Diff: main.cpp

Revision:

3:488563715282

Parent:

0:a9d57902bf67

--- a/main.cpp	Thu Jan 07 02:58:22 2016 +0000
+++ b/main.cpp	Mon Oct 09 09:01:14 2017 +0000
@@ -1,88 +1,114 @@
 
 #include "mbed.h"
 
-#define DEV_ADDR    0xA0
+#define DEV_ADDR                0xA0
+#define I2C_PageSize            8            /* AT24C02每页有8个字节 */
 
-I2C     i2c(P0_29, P0_28);
+I2C     i2c(I2C_SDA, I2C_SCL);
 Serial  pc(USBTX, USBRX);
 
 /**********************************************************************
-* @brief            :  Write data to AT24C512
-* 
+* @brief            :  Write data to AT24C02
+*
 * @param[in] addr   : The address of stored
 * @param[in] *pbuf  : The pointer of data
 * @param[in] length : The length of data
 *
 * @return none
+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
 **********************************************************************/
-void AT24C512_WriteBytes(uint16_t addr, uint8_t *pbuf, uint16_t length)
+void AT24C02_WriteBytes(uint8_t addr, const uint8_t *const pbuf, uint16_t length)
 {
-    char buf[length+2];
-    buf[0] = (uint8_t)(addr>>8);
-    buf[1] = (uint8_t)(addr);
-    memcpy(&buf[2], pbuf, length); 
-    i2c.write(DEV_ADDR, buf, length+2, false);
+    char *_pbuf = (char *)pbuf;
+    uint8_t NumOfFirstPageAvailable = I2C_PageSize - addr % I2C_PageSize;
+    //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。
+    //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。
+    //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。
+    if (length <= NumOfFirstPageAvailable)
+    {
+        char buf[length+1];
+        buf[0] = (char)(addr);
+        memcpy(&buf[1], _pbuf, length);
+        i2c.write(DEV_ADDR, buf, length+1, false);
+        wait_ms(5);
+    }
+    else
+    {
+        char buf[NumOfFirstPageAvailable+1];
+        buf[0] = (char)(addr);
+        memcpy(&buf[1], _pbuf, NumOfFirstPageAvailable);
+        i2c.write(DEV_ADDR, buf, NumOfFirstPageAvailable+1, false);
+        wait_ms(5);
+        
+        uint16_t NumOfRemainPages = (length - NumOfFirstPageAvailable) / I2C_PageSize;
+        uint8_t NumOfRemainBytes = (length - NumOfFirstPageAvailable) % I2C_PageSize;
+
+        addr +=  NumOfFirstPageAvailable;//修改寄存器写入地址
+        _pbuf += NumOfFirstPageAvailable;//修改buf地址
+        while (NumOfRemainPages--)//按page写入
+        {
+            //一次可以写入8个字节的数据
+            char buf[I2C_PageSize+1];
+            buf[0] = (char)(addr);
+            memcpy(&buf[1], _pbuf, I2C_PageSize);
+            i2c.write(DEV_ADDR, buf, I2C_PageSize+1, false);
+            wait_ms(5);
+            addr +=  I2C_PageSize;//修改寄存器写入地址
+            _pbuf += I2C_PageSize;//修改buf地址
+        }
+        if (NumOfRemainBytes != 0)//将剩下的不足一个page的写入
+        {
+            char buf[NumOfRemainBytes+1];
+            buf[0] = (char)(addr);
+            memcpy(&buf[1], _pbuf, NumOfRemainBytes);
+            i2c.write(DEV_ADDR, buf, NumOfRemainBytes+1, false);
+            wait_ms(5);
+        }
+    }
 }
+
 /**********************************************************************
-* @brief            :  Read data from AT24C512
-* 
-* @param[in] addr   : The address of read in AT24C512
-* @param[out] *pbuf : The pointer of buffer 
+* @brief            :  Read data from AT24C02
+*
+* @param[in] addr   : The address of read in AT24C02
+* @param[out] *pbuf : The pointer of buffer
 * @param[in] length : The length of data
 *
 * @return none
+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
+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。
 **********************************************************************/
-void AT24C512_ReadBytes(uint16_t addr, uint8_t *pbuf, uint16_t length)
+void AT24C02_ReadBytes(uint8_t addr, uint8_t *const pbuf, uint16_t length)
 {
-    char buf[2];
-    buf[0] = (uint8_t)(addr>>8);
-    buf[1] = (uint8_t)(addr);
-    i2c.write(DEV_ADDR, buf, 2, false);
-    
-    i2c.read(DEV_ADDR, (char *)pbuf, length, false);
+    uint8_t *_pbuf = (uint8_t *)pbuf;
+    char buf[1];
+    buf[0] = (char)(addr);
+    i2c.write(DEV_ADDR, buf, 1, false);
+    i2c.read(DEV_ADDR, (char *)_pbuf, length, false);
 }
 
 
-uint8_t w_buf[11]={'H', 'e', 'l', 'l', 'o', 'W', 'o', 'r', 'l', 'd', '!'};
-uint8_t r_buf[11];
+uint8_t w_buf[]= "Abcdefghijklmnopqrstuvwxyz1234567890";
+uint8_t r_buf[100];
 
 
 int main(void)
 {
     uint8_t index;
+    int len = sizeof(w_buf) - 1;
+    pc.printf("len = %d\r\n", len);
     
     pc.baud(9600);
     pc.printf("IIC Demo Start \r\n");
-    
-    while(1)
-    {
+
+    while(1) {
         wait(2);
-        AT24C512_WriteBytes(0, w_buf, 11);
+        AT24C02_WriteBytes(0, w_buf, len);
         wait(0.5);
-        AT24C512_ReadBytes(0, r_buf, 11);
-        for(index=0; index<11; index++)
-         pc.putc(r_buf[index]);
-         
+        AT24C02_ReadBytes(0, r_buf, len);
+        for(index=0; index<len; index++)
+            pc.printf("%c", r_buf[index]);
+
         pc.printf("\r\n");
     }
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-