本帖最后由 Vence 于 2019-9-26 12:51 編輯
以下這篇文章是自己折騰了三天存儲芯片后,并且能夠成功進行字節操作、頁操作的一篇應用型文章,不太想研究原理的可以直接采用本文的代碼和注意事項。
在對24C02或者24C16進行字節、頁讀取、頁存取前,我們需要弄清楚I2C協議、24C02/24C16存儲空間、字節操作和頁操作的時序
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版權聲明:本文為CSDN博主「Pvence」的原創文章,遵循 CC 4.0 BY-SA 版權協議,轉載請附上原文出處鏈接及本聲明。
原文鏈接:https://blog.csdn.net/weixin_40814407/article/details/101228190
I2C協議:I2C是什么協議網上進行百度方可知道,以下只寫使用代碼
- void i2cStart(void) //開始時序
- {
- SDA=1;
- SCL=1;
- _delay(2); //延時2μs
- SDA=0;
- _delay(2);
- SCL=0;
- }
-
- void i2cStop(void) //結束時序
- {
- SDA=0;
- _delay(2);
- SCL=1;
- _delay(2);
- SDA=1;
- }
-
- void i2cAck_MCU(void) //應答時序
- {
- SDA=0;
- _delay(2);
- SCL=1;
- _delay(2);
- SCL=0;
- _delay(2);
- SDA=1;
- _delay(4);
- }
-
-
- void i2cNoAck_MCU(void) //非應答時序
- {
- SDA=1;
- _delay(2);
- SCL=1;
- _delay(2);
- SCL=0;
- _delay(2);
復制代碼 24C02/24C16存儲空間大小24C02就是有2Kbit = 2000/8 = 250個字節,24C16就是有16kbit = 2000個字節,24C02一頁最多可以寫入8個字節,因此可以分成32頁,24C16一頁最多可以寫入16個字節,因此可以分成128頁。
字節寫操作
- void WriteByte_24LC16B(unsigned char input)
- {
- unsigned char bit_count;
- for(bit_count=8;bit_count!=0;bit_count--)
- {
- _delay(2);
- SDA=(_Bool)(input&0x80);
- _delay(2);
- SCL=1;
- _delay(2);
- SCL=0;
- input=input<<1;
- _delay(2);
- }
- SDA=1;
- SDA_CTRL=1; //這里需要看自己使用的芯片設置SDA的IO口為輸入狀態,我用的是HT45F67芯片,SDA端口設置為輸入狀態,用于判斷SDA是否接到主機的應答信號
- _delay(2);
- SCL=1;
- _delay(2);
- if(SDA == 1)
- ack = 0;
- else
- ack = 1;
- SCL=0;
- SDA_CTRL=0; //此處根據自己所使用的芯片將SDA所在的Io口設置為輸出狀態
- }
-
- void Write_24LC16B(unsigned char Wdata,unsigned int RomAddress)
- {
- unsigned char block;
- WriteDeviceAddress=0B10100000;
- block=RomAddress/256;
- RomAddress=RomAddress%256;
- WriteDeviceAddress=WriteDeviceAddress|(block<<1);
- i2cStart();
- WriteByte_24LC16B(WriteDeviceAddress);
- WriteByte_24LC16B((unsigned char)RomAddress);
- WriteByte_24LC16B(Wdata);
- i2cStop();
- _delay(5500);
- }
復制代碼
字節讀操作
- unsigned char ReadByte_24LC16B()
- {
- unsigned char bit_count,rbyte=0;
- SDA=1;
- SDA_CTRL=1;
- _delay(10);
- for(bit_count=8;bit_count!=0;bit_count--)
- {
- rbyte=rbyte<<1;
- _delay(2);
- SCL=1;
- rbyte=rbyte|((unsigned char)(SDA));
- _delay(2);
- SCL=0;
- _delay(2);
- }
- SDA_CTRL=0;
- return(rbyte);
- }
-
-
- unsigned char Read_24LC16B(unsigned int RomAddress)
- {
- unsigned char output,block;
- ReadDeviceAddress=0B10100001;
- WriteDeviceAddress=0B10100000;
- block=RomAddress/256;
- RomAddress=RomAddress%256;
- WriteDeviceAddress=WriteDeviceAddress|(block<<1);
- ReadDeviceAddress=ReadDeviceAddress|(block<<1);
- i2cStart();
- WriteByte_24LC16B(WriteDeviceAddress);
- WriteByte_24LC16B((unsigned char)RomAddress);
- i2cStart();
- WriteByte_24LC16B(ReadDeviceAddress);
- output=ReadByte_24LC16B();
- i2cNoAck_MCU();
- i2cStop();
- _delay(2000);
- return(output);
- }
復制代碼
頁寫操作
- Wdata為輸入數組的首地址,RomAddress為需要進行存儲的地址,范圍在0~2047之間,cnt為一次需要寫入的字節個數,建議采用8的倍數的cnt,因為本函數不采用自動分頁,不是8的倍數會在超出頁寫入最多的字節數之后覆蓋掉原來的數。
- void WritePage_24LC16B(unsigned char *Wdata,unsigned int RomAddress,unsigned char cnt)
- {
- unsigned char block;
- WriteDeviceAddress=0B10100000;
- block=RomAddress/256;
- RomAddress=RomAddress%256;
- WriteDeviceAddress=WriteDeviceAddress|(block<<1);
- i2cStart();
- WriteByte_24LC16B(WriteDeviceAddress);
- WriteByte_24LC16B((unsigned char)RomAddress);
- while(cnt--)
- {
- WriteByte_24LC16B(*Wdata++);
- }
- i2cStop();
- }
-
- 注意:連續進行多頁寫操作,需要在WritePage_24LC16B函數后添加150μs以上的延遲,這段時間,24C02內部需要將數據存儲到芯片內部。
- 例子:
- D_buffer[8] = {1,2,3,4,5,6,7,8};
- WritePage_24LC16B(D_buffer,0,8);
- _delay(150); //延遲150μs以及以上
- WritePage_24LC16B(D_buffer,8,8);
復制代碼
頁讀操作
- void ReadPage_24LC16B(unsigned char *Rdata,unsigned int RomAddress,unsigned char cnt)
- {
- unsigned char block;
- ReadDeviceAddress=0B10100001;
- WriteDeviceAddress=0B10100000;
- block=RomAddress/256;
- RomAddress=RomAddress%256;
- WriteDeviceAddress=WriteDeviceAddress|(block<<1);
- ReadDeviceAddress=ReadDeviceAddress|(block<<1);
- i2cStart();
- WriteByte_24LC16B(WriteDeviceAddress);
- WriteByte_24LC16B((unsigned char)RomAddress);
- i2cStart();
- WriteByte_24LC16B(ReadDeviceAddress);
- while(cnt>1)
- {
- *Rdata++ = ReadByte_24LC16B();
- cnt--;
- i2cAck_MCU(); //發送完讀地址后,需要應答一下
- }
- *Rdata = ReadByte_24LC16B();
- i2cNoAck_MCU(); //讀取最后一個字節需要非應答
- i2cStop();
- _delay(2000);
- }
復制代碼
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