STC15W reads RM3100 data via SPI

I recently took over a project that required me to read RM3100 data from an STC microcontroller. I checked on Taobao and found that it was not cheap.

This thing itself is not very difficult, the problem is that there is no reference material, just the official website.

The program idea is very simple, adjust SPI communication and adjust initialization settings.

Looking at the data sheet, these registers can all be set, but fortunately, not too many.

There is no need to set them all up, just set the ones you need. I mainly set the continuous measurement and conversion cycle.

/**

 * @brief Sets cycle count and updates gain and max_data_rate values

 * @param[in] desire value PNI recomends values ​​between 30 and 400 Hz

 * @return 1 if successful, 0 otherwise.

 */

void setCycleCount ( u16 value ) 

{

char to_reg[6];

if (value > 400)

value=400;

else if (value < 30)

value=30;

to_reg[0] = value>>8;

to_reg[1] = value;

to_reg[2] = to_reg[0];

to_reg[3] = to_reg[1];

to_reg[4] = to_reg[0];

to_reg[5] = to_reg[1];

SPIWriteBytes(M3D_3100_CCX,6,to_reg);

}

/**

 * @brief Sets data rate in Continuous Measurement Mode.

 * Fails if desire datarate is higher than the max data rate recommended by PNI.

 * @param[in] Data rate configuration BYTE

 * @return 1 if successful, 0 otherwise.

 */

void setCMMdatarate ( char conf ) 

{

char *ptr;

float temp = 1000;

switch (conf){

case CMM_UPDATERATE_600: temp=600;

break;

case CMM_UPDATERATE_300: temp=300;

break;

case CMM_UPDATERATE_150: temp=150;

break;

case CMM_UPDATERATE_75 : temp=75;

break;

case CMM_UPDATERATE_37 : temp=37;

break;

case CMM_UPDATERATE_18 : temp=18;

break;

case CMM_UPDATERATE_9 : temp=9;

break;

case CMM_UPDATERATE_4_5: temp=4.5;

break;

case CMM_UPDATERATE_2_3: temp=2.3;

break;

case CMM_UPDATERATE_1_2: temp=1.2;

break;

case CMM_UPDATERATE_0_6: temp=0.6;

break;

case CMM_UPDATERATE_0_3: temp=0.3;

break;

case CMM_UPDATERATE_0_15: temp=0.15;

break;

case CMM_UPDATERATE_0_075: temp=0.075;

break;

}

ptr = &conf;

SPIWriteBytes(M3D_3100_TMRC,1,ptr);

}

After setting, the data is read

/**********************/

/**** ¶ÁÈ¡ Êý¾Ý ******/

/**********************/

void MagGetData(void) 

{

int i = 0;

unsigned char temp[9]={0};

static long Mag_Data[3]={0};

static char state = 0; //0 :cmd 1:wait get data

static char cNoDataCnt = 0;

if (CheckMagDataReady())

{

//´«¸ÐÆ÷×¼±¸ºÃ´¦ÀíÊý¾Ý

state = 0;

//¶ÁÈ¡ 1. 2. 3. 4. 5. 6. 7. 8. 9.

SPIReadBytes(0xA4,9,temp);

//

Mag_Data[0]=temp[0]<<16 | temp[1]<<8 | temp[2]; //ned×ø±êϵ--Ç°ÌáÊÇËùÓк¸½Ó¶¼ÊDZê¼Çλº¸½Óµ½N

Mag_Data[1]=temp[3]<<16 | temp[4]<<8 | temp[5];

Mag_Data[2]=temp[6]<<16 | temp[7]<<8 | temp[8];

for(i=0;i<3;i++)

{

if(Mag_Data[i]&0x00800000)

Mag_Data[i]|=0xff000000;

}

temp[0]=0x70;

SPIWrite(0,0x70);

}

else

{

//´«¸ÐÆ÷»¹Ã»×¼±¸ºÃ´¦ÀíÊý¾Ý

cNoDataCnt+=5;

if (cNoDataCnt>=20)

{

cNoDataCnt=0;

SPIWrite(0,0x70);

}

}

//Êý¾ÝתÒƵ½½á¹¹Ìå

rm3100.rx = Mag_Data[0];

rm3100.ry = Mag_Data[1];

rm3100.rz = Mag_Data[2];

//´®¿ The most beautiful thing ÈýÖá²ÎÊý

printf("´Å³¡Ç¿¶Èrn");

printf("XÖá:%ldrn",rm3100.rx);

printf("YÖá:%ldrn",rm3100.ry);

printf("ZÖá:%ldrn",rm3100.rz);

}

After completion, the currently measured magnetic field strength can be printed out through the serial port