Posted on November 23, 2017 at 04:12Now I see.
About self test , I have tested my sensor , 10 times self testing , only 2~3 times successful, my self test code listed below , is there some thing wrong in the code?
Self-test0 �?self-test 1 is be mentioned on page 37 of the datasheet , what is the difference of
self-test0 and self-test 1 ? thanks�?
uint8_t ACC_selftest(void)
{
uint8_t i;
int16_t Gx_no_st,Gy_no_st,Gz_no_st,Gx_st,Gy_st,Gz_st,ST_x,ST_y,ST_z;
AxesRaw_t acc_data[32];
//---InitializeSensor,turn on sensor,enableX/Y/Zaxes.?SetBDU=1,FS=2G, NormalMode,ODR=50Hz
if (!(LIS3DH_WriteReg(0x21, 0x00)))
return MEMS_ERROR;
if (!(LIS3DH_WriteReg(0x22, 0x00)))
return MEMS_ERROR;
if (!(LIS3DH_WriteReg(0x23, 0x80))) //A0
return MEMS_ERROR;
if (!(LIS3DH_WriteReg(0x20, 0x47))) //6F
return MEMS_ERROR;
// GYRO is in power down mode after power up
//set the control register (24h) to Cut-Off Frequency = 50Hz
// Write(0x24, 0x02);
// set the control register (23h) to ±2000dps FS, self-test0 mode with BDU bit enabled
//Write(0x23, 0xA0);
// set the control register (20h) to 200Hz ODR with X/Y/Z axis enabled.
//Write(0x20, 0x6F);
//Wait for 800mS for the gyroscope to be stabilized [2]
Delay(0x2000);
// read the gyroscope data 5 times in self-test0 mode
for (i = 0; i < 5; i++)
{
LIS3DH_GetAccAxesRaw(&acc_data[i]);
}
// average the raw data
Gx_no_st = (acc_data[0].AXIS_X + acc_data[1].AXIS_X + acc_data[2].AXIS_X + acc_data[3].AXIS_X + acc_data[4].AXIS_X) / 5;
Gy_no_st = (acc_data[0].AXIS_Y + acc_data[1].AXIS_Y + acc_data[2].AXIS_Y + acc_data[3].AXIS_Y + acc_data[4].AXIS_Y) / 5;
Gz_no_st = (acc_data[0].AXIS_Z + acc_data[1].AXIS_Z + acc_data[2].AXIS_Z + acc_data[3].AXIS_Z + acc_data[4].AXIS_Z) / 5;
// enable self-test 0 at +/-2000dps FS with BDU enabled, Wait for 60mS for the gyroscope to be stabilized
//Write(0x23, 0xA2);
//REG4:---selftest'
LIS3DH_SetSelfTest(LIS3DH_SELF_TEST_0);
// read the gyroscope data 5 times in self-test0 mode
for (i = 0; i < 5; i++)
{
LIS3DH_GetAccAxesRaw(&acc_data[i]);
}
// average the raw data
Gx_st = (acc_data[0].AXIS_X + acc_data[1].AXIS_X + acc_data[2].AXIS_X + acc_data[3].AXIS_X + acc_data[4].AXIS_X) / 5;
Gy_st = (acc_data[0].AXIS_Y + acc_data[1].AXIS_Y + acc_data[2].AXIS_Y + acc_data[3].AXIS_Y + acc_data[4].AXIS_Y) / 5;
Gz_st = (acc_data[0].AXIS_Z + acc_data[1].AXIS_Z + acc_data[2].AXIS_Z + acc_data[3].AXIS_Z + acc_data[4].AXIS_Z) / 5;
// calculate the absolute self-test values of with self-test minus without self-test
ST_x = abs(Gx_st - Gx_no_st);
ST_y = abs(Gy_st - Gy_no_st);
ST_z = abs(Gz_st - Gz_no_st);
//
if ((ST_x <= 360) && (ST_y <= 360) && (ST_z <= 360) && (ST_x >= 17) && (ST_y >= 17) && (ST_z >= 17)){ // 60mg,17,360 need be chaeck !!!!!
//The gyroscope passes;
return MEMS_SUCCESS;
}
else{
//The gyroscope fails;
return MEMS_ERROR;
}
}
