FT2232 I2C 8位设备地址 8位寄存器地址 8位数据读写示例

最新推荐文章于 2025-05-27 09:09:03 发布

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最新推荐文章于 2025-05-27 09:09:03 发布 · 2.1k 阅读

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这篇博客详细介绍了使用FT2232进行I2C通信的步骤，包括开始信号、发送设备地址、寄存器地址和数据，以及读取响应和停止信号的流程。代码示例展示了如何设置MPSSE接口并控制SCL和SDA线来完成I2C通信。

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参考官方文档：AN_135_MPSSE_Basics.pdf, AN_113_FTDI_Hi_Speed_USB_To_I2C_Example.pdf

有疑问的部分，色标已经标出。具体的执行时序流程，参考上一篇。

// Set initial states of the MPSSE interface
// - low byte, both pin directions and output values
// Pin name Signal Direction Config Initial State Config
// ADBUS0 TCK/SK output 1 high 1 -------------------->SCL(BIT0)
// ADBUS1 TDI/DO output 1 low 1 ---------------------->output SDA(BIT1)
// ADBUS2 TDO/DI input 0 0 ----------------------->input SDA
// ADBUS3 TMS/CS output 0 high 0
// ADBUS4 GPIOL0 output 1 low 0
// ADBUS5 GPIOL1 output 0 low 0
// ADBUS6 GPIOL2 output 0 high 0
// ADBUS7 GPIOL3 output 0 high 0

//---------------------I2C--------------------------------------------------------------------------------------------------
void FT2232I2cByteWrOneTime(unsigned char DeviceAddr,unsigned char RegAddr,unsigned char RegVal)
{
   DWORD dwCount;
   FT_STATUS ftStatus = FT_OK;
   //-------------I2cStart-------------------------
for(dwCount=0; dwCount < 4; dwCount++) // Repeat commands to ensure the minimum period of the stop setup time ie 600ns is achieved
   {

//// Set initial states of the MPSSE interface
       OutputBuffer[dwNumBytesToSend++] = 0x80; //// Configure data bits low-byte of MPSSE port, Command to set directions of lower 8 pins and force value on bits set as output
       OutputBuffer[dwNumBytesToSend++] = 0x03; //// Initial state config above, Set SDA, SCL high, WP disabled by SK, DO at bit „1‟, GPIOL0 at bit „0‟
       OutputBuffer[dwNumBytesToSend++] = 0x13; //// Direction config above, Set SK,DO,GPIOL0 pins as output with bit „1‟, other pins as input with bit „0‟
   }

   for(dwCount=0; dwCount < 20; dwCount++)
   {
       OutputBuffer[dwNumBytesToSend++] = 0x80; //Command to set directions of lower 8 pins and force value on bits set as output
       OutputBuffer[dwNumBytesToSend++] = 0x01; //Set SDA low, SCL high, WP disabled by SK at bit 1, DO, GPIOL0 at bit 0
       OutputBuffer[dwNumBytesToSend++] = 0x13; //Set SK,DO,GPIOL0 pins as output with bit 1, other pins as input with bit 0
   }
   for(dwCount=0; dwCount < 20; dwCount++)
   {
   OutputBuffer[dwNumBytesToSend++] = 0x80; //Command to set directions of lower 8 pins and force value on bits set as output
   OutputBuffer[dwNumBytesToSend++] = 0x00;
   OutputBuffer[dwNumBytesToSend++] = 0x13; //Set SK,DO,GPIOL0 pins as output with bit 1, other pins as input with bit 0
   }

//Sleep(10); //Delay for a while

   //-------------I2cSendByteAndNotCheckACK_DeviceAddr-------------------------

   OutputBuffer[dwNumBytesToSend++] = MSB_FALLING_EDGE_CLOCK_BYTE_OUT; //Clock data byte out on -ve Clock Edge MSB first
   OutputBuffer[dwNumBytesToSend++] = '\x00';
   OutputBuffer[dwNumBytesToSend++] = '\x00'; //Data length of 0x0000 means 1 byte data to clock out(8 bit)
   OutputBuffer[dwNumBytesToSend++] = DeviceAddr;

   //Get slave's ack
   for(dwCount=0; dwCount<4; dwCount++) // Repeat commands to ensure the minimum period of the stop setup time ie 800ns is achieved
   {
       OutputBuffer[dwNumBytesToSend++] = 0x80; //Command to set directions of lower 8 pins and force value on bits set as output
       OutputBuffer[dwNumBytesToSend++] = 0x02;
       OutputBuffer[dwNumBytesToSend++] = 0x13; //Set SK,DO,GPIOL0 pins as output with bit 1, other pins as input with bit 0
   }
   for(dwCount=0; dwCount<10; dwCount++) // Repeat commands to ensure the minimum period of the stop setup time ie 800ns is achieved
   {
       OutputBuffer[dwNumBytesToSend++] = 0x80; //Command to set directions of lower 8 pins and force value on bits set as output
       OutputBuffer[dwNumBytesToSend++] = 0x03;
       OutputBuffer[dwNumBytesToSend++] = 0x13; //Set SK,DO,GPIOL0 pins as output with bit 1, other pins as input with bit 0
   }
   for(dwCount=0; dwCount<40; dwCount++) // Repeat commands to ensure the minimum period of the stop setup time ie 800ns is achieved
   {
       OutputBuffer[dwNumBytesToSend++] = 0x80; //Command to set directions of lower 8 pi