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Stc8h development (XII): I2C drive AT24C08, at24c32 series EEPROM storage

2022-07-06 03:53:00 【IOsetting】

Catalog

AT24C series

AT24C Series are common EEPROM Memory chips , It is often used to save parameters and data of power failure memory

  • Capacity : The model represents its capacity , from AT24C01 To AT24C1024, Storage capacity is 1K BIT ~ 1024K BIT, Note that the unit is Bit, If converted to bytes, it is 128 byte ~ 128K byte
  • voltage : The whole series has 2.7V (2.7V to 5.5V) and 1.8V (1.8V to 5.5V) Two versions , All compatible 3.3V and 5V
  • encapsulation : 8-lead PDIP, 8-lead JEDEC SOIC, 8-lead MAP, 5-lead SOT23, 8-lead TSSOP and 8-ball dBGA2

Compared with other memory devices

  • Small capacity
  • Mr Abhisit , Almost unlimited erasure times : 10 More than ten thousand times , Typical value is millions
  • Ultra long data retention : 40 In the above
  • Operating temperature range : Industrial grade [-55℃,125℃]
  • I2C Bus , It only needs SCL and SDA Two interfaces , And can be compared with other I2C Device reuse
  • Support write protection

Because of these characteristics , AT24C It is often used in some small capacity but high stability , And the scene that needs to be rewritten repeatedly .

AT24C Device address and storage address

Device address

AT24C The device address of is a byte , In binary 1010 start , adopt A0,A1,A2 These three pin Adjustment . Depending on the capacity , There are differences between device address and addressing range

AT24C01 - AT24C16

The storage address of this series is only one byte , So memory addressing only 256 byte (2048 bit), about AT24C01, AT24C02 It's directly addressable , For larger capacity models , It is necessary to divide the memory address in combination with the device address page visit

  • AT24C01, AT24C02: Device address 0xA0 - 0xAE, The first 8 Is it R/W, The same I2C Can coexist on the bus 8 Similar devices
  • AT24C04: 0xA0 - 0xAC, The first 7 Is it page choice , The first 8 Is it R/W, The same I2C Can coexist on the bus 4 Similar devices
  • AT24C08: 0XA0 - 0xA8, The first 6,7 Is it page choice , The first 8 Is it R/W, The same I2C Can coexist on the bus 2 Similar devices
  • AT24C16: 0XA0, The first 5, 6,7 Is it page choice , The first 8 Is it R/W, The same I2C Only... Can exist on the bus 1 Similar devices

AT24C32, AT24C64

  • Start with this capacity , The storage address becomes two bytes
  • Device address 0xA0 - 0xAE, The first 8 Is it R/W, The same I2C Can coexist on the bus 8 Similar devices

AT24C128, AT24C256, AT24C512

  • Device address 0xA0 - 0xA6, The first 5 The bit is fixed to 0, The first 8 Is it R/W, The same I2C Can coexist on the bus 4 Similar devices
  • Store two bytes of address

AT24C1024

  • Device address 0xA0 - 0xA4, The first 5 The bit is fixed to 0, The first 7 Is it page choice , The first 8 Is it R/W, The same I2C Can coexist on the bus 2 Similar devices
  • Store two bytes of address , So memory addressing only 64K byte , 128K It needs to be divided into two page Visit

adopt STC8H visit AT24C Series memory chips

Be careful

visit AT24C when I2C The frequency of the bus should not be too high .

  • AT24C Series of I2C The maximum bus frequency is 400KHz(2.7V), stay 1.8V The frequency will drop to 100KHz
  • Compatible chips on the market may not meet the previous indicators
  • STC8H The main frequency of the series is basically from 24MHz start , Even run directly in 36.864MHz On
  • STC8H I2C The frequency of the bus is based on FOSC Calculated , In the initial debugging stage , Be sure to set a large prescaler , This can ensure that the problem does not lie in the high frequency

connection

about DIP8 encapsulation , The wiring mode is the same , The test uses STC8H3K64S2, It can be directly replaced by STC8H Other models , Except for the following 4 individual pin, You also need to choose to A0, A1, A2 Pick up GND Or connect VCC

P32   -> SCL
P33   -> SDA
GND   -> GND
3.3V  -> VCC

AT24C08 Access examples

This example demonstrates the access mode of single byte storage address series models 

#include "fw_hal.h"

//  Set the address  0xA0,  Corresponding A0,A1,A2 Three pin All grounded ,  Modify according to your own wiring during the test 
#define AT24C_ADDR 0xA0

__CODE int8_t dat[20] = {
    0xC0,0xC1,0xC2,0xC3,0xC4,0xC5,0xC6,0xC7,0xC8,0xC9,0xCA,0xCB};

// I2C initialization 
void I2C_Init(void)
{
    
    //  Master mode 
    I2C_SetWorkMode(I2C_WorkMode_Master);
    /** * I2C  Bus frequency  = FOSC / 2 / (__prescaler__ * 2 + 4)  Set the maximum value here 0x3F */
    I2C_SetClockPrescaler(0x3F);
    //  choice I2C port 
    I2C_SetPort(I2C_AlterPort_P32_P33);
    //  Enable  I2C
    I2C_SetEnabled(HAL_State_ON);
}

// GPIO initialization 
void GPIO_Init(void)
{
    
    // SDA
    GPIO_P3_SetMode(GPIO_Pin_3, GPIO_Mode_InOut_QBD);
    // SCL
    GPIO_P3_SetMode(GPIO_Pin_2, GPIO_Mode_Output_PP);
}


int main(void)
{
    
    uint8_t offset, i, buf[20];

    SYS_SetClock();
    //  Turn on  UART1, baud 115200 with Timer2, 1T mode, no interrupt
    UART1_Config8bitUart(UART1_BaudSource_Timer2, HAL_State_ON, 115200);

    GPIO_Init();
    I2C_Init();
    //  Address 0x00 Write continuously 12 Bytes 
    I2C_Write(AT24C_ADDR, 0x00, dat, 12);

    while(1)
    {
    
    	//  branch 4 Time ,  The starting address is incremented ,  Read continuously each time 6 Bytes and output through serial port 
        for (offset = 0; offset < 4; offset++)
        {
    
            I2C_Read(AT24C_ADDR, offset, buf, 6);
            for (i = 0; i < 6; i++)
            {
    
                UART1_TxHex(buf[i]);
                UART1_TxChar(':');
            }
            UART1_TxString(" ");
            SYS_Delay(10);
        }
        UART1_TxString("\r\n");
        //  interval 1 second 
        SYS_Delay(1000);
    }
}

Code address

AT24C32 Access examples

This example demonstrates the access mode of double byte storage address series models 

#include "fw_hal.h"

// AT24C device address, change according to the voltage level of A0/A1/A2
#define AT24C_ADDR 0xA0
// Test data
__CODE int8_t dat[20] = {
    0xC0,0xC1,0xC2,0xC3,0xC4,0xC5,0xC6,0xC7,0xC8,0xC9,0xCA,0xCB};

void I2C_Init(void)
{
    
    // Master mode
    I2C_SetWorkMode(I2C_WorkMode_Master);
    /** * I2C clock = FOSC / 2 / (__prescaler__ * 2 + 4) */
    I2C_SetClockPrescaler(0x3F);
    // Switch alternative port
    I2C_SetPort(I2C_AlterPort_P32_P33);
    // Start I2C
    I2C_SetEnabled(HAL_State_ON);
}

void GPIO_Init(void)
{
    
    // SDA
    GPIO_P3_SetMode(GPIO_Pin_3, GPIO_Mode_InOut_QBD);
    // SCL
    GPIO_P3_SetMode(GPIO_Pin_2, GPIO_Mode_Output_PP);
}

int main(void)
{
    
    uint8_t offset, i, buf[20];

    SYS_SetClock();
    // UART1 configuration: baud 115200 with Timer2, 1T mode, no interrupt
    UART1_Config8bitUart(UART1_BaudSource_Timer2, HAL_State_ON, 115200);

    GPIO_Init();
    I2C_Init();
    //  And AT24C08 The difference between the examples is that 16bit Address 
    I2C_Write16BitAddr(AT24C_ADDR, 0x0000, dat, 12);

    while(1)
    {
    
        for (offset = 0; offset < 4; offset++)
        {
    
        	//  And AT24C08 The difference between the examples is that 16bit Address 
            I2C_Read16BitAddr(AT24C_ADDR, 0x0000|offset, buf, 6);
            for (i = 0; i < 6; i++)
            {
    
                UART1_TxHex(buf[i]);
                UART1_TxChar(':');
            }
            UART1_TxString(" ");
            SYS_Delay(10);
        }
        UART1_TxString("\r\n");
        SYS_Delay(1000);
    }
}

Code address

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