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i2c 通信 问题 总是在while(I2caRegs.I2CSTR.bit.XRDY == 0) 一直卡主

我打算使用TI F28335开发板读取一个湿度传感器的数据,通过I2C 通信。 我附上修改后的程序(基于TI官方的给F28335写的I2C的一个例子程序),发现这个例子程序并不可以运行。每次都是卡在 while(I2caRegs.I2CSTR.bit.XRDY == 0); // wait until first byte is out 这条语句无线循环,并不能继续执行下去。这个问题困扰我很久,是因为这个例子程序本身就有问题吗?还是因为其他原因? 这个传感器我目前使用的datasheet的PDF文件链接如下:https://www.pololu.com/file/0J721/HTU21D(F).pdf 方便您参考。 通信中使用的register还有地址我都严格按照datasheet上面所说应该都没有问题,build这个程序过程中也并没有报错,所以完全不知道我这个程序问题出在哪里。 传感器我使用的是adafruit家已经做好的breakout board,应该已经包括pull up resistor。 这个硬件链接在这里:https://learn.adafruit.com/adafruit-htu21d-f-temperature-humidity-sensor/overview

//
//      Lab12_2: TMS320F28335
//      (C) Frank Bormann
//
//###########################################################################
//
// FILE:	Lab12_2.c
//
// TITLE:	DSP28335 I2C test
//          Temperature Sensor TMP100 connected to GPIO33 (SCL) and GPIO32(SDA)
//			LED GPIO34 as life indicator 100 ms toggle
//			12 bit mode of TMP100, 1/16 degree celcius resolution
//			use watch window for variable "temperature" (type int; qvalue:8)
//###########################################################################
//
//  Ver | dd mmm yyyy | Who  | Description of changes
// =====|=============|======|===============================================
//  3.0 | 24 Jul 2009 | F.B. | Lab12_1  F28335; Header-files Version 1.20 
//  3.1 | 15 Nov 2009 | F.B  | Lab12_1 for F28335 @30MHz and PE revision 5
//###########################################################################
#include "DSP2833x_Device.h"

#define SLAVE_Address 			0x40	


#define SLAVE_Write      0x80
#define SLAVE_READ       0x81
#define SLAVE_Write_humidity      0xE5

// external function prototypes
extern void InitSysCtrl(void);
extern void InitPieCtrl(void);
extern void InitPieVectTable(void);
extern void InitCpuTimers(void);
extern void ConfigCpuTimer(struct CPUTIMER_VARS *, float, float);


// Prototype statements for functions found within this file.
void Gpio_select(void);
void I2CA_Init(void);
interrupt void cpu_timer0_isr(void);

int Value_Read;

//###########################################################################
//						main code									
//###########################################################################
void main(void)
{
	InitSysCtrl();		// Basic Core Init from DSP2833x_SysCtrl.c

	EALLOW;
   	SysCtrlRegs.WDCR= 0x00AF;	// Re-enable the watchdog 
   	EDIS;			// 0x00AF  to NOT disable the Watchdog, Prescaler = 64

	DINT;			// Disable all interrupts
	
	Gpio_select();	// GPI031-LED2, GPIO34-LED3 as output
					// to 2 LEDs on F28335 control-card

	I2CA_Init(); 	//	Initialize I2C device slave address is issued in I2CA_Init() 0x29

	// step 1 : do the configuration:
	//----------------------------------------------------//
	// Send START, set pointer to Configuration register and set resolution to 12 bit
	//hence it is master-transmitter mode to write register to the sensor

	//step 1.1 set integration time to address 0x01+0xFF (2.4ms)

	//step 1.2 set gain to address 0x0F + 0x00 (1*gain)

	//step 1.3 Enable Device to address 0x00+0x03


	I2caRegs.I2CCNT = 2;	// means the DXR includes 2 byte including POINTER_CONFIGURATION and 0x60 for data bit setting
	I2caRegs.I2CDXR = SLAVE_Write;// address for writing

	I2caRegs.I2CMDR.all = 0x6E20; //0x6E20 convert to binary is 0110111000100000
	/*
        Bit15 = 0;	no NACK in receiver mode
		Bit14 = 1;  FREE on emulation halt
		Bit13 = 1;  STT  generate START 
		Bit12 = 0;	reserved
		Bit11 = 1;  STP  generate STOP
		Bit10 = 1;  MST  master mode
		Bit9  = 1;  TRX  ****master - transmitter mode****
		Bit8  = 0;	XA   7 bit address mode
		Bit7  = 0;  RM   nonrepeat mode, I2CCNT determines # of bytes
		Bit6  = 1;  DLB  no loopback mode.it should be '0', from slide 12-12 corrected by Alex.J. 
		Bit5  = 1;  IRS  I2C module enabled
		Bit4  = 0;  STB  no start byte mode
		Bit3  = 0;  FDF  no free data format
		Bit2-0: 0;  BC  **** 8 bit per data byte****
	*/
	while(I2caRegs.I2CSTR.bit.XRDY == 0);		// wait until first byte is out

	I2caRegs.I2CDXR = SLAVE_Write_humidity ;   /*0xE5 read humidity       */

	while(I2caRegs.I2CSTR.bit.SCD == 0);			// wait for STOP condition
		
	I2caRegs.I2CSTR.bit.SCD = 1; //clear stop condition flag

	InitPieCtrl();		// basic setup of PIE table; from DSP2833x_PieCtrl.c
	InitPieVectTable();	// default ISR's in PIE

	EALLOW;
	PieVectTable.TINT0 = &cpu_timer0_isr;
	EDIS;

	InitCpuTimers();	// basic setup CPU Timer0, 1 and 2
	ConfigCpuTimer(&CpuTimer0,150,100000);

	PieCtrlRegs.PIEIER1.bit.INTx7 = 1;

	IER |=1;

	EINT;
	ERTM;

	CpuTimer0Regs.TCR.bit.TSS = 0;	// start timer0

	//step 2 : start read the sensor data including 1 byte pointer register==>2 byte sensor data (upper 8bit) + (lower 8bit)
	while(1)
	{    

		    while(CpuTimer0.InterruptCount == 0);

		    CpuTimer0.InterruptCount = 0;

			EALLOW;
			SysCtrlRegs.WDKEY = 0x55;	// service WD #1
			EDIS;

			//	Send START and set pointer to temperature - register
			I2caRegs.I2CCNT 	= 1;				// pointer to temperature register, count 1 bit only
			I2caRegs.I2CDXR		= SLAVE_READ;// address for reading

			// Send start as master transmitter
	 		I2caRegs.I2CMDR.all = 0x6620; //only change stop to '0', do not generate stop. all others are the same as 6E20
			/*	Bit15 = 0;	no NACK in receiver mode
				Bit14 = 1;  FREE on emulation halt
				Bit13 = 1;  STT  generate START 
				Bit12 = 0;	reserved
				Bit11 = 0;  STP  not generate STOP
				Bit10 = 1;  MST  master mode
				Bit9  = 1;  TRX  master - transmitter mode
				Bit8  = 0;	XA   7 bit address mode
				Bit7  = 0;  RM   nonrepeat mode, I2CCNT determines # of bytes
				Bit6  = 1;  DLB  no loopback mode ,it should be '0', corrected by alex.J
				Bit5  = 1;  IRS  I2C module enabled
				Bit4  = 0;  STB  no start byte mode
				Bit3  = 0;  FDF  no free data format
				Bit2-0: 0;  BC   8 bit per data byte,000	*/
			while(I2caRegs.I2CSTR.bit.ARDY == 0);			// 0=previous cycle has not completed, wait for access ready condition

			I2caRegs.I2CCNT		= 1;	// read 2 byte temperature
			I2caRegs.I2CMDR.all = 0x6C20; //only change bit9 to 0, means master-receiver mode
			/*	Bit15 = 0;	no NACK in receiver mode
				Bit14 = 1;  FREE on emulation halt
				Bit13 = 1;  STT  generate START 
				Bit12 = 0;	reserved
				Bit11 = 1;  STP  generate STOP
				Bit10 = 1;  MST  master mode
				Bit9  = 0;  TRX  master - receiver mode
				Bit8  = 0;	XA   7 bit address mode
				Bit7  = 0;  RM   nonrepeat mode, I2CCNT determines # of bytes
				Bit6  = 0;  DLB  no loopback mode
				Bit5  = 1;  IRS  I2C module enabled
				Bit4  = 0;  STB  no start byte mode
				Bit3  = 0;  FDF  no free data format
				Bit2-0: 0;  BC   8 bit per data byte	*/

			while(I2caRegs.I2CSTR.bit.RRDY == 0);	//0 means receive data NOT available in 12CDRR, wait for 1st byte
			Value_Read = I2caRegs.I2CDRR; // read  8 Bit (integers)
			// RRDY is automatically cleared by read of I2CDRR 

	  		GpioDataRegs.GPBTOGGLE.bit.GPIO34 = 1;		// toggle red LED LD3 @ 28335CC
	  		GpioDataRegs.GPATOGGLE.bit.GPIO31 = 1;
	}
} 

void Gpio_select(void)
{
	EALLOW;
	GpioCtrlRegs.GPAMUX1.all = 0;			// GPIO15 ... GPIO0 = General Puropse I/O
	GpioCtrlRegs.GPAMUX2.all = 0;			// GPIO31 ... GPIO16 = General Purpose I/O
	
	GpioCtrlRegs.GPBMUX1.all = 0;			// GPIO47 ... GPIO32 = General Purpose I/O
	GpioCtrlRegs.GPBMUX1.bit.GPIO32 = 1;	// GPIO32 = I2C - SDA
	GpioCtrlRegs.GPBMUX1.bit.GPIO33 = 1;	// GPIO33 = I2C - SCL

	GpioCtrlRegs.GPBPUD.bit.GPIO32 = 0;    // Enable pull-up for GPIO32 (SDAA)
	GpioCtrlRegs.GPBPUD.bit.GPIO33 = 0;	   // Enable pull-up for GPIO33 (SCLA)

	GpioCtrlRegs.GPBQSEL1.bit.GPIO32 = 3;  // Asynch input GPIO32 (SDAA)
    GpioCtrlRegs.GPBQSEL1.bit.GPIO33 = 3;  // Asynch input GPIO33 (SCLA)

	GpioCtrlRegs.GPBMUX2.all = 0;			// GPIO63 ... GPIO48 = General Purpose I/O

	GpioCtrlRegs.GPCMUX1.all = 0;			// GPIO79 ... GPIO64 = General Purpose I/O
	GpioCtrlRegs.GPCMUX2.all = 0;			// GPIO87 ... GPIO80 = General Purpose I/O
	 

	GpioCtrlRegs.GPADIR.all = 0;			// GPIO0 to 31 as inputs
//	GpioCtrlRegs.GPADIR.bit.GPIO9 = 1;		// GPIO9 = LED LD1
	GpioCtrlRegs.GPADIR.bit.GPIO31 = 1;		// GpIO11 = LED LD2

	GpioCtrlRegs.GPBDIR.all = 0;			// GPIO63-32 as inputs
	GpioCtrlRegs.GPBDIR.bit.GPIO34 = 1;		// peripheral explorer: LED LD3 at GPIO34
	//GpioCtrlRegs.GPBDIR.bit.GPIO49 = 1; 	// peripheral explorer: LED LD4 at GPIO49

	GpioCtrlRegs.GPCDIR.all = 0;			// GPIO87-64 as inputs
	EDIS;
}  

void I2CA_Init(void)
{
	
	I2caRegs.I2CMDR.bit.IRS = 0;	// Reset the I2C module
	// I2C slave address register
	I2caRegs.I2CSAR = SLAVE_Address;
	// I2C Prescale Register
	I2caRegs.I2CPSC.all = 14;		// Internal I2C module clock = SYSCLK/(PSC +1)
								    // = 10 MHz
								    
    I2caRegs.I2CCLKL = 95;			// Tmaster = (PSC +1)[ICCL + 5 + ICCH + 5] / 150MHz
	I2caRegs.I2CCLKH = 95;			// Tmaster =  10 [ICCL + ICCH + 10] / 150 MHz
									// d = 5  for IPSC >1
									
									// for I2C 50 kHz:
									// Tmaster = 20 µs *150 MHz / 10 = 200 = (ICCL + ICCH +10)  
									// ICCL + ICCH = 190
									// ICCL = ICH = 190/2 = 95	

//	I2caRegs.I2CCLKL = 45;
//	I2caRegs.I2CCLKH = 45;			// for I2C 100 kHz:
									// Tmaster = 10 µs *150 MHz / 10 = 100 = (ICCL + ICCH + 10)  
									// ICCL + ICCH = 90
									// ICCL = ICH = 90/2 = 45 	

	I2caRegs.I2CMDR.bit.IRS = 1;	// Take I2C out of reset
}

interrupt void cpu_timer0_isr(void)
{
	CpuTimer0.InterruptCount++;
	EALLOW;
	SysCtrlRegs.WDKEY = 0xAA;	// service WD #2
	EDIS;
	PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;
}
//===========================================================================
// End of SourceCode.
//===========================================================================