AT24C02是一款拥有256bytes(32Page)的EEPROM.
一 ：特点（部分）
1：双线接口；
2：双向数据传输协议；
3：400KHz波特率；
4：硬件写保护；
5：最大5ms写入同步；
6：100万次写操作；
7：100年数据存储。
基本框图
二：绝对参数
三：引脚定义
四：读写操作
AT24C02使用I2C进行读写操作，最大波特率为400KHz。
1：设备地址
设备地址由7bits组成，其中高4位默认为1010b,低三位由A0~A2控制。
2：写操作
1）单字节写
AT24C02单字节写，需要先写入设备地址，之后写入内存地址，最后写入数据。当IIC最后产生STOP模式后，AT24C02将会进入最大5ms的同步时间，此时无法对AT24C02进行操作。
写入时序如下：
2）页写
AT24C02支持按页写操作，每页最大8个字节，一共32页。当进行按页写的时候，AT24C02内存地址会自动增加，如果地址已经是本页的最后地址，但是写操作还未完成，则地址会返回本页起始地址，数据将会覆盖。
3：读操作
AT24C02支持当前地址读取，任意地址读取，连续读取。
1）当前地址读取
AT24C02在上电的时候，每次读写操作，都会自动同步地址。当使用IIC读取数据时，如果在写入设备地址时进行读操作，会读取当前同步地址的值。
2）任意地址读取
AT24C02任意地址读取即为单字节读取。在写完设备地址，内存地址后，进行重起始操作，对数据进行读取。
3）连续读取
AT24C02连续读取时，在读取第一个字节后，IIC不产生STOP条件，则AT24C02会继续传出数据，同时内存地址会自动更新，直到读取到设备的最大地址后，如果继续读取，则会读取设备内存的首地址值。
五：代码参考（IIC 阻塞读写）–.c文件
1 #include "at24c02.h" 2 3 4 #define AT24C02_ADDR (0xA0) 5 6 7 uint8_t at24c02_write_buf[AT24C02_MAX_BYTE_NUM] = {0}; 8 uint8_t at24c02_read_buf[AT24C02_MAX_BYTE_NUM] = {0}; 9 10 11 /** 12 * @brief AT24C02 write data. 13 * @param page, AT24C02 write page. 14 data, Write data buffer. 15 * @retval H_SUCCESS or H_ERROR. 16 */ 17 H_STATUS_T Fn_AT24C02_WriteByte(uint8_t addr, uint8_t data) 18 { 19 uint8_t write_byte[1] = {data}; 20 HAL_StatusTypeDef status = HAL_OK; 21 22 status = HAL_I2C_Mem_Write(&hi2c1, AT24C02_ADDR, addr, I2C_MEMADD_SIZE_8BIT, write_byte, 1, 0xFF); 23 24 if(status != HAL_OK) 25 { 26 return H_ERROR; 27 } 28 29 return H_SUCCESS; 30 } 31 32 33 /** 34 * @brief AT24C02 write page data. 35 * @param page, AT24C02 write page. 36 pData, Write data buffer. 37 len, Write data length. 38 * @retval H_SUCCESS or H_ERROR. 39 */ 40 H_STATUS_T Fn_AT24C02_WritePage(H_AT24C02_PAGE_T page, uint8_t* pData, uint8_t len) 41 { 42 HAL_StatusTypeDef status = HAL_OK; 43 uint8_t page_addr = (uint8_t)page; 44 45 H_PARA_ASSERT((pData == NULL) || (len > AT24C02_PAGE_SIZE)); 46 47 status = HAL_I2C_Mem_Write(&hi2c1, AT24C02_ADDR, page_addr, I2C_MEMADD_SIZE_8BIT, pData, len, 0xFFFF); 48 49 if(status != HAL_OK) 50 { 51 return H_ERROR; 52 } 53 54 return H_SUCCESS; 55 } 56 57 58 /** 59 * @brief AT24C02 write serial data. 60 * @param addr, AT24C02 write data memory. 61 pData, Write data buffer. 62 len, Write data length. 63 * @retval H_SUCCESS or H_ERROR. 64 */ 65 H_STATUS_T Fn_AT24C02_WriteData(uint8_t addr, uint8_t* pData, uint16_t len) 66 { 67 uint8_t start_page_remain = 0; 68 uint8_t remain_page_num = 0; 69 uint8_t write_num = 0; 70 uint32_t i = 0; 71 72 H_PARA_ASSERT(((AT24C02_MAX_BYTE_NUM - (addr + 1)) < len) || (pData == NULL)); 73 74 /* How many memory remain for start page */ 75 start_page_remain = AT24C02_PAGE_SIZE - addr % AT24C02_PAGE_SIZE; 76 77 /* Write first page */ 78 write_num = len > start_page_remain ? start_page_remain : len; 79 for(i = 0; i < write_num; i++) 80 { 81 if(H_SUCCESS != Fn_AT24C02_WriteByte(addr++, *pData++)) 82 { 83 return H_ERROR; 84 } 85 len--; 86 87 /* For auto sync write */ 88 Fn_DelayMs(5); 89 } 90 91 /* Write completely */ 92 if(len == 0) 93 { 94 return H_SUCCESS; 95 } 96 97 /* How many completely page to write */ 98 remain_page_num = len / AT24C02_PAGE_SIZE; 99 100 for(i = 0; i < remain_page_num; i++)101 {102 if(H_SUCCESS != Fn_AT24C02_WritePage((H_AT24C02_PAGE_T)addr, pData, AT24C02_PAGE_SIZE))103 {104 return H_ERROR;105 }106 107 addr += AT24C02_PAGE_SIZE;108 pData += AT24C02_PAGE_SIZE;109 len -= AT24C02_PAGE_SIZE;110 111 /* For auto sync write */112 Fn_DelayMs(5);113 }114 115 /* Write cpm */116 if(len == 0)117 {118 return H_SUCCESS;119 }120 121 /* Last page remain number */122 if(H_SUCCESS != Fn_AT24C02_WritePage((H_AT24C02_PAGE_T)addr, pData, len))123 {124 return H_ERROR;125 }126 127 /* Note: if called Read function after this function, Please insert a delay time between write / read */128 return H_SUCCESS;129 }130 131 132 /**133 * @brief AT24C02 read current address data.134 * @param pData, Read data buffer.135 * @retval H_SUCCESS or H_ERROR.136 */137 H_STATUS_T Fn_AT24C02_ReadCurrentByte(uint8_t *pData)138 {139 H_PARA_ASSERT(pData == NULL);140 141 if(HAL_OK != HAL_I2C_Master_Receive(&hi2c1, AT24C02_ADDR, pData, 1, 0xFF))142 {143 return H_ERROR;144 }145 146 return H_SUCCESS;147 }148 149 150 /**151 * @brief AT24C02 read a byte.152 * @param addr, AT24C02 read data memory.153 pData, Read data buffer.154 * @retval H_SUCCESS or H_ERROR.155 */156 H_STATUS_T Fn_AT24C02_ReadByte(uint8_t addr, uint8_t *pData)157 {158 H_PARA_ASSERT(pData == NULL);159 160 if(HAL_OK != HAL_I2C_Mem_Read(&hi2c1, AT24C02_ADDR, addr, I2C_MEMADD_SIZE_8BIT, pData, 1, 0xFF))161 {162 return H_ERROR;163 }164 165 return H_SUCCESS;166 }167 168 169 /**170 * @brief AT24C02 read serial data.171 * @param addr, AT24C02 read data memory.172 pData, Read data buffer.173 len, Read data length.174 * @retval H_SUCCESS or H_ERROR.175 */176 H_STATUS_T Fn_AT24C02_ReadData(uint8_t addr, uint8_t *pData, uint16_t len)177 {178 H_PARA_ASSERT((pData == NULL) || (len > AT24C02_MAX_BYTE_NUM));179 180 if(HAL_OK != HAL_I2C_Mem_Read(&hi2c1, AT24C02_ADDR, addr, I2C_MEMADD_SIZE_8BIT, pData, len, 0xFFFF))181 {182 return H_ERROR;183 }184 185 return H_SUCCESS;186 }187 188 189 /**190 * @brief AT24C02 clear memory data.191 * @param None.192 * @retval H_SUCCESS or H_ERROR.193 */194 H_STATUS_T Fn_AT24C02_ClearMemData(void)195 {196 uint32_t i = 0;197 uint8_t page_addr = 0x00;198 uint8_t data[AT24C02_PAGE_SIZE] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};199 200 for(i = 0; i < AT24C02_PAGE_NUM; i++)201 {202 if(H_SUCCESS != Fn_AT24C02_WritePage((H_AT24C02_PAGE_T)page_addr, data, AT24C02_PAGE_SIZE))203 {204 return H_ERROR;205 }206 207 page_addr += AT24C02_PAGE_SIZE;208 209 /* For auto sync write */210 Fn_DelayMs(5);211 }212 213 return H_SUCCESS;214 }
六：代码参考：.h文件
1 #ifndef __AT24C02_H__ 2 #define __AT24C02_H__ 3 4 5 #include "iic.h" 6 7 #define AT24C02_BASE_ADDR (0x00) 8 9 #define AT24C02_PAGE_SIZE (0x08) 10 11 #define AT24C02_PAGE_NUM (32) 12 13 #define AT24C02_MAX_BYTE_NUM (256) 14 15 #define AT24C02_MAX_MEM_ADDR (0xFF) 16 17 typedef enum 18 { 19 AT24C02_PAGE0 = AT24C02_BASE_ADDR + 0 * AT24C02_PAGE_SIZE, 20 AT24C02_PAGE1 = AT24C02_BASE_ADDR + 1 * AT24C02_PAGE_SIZE, 21 AT24C02_PAGE2 = AT24C02_BASE_ADDR + 2 * AT24C02_PAGE_SIZE, 22 AT24C02_PAGE3 = AT24C02_BASE_ADDR + 3 * AT24C02_PAGE_SIZE, 23 AT24C02_PAGE4 = AT24C02_BASE_ADDR + 4 * AT24C02_PAGE_SIZE, 24 AT24C02_PAGE5 = AT24C02_BASE_ADDR + 5 * AT24C02_PAGE_SIZE, 25 AT24C02_PAGE6 = AT24C02_BASE_ADDR + 6 * AT24C02_PAGE_SIZE, 26 AT24C02_PAGE7 = AT24C02_BASE_ADDR + 7 * AT24C02_PAGE_SIZE, 27 AT24C02_PAGE8 = AT24C02_BASE_ADDR + 8 * AT24C02_PAGE_SIZE, 28 AT24C02_PAGE9 = AT24C02_BASE_ADDR + 9 * AT24C02_PAGE_SIZE, 29 AT24C02_PAGE10 = AT24C02_BASE_ADDR + 10 * AT24C02_PAGE_SIZE, 30 AT24C02_PAGE11 = AT24C02_BASE_ADDR + 11 * AT24C02_PAGE_SIZE, 31 AT24C02_PAGE12 = AT24C02_BASE_ADDR + 12 * AT24C02_PAGE_SIZE, 32 AT24C02_PAGE13 = AT24C02_BASE_ADDR + 13 * AT24C02_PAGE_SIZE, 33 AT24C02_PAGE14 = AT24C02_BASE_ADDR + 14 * AT24C02_PAGE_SIZE, 34 AT24C02_PAGE15 = AT24C02_BASE_ADDR + 15 * AT24C02_PAGE_SIZE, 35 AT24C02_PAGE16 = AT24C02_BASE_ADDR + 16 * AT24C02_PAGE_SIZE, 36 AT24C02_PAGE17 = AT24C02_BASE_ADDR + 17 * AT24C02_PAGE_SIZE, 37 AT24C02_PAGE18 = AT24C02_BASE_ADDR + 18 * AT24C02_PAGE_SIZE, 38 AT24C02_PAGE19 = AT24C02_BASE_ADDR + 19 * AT24C02_PAGE_SIZE, 39 AT24C02_PAGE20 = AT24C02_BASE_ADDR + 20 * AT24C02_PAGE_SIZE, 40 AT24C02_PAGE21 = AT24C02_BASE_ADDR + 21 * AT24C02_PAGE_SIZE, 41 AT24C02_PAGE22 = AT24C02_BASE_ADDR + 22 * AT24C02_PAGE_SIZE, 42 AT24C02_PAGE23 = AT24C02_BASE_ADDR + 23 * AT24C02_PAGE_SIZE, 43 AT24C02_PAGE24 = AT24C02_BASE_ADDR + 24 * AT24C02_PAGE_SIZE, 44 AT24C02_PAGE25 = AT24C02_BASE_ADDR + 25 * AT24C02_PAGE_SIZE, 45 AT24C02_PAGE26 = AT24C02_BASE_ADDR + 26 * AT24C02_PAGE_SIZE, 46 AT24C02_PAGE27 = AT24C02_BASE_ADDR + 27 * AT24C02_PAGE_SIZE, 47 AT24C02_PAGE28 = AT24C02_BASE_ADDR + 28 * AT24C02_PAGE_SIZE, 48 AT24C02_PAGE29 = AT24C02_BASE_ADDR + 29 * AT24C02_PAGE_SIZE, 49 AT24C02_PAGE30 = AT24C02_BASE_ADDR + 30 * AT24C02_PAGE_SIZE, 50 AT24C02_PAGE31 = AT24C02_BASE_ADDR + 31 * AT24C02_PAGE_SIZE, 51 }H_AT24C02_PAGE_T; 52 53 54 55 /** 56 * @brief AT24C02 write data. 57 * @param page, AT24C02 write page. 58 data, Write data buffer. 59 * @retval H_SUCCESS or H_ERROR. 60 */ 61 H_STATUS_T Fn_AT24C02_WriteByte(uint8_t addr, uint8_t data); 62 63 64 /** 65 * @brief AT24C02 write page data. 66 * @param page, AT24C02 write page. 67 pData, Write data buffer. 68 len, Write data length. 69 * @retval H_SUCCESS or H_ERROR. 70 */ 71 H_STATUS_T Fn_AT24C02_WritePage(H_AT24C02_PAGE_T page, uint8_t* pData, uint8_t len); 72 73 74 /** 75 * @brief AT24C02 write serial data. 76 * @param addr, AT24C02 write data memory. 77 pData, Write data buffer. 78 len, Write data length. 79 * @retval H_SUCCESS or H_ERROR. 80 */ 81 H_STATUS_T Fn_AT24C02_WriteData(uint8_t addr, uint8_t* pData, uint16_t len); 82 83 84 /** 85 * @brief AT24C02 read current address data. 86 * @param pData, Read data buffer. 87 * @retval H_SUCCESS or H_ERROR. 88 */ 89 H_STATUS_T Fn_AT24C02_ReadCurrentByte(uint8_t *pData); 90 91 92 /** 93 * @brief AT24C02 read a byte. 94 * @param addr, AT24C02 read data memory. 95 pData, Read data buffer. 96 * @retval H_SUCCESS or H_ERROR. 97 */ 98 H_STATUS_T Fn_AT24C02_ReadByte(uint8_t addr, uint8_t *pData); 99 100 101 /**102 * @brief AT24C02 read serial data.103 * @param addr, AT24C02 read data memory.104 pData, Read data buffer.105 len, Read data length.106 * @retval H_SUCCESS or H_ERROR.107 */108 H_STATUS_T Fn_AT24C02_ReadData(uint8_t addr, uint8_t *pData, uint16_t len);109 110 111 /**112 * @brief AT24C02 clear memory data.113 * @param None.114 * @retval H_SUCCESS or H_ERROR.115 */116 H_STATUS_T Fn_AT24C02_ClearMemData(void);117 118 119 extern uint8_t at24c02_write_buf[AT24C02_MAX_BYTE_NUM];120 extern uint8_t at24c02_read_buf[AT24C02_MAX_BYTE_NUM];121 122 123 #endif