공부/HW

210316 Serial EEPROM CAT24C32 (Byte read)

강경국 2021. 3. 23. 12:42
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Serial EEPROM CAT24C32 (32kbit)

STM32F103을 이용한 I2C Byte read 기능 구현.

 

환경) Compiler : System Workbench, CMSIS library

 

Sequence는 아래를 참조하여 구현한다.

 

 

구현한 코드

 

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int EEPROM_i2c_readByte(uint8_t slaveAddr, uint16_t regAddr, uint8_t * retByte) {
 
    I2C_AcknowledgeConfig(I2C2, ENABLE);
 
    I2C_GenerateSTART(I2C2, ENABLE);
 
    int timeout = I2C_TIMEOUT;
    while(!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_MODE_SELECT)) {
        if((timeout--) == 0) {
            return -1;
        }
        delay_us(1);
    }
 
    I2C_Send7bitAddress(I2C2, slaveAddr, I2C_Direction_Transmitter);
 
    timeout = I2C_TIMEOUT;
    while(!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED)) {
        if((timeout--) == 0) {
            return -2;
        }
        delay_us(1);
    }
 
    // Register Address 15-8
    I2C_SendData(I2C2, (uint8_t)((regAddr >> 8) & 0x00FF));
 
    timeout = I2C_TIMEOUT;
    while(!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_BYTE_TRANSMITTED)) {
        if((timeout--) == 0) {
            return -3;
        }
        delay_us(1);
    }
 
    // Register Address 7-0
    I2C_SendData(I2C2, (uint8_t)(regAddr & 0x00FF));
 
    timeout = I2C_TIMEOUT;
    while(!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_BYTE_TRANSMITTED)) {
        if((timeout--) == 0) {
            return -4;
        }
        delay_us(1);
    }
 
    I2C_GenerateSTART(I2C2, ENABLE);
 
    timeout = I2C_TIMEOUT;
    while(!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_MODE_SELECT)) {
        if((timeout--) == 0) {
            return -5;
        }
        delay_us(1);
    }
 
    I2C_Send7bitAddress(I2C2, slaveAddr, I2C_Direction_Receiver);
 
    timeout = I2C_TIMEOUT;
    while(!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED)) {
        if((timeout--) == 0) {
            return -6;
        }
        delay_us(1);
    }
 
    timeout = I2C_TIMEOUT;
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_BYTE_RECEIVED)) {
        if((timeout--) == 0) {
            return -7;
        }
        delay_us(1);
    }
 
    *retByte = I2C_ReceiveData(I2C2);
 
    I2C_AcknowledgeConfig(I2C2, DISABLE);
 
    I2C_GenerateSTOP(I2C2, ENABLE);
 
    timeout = I2C_TIMEOUT;
    while(I2C_GetFlagStatus(I2C2, I2C_FLAG_BUSY)) {
        if((timeout--) == 0) {
            return -8;
        }
        delay_us(1);
    }
 
    delay_us(100);
 
    return 0;
}
 
 
void delay_us(int us)
{
    volatile u32 i;
 
    for(i = us; i > 0; i--) // 72clock = 1us
    {
        asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop");
        asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop");
        asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop");
        asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop");
        asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop");
        asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop");
        asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop"); asm("nop");
        asm("nop"); asm("nop");
    }
}
 
 
// Use example
uint8_t addr = 0xA0;    // Device address
uint8_t value = 0;
int  targetaddr = 0x00;
EEPROM_i2c_readByte(addr, targetaddr, &value);
 
cs

 

 

 

 

 

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