T z / Mbed 2 deprecated I2C_AT24C02

I2C with AT24C02

Dependencies:   mbed

Fork of I2C_on_mbed_AT24cxxx by RedBearLab

main.cpp@3:488563715282, 2017-10-09 (annotated)

Committer:
makeworks
Date:
Mon Oct 09 09:01:14 2017 +0000
Revision:
3:488563715282
Parent:
0:a9d57902bf67 
??24C04????????????

Who changed what in which revision?

UserRevisionLine numberNew contents of line
RedBearLab 0:a9d57902bf67 1
RedBearLab 0:a9d57902bf67 2 #include "mbed.h"
RedBearLab 0:a9d57902bf67 3
makeworks 3:488563715282 4 #define DEV_ADDR 0xA0
makeworks 3:488563715282 5 #define I2C_PageSize 8 /* AT24C02每页有8个字节 */
RedBearLab 0:a9d57902bf67 6
makeworks 3:488563715282 7 I2C i2c(I2C_SDA, I2C_SCL);
RedBearLab 0:a9d57902bf67 8 Serial pc(USBTX, USBRX);
RedBearLab 0:a9d57902bf67 9
RedBearLab 0:a9d57902bf67 10 /**********************************************************************
makeworks 3:488563715282 11 * @brief : Write data to AT24C02
makeworks 3:488563715282 12 *
RedBearLab 0:a9d57902bf67 13 * @param[in] addr : The address of stored
RedBearLab 0:a9d57902bf67 14 * @param[in] *pbuf : The pointer of data
RedBearLab 0:a9d57902bf67 15 * @param[in] length : The length of data
RedBearLab 0:a9d57902bf67 16 *
RedBearLab 0:a9d57902bf67 17 * @return none
makeworks 3:488563715282 18 24C02一页的大小是8，所以写入的时候每到8的倍数的时候要等5ms换页
RedBearLab 0:a9d57902bf67 19 **********************************************************************/
makeworks 3:488563715282 20 void AT24C02_WriteBytes(uint8_t addr, const uint8_t *const pbuf, uint16_t length)
RedBearLab 0:a9d57902bf67 21 {
makeworks 3:488563715282 22 char *_pbuf = (char *)pbuf;
makeworks 3:488563715282 23 uint8_t NumOfFirstPageAvailable = I2C_PageSize - addr % I2C_PageSize;
makeworks 3:488563715282 24 //页是绝对的，按整页大小排列，不是从开始写入的地址开始算。
makeworks 3:488563715282 25 //页写与字节写的区别就是，页写可以一次写多个数据，而字节写只能一次写一个数据。
makeworks 3:488563715282 26 //但由于AT24C02A的一页才8个字节，所以页写也最多写8个数据，而且只能在该页内写，不会发生一次页写同时写两页的情况。
makeworks 3:488563715282 27 if (length <= NumOfFirstPageAvailable)
makeworks 3:488563715282 28 {
makeworks 3:488563715282 29 char buf[length+1];
makeworks 3:488563715282 30 buf[0] = (char)(addr);
makeworks 3:488563715282 31 memcpy(&buf[1], _pbuf, length);
makeworks 3:488563715282 32 i2c.write(DEV_ADDR, buf, length+1, false);
makeworks 3:488563715282 33 wait_ms(5);
makeworks 3:488563715282 34 }
makeworks 3:488563715282 35 else
makeworks 3:488563715282 36 {
makeworks 3:488563715282 37 char buf[NumOfFirstPageAvailable+1];
makeworks 3:488563715282 38 buf[0] = (char)(addr);
makeworks 3:488563715282 39 memcpy(&buf[1], _pbuf, NumOfFirstPageAvailable);
makeworks 3:488563715282 40 i2c.write(DEV_ADDR, buf, NumOfFirstPageAvailable+1, false);
makeworks 3:488563715282 41 wait_ms(5);
makeworks 3:488563715282 42
makeworks 3:488563715282 43 uint16_t NumOfRemainPages = (length - NumOfFirstPageAvailable) / I2C_PageSize;
makeworks 3:488563715282 44 uint8_t NumOfRemainBytes = (length - NumOfFirstPageAvailable) % I2C_PageSize;
makeworks 3:488563715282 45
makeworks 3:488563715282 46 addr += NumOfFirstPageAvailable;//修改寄存器写入地址
makeworks 3:488563715282 47 _pbuf += NumOfFirstPageAvailable;//修改buf地址
makeworks 3:488563715282 48 while (NumOfRemainPages--)//按page写入
makeworks 3:488563715282 49 {
makeworks 3:488563715282 50 //一次可以写入8个字节的数据
makeworks 3:488563715282 51 char buf[I2C_PageSize+1];
makeworks 3:488563715282 52 buf[0] = (char)(addr);
makeworks 3:488563715282 53 memcpy(&buf[1], _pbuf, I2C_PageSize);
makeworks 3:488563715282 54 i2c.write(DEV_ADDR, buf, I2C_PageSize+1, false);
makeworks 3:488563715282 55 wait_ms(5);
makeworks 3:488563715282 56 addr += I2C_PageSize;//修改寄存器写入地址
makeworks 3:488563715282 57 _pbuf += I2C_PageSize;//修改buf地址
makeworks 3:488563715282 58 }
makeworks 3:488563715282 59 if (NumOfRemainBytes != 0)//将剩下的不足一个page的写入
makeworks 3:488563715282 60 {
makeworks 3:488563715282 61 char buf[NumOfRemainBytes+1];
makeworks 3:488563715282 62 buf[0] = (char)(addr);
makeworks 3:488563715282 63 memcpy(&buf[1], _pbuf, NumOfRemainBytes);
makeworks 3:488563715282 64 i2c.write(DEV_ADDR, buf, NumOfRemainBytes+1, false);
makeworks 3:488563715282 65 wait_ms(5);
makeworks 3:488563715282 66 }
makeworks 3:488563715282 67 }
RedBearLab 0:a9d57902bf67 68 }
makeworks 3:488563715282 69
RedBearLab 0:a9d57902bf67 70 /**********************************************************************
makeworks 3:488563715282 71 * @brief : Read data from AT24C02
makeworks 3:488563715282 72 *
makeworks 3:488563715282 73 * @param[in] addr : The address of read in AT24C02
makeworks 3:488563715282 74 * @param[out] *pbuf : The pointer of buffer
RedBearLab 0:a9d57902bf67 75 * @param[in] length : The length of data
RedBearLab 0:a9d57902bf67 76 *
RedBearLab 0:a9d57902bf67 77 * @return none
makeworks 3:488563715282 78 读取数据可以一直读到最后一个地址.序列读没有一页8个字节的限制
makeworks 3:488563715282 79 读没有页的问题，可以从任意地址开始读取任意大小数据，只是超过整个存储器容量时地址才回卷。
RedBearLab 0:a9d57902bf67 80 **********************************************************************/
makeworks 3:488563715282 81 void AT24C02_ReadBytes(uint8_t addr, uint8_t *const pbuf, uint16_t length)
RedBearLab 0:a9d57902bf67 82 {
makeworks 3:488563715282 83 uint8_t *_pbuf = (uint8_t *)pbuf;
makeworks 3:488563715282 84 char buf[1];
makeworks 3:488563715282 85 buf[0] = (char)(addr);
makeworks 3:488563715282 86 i2c.write(DEV_ADDR, buf, 1, false);
makeworks 3:488563715282 87 i2c.read(DEV_ADDR, (char *)_pbuf, length, false);
RedBearLab 0:a9d57902bf67 88 }
RedBearLab 0:a9d57902bf67 89
RedBearLab 0:a9d57902bf67 90
makeworks 3:488563715282 91 uint8_t w_buf[]= "Abcdefghijklmnopqrstuvwxyz1234567890";
makeworks 3:488563715282 92 uint8_t r_buf[100];
RedBearLab 0:a9d57902bf67 93
RedBearLab 0:a9d57902bf67 94
RedBearLab 0:a9d57902bf67 95 int main(void)
RedBearLab 0:a9d57902bf67 96 {
RedBearLab 0:a9d57902bf67 97 uint8_t index;
makeworks 3:488563715282 98 int len = sizeof(w_buf) - 1;
makeworks 3:488563715282 99 pc.printf("len = %d\r\n", len);
RedBearLab 0:a9d57902bf67 100
RedBearLab 0:a9d57902bf67 101 pc.baud(9600);
RedBearLab 0:a9d57902bf67 102 pc.printf("IIC Demo Start \r\n");
makeworks 3:488563715282 103
makeworks 3:488563715282 104 while(1) {
RedBearLab 0:a9d57902bf67 105 wait(2);
makeworks 3:488563715282 106 AT24C02_WriteBytes(0, w_buf, len);
RedBearLab 0:a9d57902bf67 107 wait(0.5);
makeworks 3:488563715282 108 AT24C02_ReadBytes(0, r_buf, len);
makeworks 3:488563715282 109 for(index=0; index<len; index++)
makeworks 3:488563715282 110 pc.printf("%c", r_buf[index]);
makeworks 3:488563715282 111
RedBearLab 0:a9d57902bf67 112 pc.printf("\r\n");
RedBearLab 0:a9d57902bf67 113 }
RedBearLab 0:a9d57902bf67 114 }