more details). In this application, this dummy write is done by setting the PE bit

for each data byte transmission (see description of EV6 in the Transfer Sequencing diagram

has to be completed correctly. This byte reception check is done by a polling loop on the BTF

flag of the Status Register 1 (SR1). If during this loop an error is detected in the Status Regis-

ters (SR1, SR2) then the application goes in an infinite loop (no error management).

When the data reception is finalized, the application reads the new data byte received in the

Data Register (DR).

To close the communication: Before reading the last byte from the DR register, set the STOP

bit to generate the Stop condition. The interface goes automatically back to slave mode (M/

SL bit cleared). In order to generate the non-acknowledge pulse after the last received data

byte, the ACK bit must be cleared just before reading the second last data byte.

Note: If the data byte to be received is the first one after the slave address, a dummy write in

the Control Register (CR) has to be performed to allow the setting of the BTF bit (see ST7 da-

tasheet for more details). In this application, this dummy write is done by setting the PE bit for

datasheet description).