【Artix-7 50T FPGA试用体验】(六)+ “microblaze” 之 IIC驱动BMP180

ti

好久没有发新的帖子了，最近一直都在调试IIC的驱动部分，终于让我调试通过了，下面就来记录一下！！！这次调试花了比较久的时间，中间也遇到了各种坑，最后发现其实大部分都是因为自己对器件的不熟悉导致的。。。话不多说，先上代码!!!

/*
* main.c
*
* Created on: 2016年11月22日
* Author: SEELE
*/
#include
#include
#include "xil_printf.h"
#include "xparameters.h"
#include "xiic.h"
#include "xintc.h"
#include "xil_exception.h"
#include "xenv.h"
#define BMP180_ADDRESS 0x77 /*actual address is 0xEE*/
#define LED_DELAY 500000
const unsigned char OSS = 0; // Oversampling Setting
#define IIC_DEVICE_ID XPAR_IIC_0_DEVICE_ID
#define INTC_DEVICE_ID XPAR_INTC_0_DEVICE_ID
#define INTC_IIC_INTERRUPT_ID XPAR_INTC_0_IIC_0_VEC_ID
XIic Iic;
XIntc InterruptController;
u8 BMPIicAddr;
static int SetupInterruptSystem(XIic *IicPtr);
static void RecvHandler(XIic *InstancePtr);
static void SendHandler(XIic *InstancePtr);
static void StatusHandler(void *CallbackRef, int Status);
volatile int Delay;
s16 ac1;
s16 ac2;
s16 ac3;
u16 ac4;
u16 ac5;
u16 ac6;
s16 b1;
s16 b2;
s16 mb;
s16 mc;
s16 md;
u8 WriteBuffer[10];
u8 Readbuffer[10];
volatile u8 TransmitComplete;
volatile u8 ReceiveComplete;
// b5 is calculated in bmp085GetTemperature(...), this variable is also used in bmp085GetPressure(...)
// so ...Temperature(...) must be called before ...Pressure(...).
long b5;
int IicBMP180_Int()
{
int Status;
XIic_Config *ConfigPtr;
BMPIicAddr = BMP180_ADDRESS;
ConfigPtr = XIic_LookupConfig(IIC_DEVICE_ID);
if (ConfigPtr == NULL) {
return XST_FAILURE;
}
Status = XIic_CfgInitialize(&Iic, ConfigPtr,
ConfigPtr->BaseAddress);
if (Status != XST_SUCCESS) {
return XST_FAILURE;
}
XIic_SetRecvHandler(&Iic,&Iic,
(XIic_Handler) RecvHandler);
XIic_SetStatusHandler(&Iic,&Iic,
(XIic_StatusHandler) StatusHandler);
XIic_SetSendHandler(&Iic,&Iic,
(XIic_Handler) SendHandler);
Status = SetupInterruptSystem(&Iic);
if (Status != XST_SUCCESS){
return XST_FAILURE;
}
Status = XIic_SetAddress(&Iic, XII_ADDR_TO_SEND_TYPE, BMPIicAddr);
if (Status != XST_SUCCESS)
{
return XST_FAILURE;
}
return XST_SUCCESS;
}
static int SetupInterruptSystem(XIic *IicPtr)
{
int Status;
Status = XIntc_Initialize(&InterruptController,INTC_DEVICE_ID);
if (Status != XST_SUCCESS){
return XST_FAILURE;
}
Status = XIntc_Connect(&InterruptController, INTC_IIC_INTERRUPT_ID,
(XInterruptHandler)XIic_InterruptHandler, IicPtr);
if (Status != XST_SUCCESS){
return XST_FAILURE;
}
Status = XIntc_Start(&InterruptController, XIN_REAL_MODE);
if (Status != XST_SUCCESS){
return XST_FAILURE;
}
XIntc_Enable(&InterruptController, INTC_IIC_INTERRUPT_ID);
if (Status != XST_SUCCESS){
return XST_FAILURE;
}
Xil_ExceptionInit();
Xil_ExceptionRegisterHandler(XIL_EXCEPTION_ID_INT,
(Xil_ExceptionHandler)XIntc_InterruptHandler,
&InterruptController);
Xil_ExceptionEnable();
return XST_SUCCESS;
}
int Bmp180WriteData(u16 ByteCount)
{
int Status;
TransmitComplete = 1;
Iic.Stats.TxErrors = 0;
Status = XIic_Start(&Iic);
if (Status != XST_SUCCESS)
{
return XST_FAILURE;
}
Status = XIic_MasterSend(&Iic,WriteBuffer, ByteCount);
if (Status != XST_SUCCESS)
{
return XST_FAILURE;
}
while ((TransmitComplete) || (XIic_IsIicBusy(&Iic) == TRUE)) {
if (Iic.Stats.TxErrors != 0) {
Status = XIic_Start(&Iic);
if (Status != XST_SUCCESS){
return XST_FAILURE;
}
if (!XIic_IsIicBusy(&Iic)){
Status = XIic_MasterSend(&Iic,
WriteBuffer,
ByteCount);
if (Status == XST_SUCCESS){
Iic.Stats.TxErrors = 0;
}
else {
}
}
}
}
Status = XIic_Stop(&Iic);
if (Status != XST_SUCCESS){
return XST_FAILURE;
}
return XST_SUCCESS;
}
int Bmp180ReadData(u8 add,u8 *BufferPtr, u16 ByteCount)
{
int Status;
ReceiveComplete = 1;
WriteBuffer[0] = add;
Status = Bmp180WriteData(0x01);
if (Status != XST_SUCCESS)
{
return XST_FAILURE;
}
Status = XIic_Start(&Iic);
if (Status != XST_SUCCESS){
return XST_FAILURE;
}
Status = XIic_MasterRecv(&Iic, BufferPtr, ByteCount);
if (Status != XST_SUCCESS)
{
return XST_FAILURE;
}
while ((ReceiveComplete) || (XIic_IsIicBusy(&Iic) == TRUE)) {
}
Status = XIic_Stop(&Iic);
if (Status != XST_SUCCESS){
return XST_FAILURE;
}
return XST_SUCCESS;
}
s16 bmp180ReadInt(u8 Address)
{
u8 data[2] = {0,0};
Bmp180ReadData(Address,data,2);
return (s16) data[0]<<8 | data[1];
}
void bmp180Calibration()
{
ac1 = bmp180ReadInt(0xAA);
ac2 = bmp180ReadInt(0xAC);
ac3 = bmp180ReadInt(0xAE);
ac4 = bmp180ReadInt(0xB0);
ac5 = bmp180ReadInt(0xB2);
ac6 = bmp180ReadInt(0xB4);
b1 = bmp180ReadInt(0xB6);
b2 = bmp180ReadInt(0xB8);
mb = bmp180ReadInt(0xBA);
mc = bmp180ReadInt(0xBC);
md = bmp180ReadInt(0xBE);
}
u16 bmp180ReadUT()
{
u16 ut;
//write 0x2e into register 0xf4
WriteBuffer[0] = 0xF4;
WriteBuffer[1] = 0x2E;
Bmp180WriteData(2);
for (Delay = 0; Delay < LED_DELAY; Delay++);
ut = bmp180ReadInt(0xF6);
return ut;
}
float bmp180GetTemperature(u16 ut)
{
long x1, x2;
x1 = (((long)ut - (long)ac6)*(long)ac5)>>15;
x2 = ((long)mc << 11)/(x1 + md);
b5 = x1 + x2;
float temp = ((b5 + 8)>>4);
temp = temp / 10;
return temp;
}
u32 bmp180ReadUP()
{
u8 data[3];
u32 up = 0;
WriteBuffer[0] = 0xF4;
WriteBuffer[1] = (0x34 + (OSS<<6));
Bmp180WriteData(2);
udelay((2 + (3<
for (Delay = 0; Delay < LED_DELAY; Delay++);
u8 add = 0xF6;
Bmp180ReadData(add,data,3);
up = (((unsigned long)data[0]<<16) | ((unsigned long)data[1]<<8) | (unsigned long)data[2]) >> (8-OSS);
return up;
}
s32 bmp180GetPressure(u32 up)
{
long x1, x2, x3, b3, b6, p;
unsigned long b4, b7;
b6 = b5 - 4000;
// Calculate B3
x1 = (b2 * (b6 * b6)>>12)>>11;
x2 = (ac2 * b6)>>11;
x3 = x1 + x2;
b3 = (((((long)ac1)*4 + x3)<>2;
// Calculate B4
x1 = (ac3 * b6)>>13;
x2 = (b1 * ((b6 * b6)>>12))>>16;
x3 = ((x1 + x2) + 2)>>2;
b4 = (ac4 * (unsigned long)(x3 + 32768))>>15;
b7 = ((unsigned long)(up - b3) * (50000>>OSS));
if (b7 < 0x80000000)
p = (b7<<1)/b4;
else
p = (b7/b4)<<1;
x1 = (p>>8) * (p>>8);
x1 = (x1 * 3038)>>16;
x2 = (-7357 * p)>>16;
p += (x1 + x2 + 3791)>>4;
long temp = p;
return temp;
}
float calcAltitude(float pressure)
{
float A = pressure/101325;
float B = 1/5.25588;
float C = pow(A,B);
C = 1 - C;
C = C / 0.0000225577;
return C;
}
int main()
{
float temperature = 0.0;
float pressure = 0.0;
u32 up;
u16 ut;
float atm = 0.0;
float altitude = 0.0;
xil_printf("hello world!nr");
IicBMP180_Int();
bmp180Calibration();
while (1)
{
ut = bmp180ReadUT();
temperature = bmp180GetTemperature(ut);
xil_printf("temp = %drn",(int)temperature);
for (Delay = 0; Delay < LED_DELAY; Delay++);
up = bmp180ReadUP();
pressure = bmp180GetPressure(up);
xil_printf("pressure = %drn",(int)pressure);
for (Delay = 0; Delay < LED_DELAY; Delay++);
}
return 0;
};
/*****************************************************************************/
/**
* This receive handler is called asynchronously from an interrupt context and
* and indicates that data in the specified buffer was received. The byte count
* should equal the byte count of the buffer if all the buffer was filled.
*
* @param CallBackRef is a pointer to the IIC device driver instance which
* the handler is being called for.
* @param ByteCount indicates the number of bytes remaining to be received of
* the requested byte count. A value of zero indicates all requested
* bytes were received.
*
* @return None.
*
* @notes None.
*
****************************************************************************/
static void RecvHandler(XIic *InstancePtr)
{
ReceiveComplete = 0;
}
/*****************************************************************************/
/**
* This status handler is called asynchronously from an interrupt context and
* indicates that the conditions of the IIC bus changed. This handler should
* not be called for the application unless an error occurs.
*
* @param CallBackRef is a pointer to the IIC device driver instance which the
* handler is being called for.
* @param Status contains the status of the IIC bus which changed.
*
* @return None.
*
* @notes None.
*
****************************************************************************/
static void StatusHandler(void *CallbackRef, int Status)
{
}
static void SendHandler(XIic *InstancePtr)
{
TransmitComplete = 0;
}

复制代码

上面这部分是全部代码，下面是运行结果

其中气压值对应的Pa，温度对应的是摄氏度，我查了一下还是很准的。
这款BMP180温度气压模块是一款高精度，小封装的温度气压传感器，可以用来做一下海拔高度的计算。不过这里我仅仅是读取了温度值和气压值。在模块的内部存储了11个校准系数用来计算温度值和气压值。
而且在使用的过程中需要先计算出温度值，才能计算气压值。

上图就是存储在内部的校准参数。在BMP180的手册中详细描述了BMP180的计算流程，如下图所示。

在驱动的过程中也遇到了很多坑，主要是在延迟上面，由于器件要求每次使能采集温度和气压，需要延迟4.5ms。
而我一开始使用udelay()函数进行延时，发送怎么读取温度和气压都不对，而单独读取温度是对的。搞得我以为是IP核的配置有问题，最后发现是udelay()函数根本就没有定义，所以根本没有延时，最后试用了最简单的for(;;)实现了延时功能，结果终于正确了！！！！
附件中提供了，iic软核的datasheet，在开发之前看一下还是有很大帮助的！！！