Here is the driver and basic program I use with this chip. It is pure MicroPython - no library. It came from the Waveshare Environment Sensor board.
import time
from machine import Pin, I2C
import math
Gyro = [0,0,0]
Accel = [0,0,0]
Mag = [0,0,0]
pitch = 0.0
roll = 0.0
yaw = 0.0
pu8data=[0,0,0,0,0,0,0,0]
U8tempX=[0,0,0,0,0,0,0,0,0]
U8tempY=[0,0,0,0,0,0,0,0,0]
U8tempZ=[0,0,0,0,0,0,0,0,0]
GyroOffset=[0,0,0]
Ki = 1.0
Kp = 4.50
q0 = 1.0
q1=q2=q3=0.0
angles=[0.0,0.0,0.0]
true =0x01
false =0x00
# define ICM-20948 Device I2C address
I2C_ADD_ICM20948 = 0x68
I2C_ADD_ICM20948_AK09916 = 0x0C
I2C_ADD_ICM20948_AK09916_READ = 0x80
I2C_ADD_ICM20948_AK09916_WRITE = 0x00
# define ICM-20948 Register
# user bank 0 register
REG_ADD_WIA = 0x00
REG_VAL_WIA = 0xEA
REG_ADD_USER_CTRL = 0x03
REG_VAL_BIT_DMP_EN = 0x80
REG_VAL_BIT_FIFO_EN = 0x40
REG_VAL_BIT_I2C_MST_EN = 0x20
REG_VAL_BIT_I2C_IF_DIS = 0x10
REG_VAL_BIT_DMP_RST = 0x08
REG_VAL_BIT_DIAMOND_DMP_RST = 0x04
REG_ADD_PWR_MIGMT_1 = 0x06
REG_VAL_ALL_RGE_RESET = 0x80
REG_VAL_RUN_MODE = 0x01 # Non low-power mode
REG_ADD_LP_CONFIG = 0x05
REG_ADD_PWR_MGMT_1 = 0x06
REG_ADD_PWR_MGMT_2 = 0x07
REG_ADD_ACCEL_XOUT_H = 0x2D
REG_ADD_ACCEL_XOUT_L = 0x2E
REG_ADD_ACCEL_YOUT_H = 0x2F
REG_ADD_ACCEL_YOUT_L = 0x30
REG_ADD_ACCEL_ZOUT_H = 0x31
REG_ADD_ACCEL_ZOUT_L = 0x32
REG_ADD_GYRO_XOUT_H = 0x33
REG_ADD_GYRO_XOUT_L = 0x34
REG_ADD_GYRO_YOUT_H = 0x35
REG_ADD_GYRO_YOUT_L = 0x36
REG_ADD_GYRO_ZOUT_H = 0x37
REG_ADD_GYRO_ZOUT_L = 0x38
REG_ADD_EXT_SENS_DATA_00 = 0x3B
REG_ADD_REG_BANK_SEL = 0x7F
REG_VAL_REG_BANK_0 = 0x00
REG_VAL_REG_BANK_1 = 0x10
REG_VAL_REG_BANK_2 = 0x20
REG_VAL_REG_BANK_3 = 0x30
# user bank 1 register
# user bank 2 register
REG_ADD_GYRO_SMPLRT_DIV = 0x00
REG_ADD_GYRO_CONFIG_1 = 0x01
REG_VAL_BIT_GYRO_DLPCFG_2 = 0x10 # bit[5:3]
REG_VAL_BIT_GYRO_DLPCFG_4 = 0x20 # bit[5:3]
REG_VAL_BIT_GYRO_DLPCFG_6 = 0x30 # bit[5:3]
REG_VAL_BIT_GYRO_FS_250DPS = 0x00 # bit[2:1]
REG_VAL_BIT_GYRO_FS_500DPS = 0x02 # bit[2:1]
REG_VAL_BIT_GYRO_FS_1000DPS = 0x04 # bit[2:1]
REG_VAL_BIT_GYRO_FS_2000DPS = 0x06 # bit[2:1]
REG_VAL_BIT_GYRO_DLPF = 0x01 # bit[0]
REG_ADD_ACCEL_SMPLRT_DIV_2 = 0x11
REG_ADD_ACCEL_CONFIG = 0x14
REG_VAL_BIT_ACCEL_DLPCFG_2 = 0x10 # bit[5:3]
REG_VAL_BIT_ACCEL_DLPCFG_4 = 0x20 # bit[5:3]
REG_VAL_BIT_ACCEL_DLPCFG_6 = 0x30 # bit[5:3]
REG_VAL_BIT_ACCEL_FS_2g = 0x00 # bit[2:1]
REG_VAL_BIT_ACCEL_FS_4g = 0x02 # bit[2:1]
REG_VAL_BIT_ACCEL_FS_8g = 0x04 # bit[2:1]
REG_VAL_BIT_ACCEL_FS_16g = 0x06 # bit[2:1]
REG_VAL_BIT_ACCEL_DLPF = 0x01 # bit[0]
# user bank 3 register
REG_ADD_I2C_SLV0_ADDR = 0x03
REG_ADD_I2C_SLV0_REG = 0x04
REG_ADD_I2C_SLV0_CTRL = 0x05
REG_VAL_BIT_SLV0_EN = 0x80
REG_VAL_BIT_MASK_LEN = 0x07
REG_ADD_I2C_SLV0_DO = 0x06
REG_ADD_I2C_SLV1_ADDR = 0x07
REG_ADD_I2C_SLV1_REG = 0x08
REG_ADD_I2C_SLV1_CTRL = 0x09
REG_ADD_I2C_SLV1_DO = 0x0A
# define ICM-20948 Register end
# define ICM-20948 MAG Register
REG_ADD_MAG_WIA1 = 0x00
REG_VAL_MAG_WIA1 = 0x48
REG_ADD_MAG_WIA2 = 0x01
REG_VAL_MAG_WIA2 = 0x09
REG_ADD_MAG_ST2 = 0x10
REG_ADD_MAG_DATA = 0x11
REG_ADD_MAG_CNTL2 = 0x31
REG_VAL_MAG_MODE_PD = 0x00
REG_VAL_MAG_MODE_SM = 0x01
REG_VAL_MAG_MODE_10HZ = 0x02
REG_VAL_MAG_MODE_20HZ = 0x04
REG_VAL_MAG_MODE_50HZ = 0x05
REG_VAL_MAG_MODE_100HZ = 0x08
REG_VAL_MAG_MODE_ST = 0x10
# define ICM-20948 MAG Register end
MAG_DATA_LEN =6
class ICM20948(object):
def __init__(self,address=I2C_ADD_ICM20948):
self._address = address
self._bus = I2C(0, scl=Pin(21), sda=Pin(20), freq=100000)
bRet=self.icm20948Check() #Initialization of the device multiple times after power on will result in a return error
time.sleep(0.5) #We can skip this detection by delaying it by 500 milliseconds
# user bank 0 register
self._write_byte( REG_ADD_REG_BANK_SEL , REG_VAL_REG_BANK_0)
self._write_byte( REG_ADD_PWR_MIGMT_1 , REG_VAL_ALL_RGE_RESET)
time.sleep(0.1)
self._write_byte( REG_ADD_PWR_MIGMT_1 , REG_VAL_RUN_MODE)
#user bank 2 register
self._write_byte( REG_ADD_REG_BANK_SEL , REG_VAL_REG_BANK_2)
self._write_byte( REG_ADD_GYRO_SMPLRT_DIV , 0x07)
self._write_byte( REG_ADD_GYRO_CONFIG_1 , REG_VAL_BIT_GYRO_DLPCFG_6 | REG_VAL_BIT_GYRO_FS_1000DPS | REG_VAL_BIT_GYRO_DLPF)
self._write_byte( REG_ADD_ACCEL_SMPLRT_DIV_2 , 0x07)
self._write_byte( REG_ADD_ACCEL_CONFIG , REG_VAL_BIT_ACCEL_DLPCFG_6 | REG_VAL_BIT_ACCEL_FS_2g | REG_VAL_BIT_ACCEL_DLPF)
#user bank 0 register
self._write_byte( REG_ADD_REG_BANK_SEL , REG_VAL_REG_BANK_0)
time.sleep(0.1)
self.GyroOffset()
self.MagCheck()
self.WriteSecondary( I2C_ADD_ICM20948_AK09916|I2C_ADD_ICM20948_AK09916_WRITE,REG_ADD_MAG_CNTL2, REG_VAL_MAG_MODE_20HZ)
def Gyro_Accel_Read(self):
self._write_byte( REG_ADD_REG_BANK_SEL , REG_VAL_REG_BANK_0)
data =self._read_block(REG_ADD_ACCEL_XOUT_H, 12)
self._write_byte( REG_ADD_REG_BANK_SEL , REG_VAL_REG_BANK_2)
Accel[0] = (data[0]<<8)|data[1]
Accel[1] = (data[2]<<8)|data[3]
Accel[2] = (data[4]<<8)|data[5]
Gyro[0] = ((data[6]<<8)|data[7]) - GyroOffset[0]
Gyro[1] = ((data[8]<<8)|data[9]) - GyroOffset[1]
Gyro[2] = ((data[10]<<8)|data[11]) - GyroOffset[2]
if Accel[0]>=32767: #Solve the problem that Python shift will not overflow
Accel[0]=Accel[0]-65535
elif Accel[0]<=-32767:
Accel[0]=Accel[0]+65535
if Accel[1]>=32767:
Accel[1]=Accel[1]-65535
elif Accel[1]<=-32767:
Accel[1]=Accel[1]+65535
if Accel[2]>=32767:
Accel[2]=Accel[2]-65535
elif Accel[2]<=-32767:
Accel[2]=Accel[2]+65535
if Gyro[0]>=32767:
Gyro[0]=Gyro[0]-65535
elif Gyro[0]<=-32767:
Gyro[0]=Gyro[0]+65535
if Gyro[1]>=32767:
Gyro[1]=Gyro[1]-65535
elif Gyro[1]<=-32767:
Gyro[1]=Gyro[1]+65535
if Gyro[2]>=32767:
Gyro[2]=Gyro[2]-65535
elif Gyro[2]<=-32767:
Gyro[2]=Gyro[2]+65535
def MagRead(self):
counter=20
while(counter>0):
time.sleep(0.01)
self.icm20948ReadSecondary( I2C_ADD_ICM20948_AK09916|I2C_ADD_ICM20948_AK09916_READ , REG_ADD_MAG_ST2, 1)
if ((pu8data[0] & 0x01)!= 0):
break
counter-=1
if counter!=0:
for i in range(0,8):
self.icm20948ReadSecondary( I2C_ADD_ICM20948_AK09916|I2C_ADD_ICM20948_AK09916_READ , REG_ADD_MAG_DATA , MAG_DATA_LEN)
U8tempX[i] = (pu8data[1]<<8)|pu8data[0]
U8tempY[i] = (pu8data[3]<<8)|pu8data[2]
U8tempZ[i] = (pu8data[5]<<8)|pu8data[4]
Mag[0]=(U8tempX[0]+U8tempX[1]+U8tempX[2]+U8tempX[3]+U8tempX[4]+U8tempX[5]+U8tempX[6]+U8tempX[7])/8
Mag[1]=-(U8tempY[0]+U8tempY[1]+U8tempY[2]+U8tempY[3]+U8tempY[4]+U8tempY[5]+U8tempY[6]+U8tempY[7])/8
Mag[2]=-(U8tempZ[0]+U8tempZ[1]+U8tempZ[2]+U8tempZ[3]+U8tempZ[4]+U8tempZ[5]+U8tempZ[6]+U8tempZ[7])/8
if Mag[0]>=32767: #Solve the problem that Python shift will not overflow
Mag[0]=Mag[0]-65535
elif Mag[0]<=-32767:
Mag[0]=Mag[0]+65535
if Mag[1]>=32767:
Mag[1]=Mag[1]-65535
elif Mag[1]<=-32767:
Mag[1]=Mag[1]+65535
if Mag[2]>=32767:
Mag[2]=Mag[2]-65535
elif Mag[2]<=-32767:
Mag[2]=Mag[2]+65535
def icm20948ReadSecondary(self,u8I2CAddr,u8RegAddr,u8Len):
u8Temp=0
self._write_byte( REG_ADD_REG_BANK_SEL, REG_VAL_REG_BANK_3) #swtich bank3
self._write_byte( REG_ADD_I2C_SLV0_ADDR, u8I2CAddr)
self._write_byte( REG_ADD_I2C_SLV0_REG, u8RegAddr)
self._write_byte( REG_ADD_I2C_SLV0_CTRL, REG_VAL_BIT_SLV0_EN|u8Len)
self._write_byte( REG_ADD_REG_BANK_SEL, REG_VAL_REG_BANK_0) #swtich bank0
u8Temp = self._read_byte(REG_ADD_USER_CTRL)
u8Temp |= REG_VAL_BIT_I2C_MST_EN
self._write_byte( REG_ADD_USER_CTRL, u8Temp)
time.sleep(0.01)
u8Temp &= ~REG_VAL_BIT_I2C_MST_EN
self._write_byte( REG_ADD_USER_CTRL, u8Temp)
for i in range(0,u8Len):
pu8data[i]= self._read_byte( REG_ADD_EXT_SENS_DATA_00+i)
self._write_byte( REG_ADD_REG_BANK_SEL, REG_VAL_REG_BANK_3) #swtich bank3
u8Temp = self._read_byte(REG_ADD_I2C_SLV0_CTRL)
u8Temp &= ~((REG_VAL_BIT_I2C_MST_EN)&(REG_VAL_BIT_MASK_LEN))
self._write_byte( REG_ADD_I2C_SLV0_CTRL, u8Temp)
self._write_byte( REG_ADD_REG_BANK_SEL, REG_VAL_REG_BANK_0) #swtich bank0
def WriteSecondary(self,u8I2CAddr,u8RegAddr,u8data):
u8Temp=0
self._write_byte( REG_ADD_REG_BANK_SEL, REG_VAL_REG_BANK_3) #swtich bank3
self._write_byte( REG_ADD_I2C_SLV1_ADDR, u8I2CAddr)
self._write_byte( REG_ADD_I2C_SLV1_REG, u8RegAddr)
self._write_byte( REG_ADD_I2C_SLV1_DO, u8data)
self._write_byte( REG_ADD_I2C_SLV1_CTRL, REG_VAL_BIT_SLV0_EN|1)
self._write_byte( REG_ADD_REG_BANK_SEL, REG_VAL_REG_BANK_0) #swtich bank0
u8Temp = self._read_byte(REG_ADD_USER_CTRL)
u8Temp |= REG_VAL_BIT_I2C_MST_EN
self._write_byte( REG_ADD_USER_CTRL, u8Temp)
time.sleep(0.01)
u8Temp &= ~REG_VAL_BIT_I2C_MST_EN
self._write_byte( REG_ADD_USER_CTRL, u8Temp)
self._write_byte( REG_ADD_REG_BANK_SEL, REG_VAL_REG_BANK_3) #swtich bank3
u8Temp = self._read_byte(REG_ADD_I2C_SLV0_CTRL)
u8Temp &= ~((REG_VAL_BIT_I2C_MST_EN)&(REG_VAL_BIT_MASK_LEN))
self._write_byte( REG_ADD_I2C_SLV0_CTRL, u8Temp)
self._write_byte( REG_ADD_REG_BANK_SEL, REG_VAL_REG_BANK_0) #swtich bank0
def GyroOffset(self):
s32TempGx = 0
s32TempGy = 0
s32TempGz = 0
for i in range(0,32):
self.Gyro_Accel_Read()
s32TempGx += Gyro[0]
s32TempGy += Gyro[1]
s32TempGz += Gyro[2]
time.sleep(0.01)
GyroOffset[0] = s32TempGx >> 5
GyroOffset[1] = s32TempGy >> 5
GyroOffset[2] = s32TempGz >> 5
def _read_byte(self,cmd):
rdate = self._bus.readfrom_mem(int(self._address), int(cmd), 1)
return rdate[0]
def _read_block(self, reg, length=1):
return self._bus.readfrom_mem(self._address, reg, length)
def _read_u16(self,cmd):
LSB = self._bus.readfrom_mem(self._address,cmd, 1)
MSB = self._bus.readfrom_mem(self._address,cmd+1, 1)
return (MSB << 8) + LSB
def _write_byte(self,cmd,val):
self._bus.writeto_mem(int(self._address), int(cmd), bytes([int(val)]))
time.sleep(0.0001)
def imuAHRSupdata(self,gx, gy,gz,ax,ay,az,mx,my,mz):
norm=0.0
hx = hy = hz = bx = bz = 0.0
vx = vy = vz = wx = wy = wz = 0.0
exInt = eyInt = ezInt = 0.0
ex=ey=ez=0.0
halfT = 0.024
global q0
global q1
global q2
global q3
q0q0 = q0 * q0
q0q1 = q0 * q1
q0q2 = q0 * q2
q0q3 = q0 * q3
q1q1 = q1 * q1
q1q2 = q1 * q2
q1q3 = q1 * q3
q2q2 = q2 * q2
q2q3 = q2 * q3
q3q3 = q3 * q3
norm = float(1/math.sqrt(ax * ax + ay * ay + az * az))
ax = ax * norm
ay = ay * norm
az = az * norm
norm = float(1/math.sqrt(mx * mx + my * my + mz * mz))
mx = mx * norm
my = my * norm
mz = mz * norm
# compute reference direction of flux
hx = 2 * mx * (0.5 - q2q2 - q3q3) + 2 * my * (q1q2 - q0q3) + 2 * mz * (q1q3 + q0q2)
hy = 2 * mx * (q1q2 + q0q3) + 2 * my * (0.5 - q1q1 - q3q3) + 2 * mz * (q2q3 - q0q1)
hz = 2 * mx * (q1q3 - q0q2) + 2 * my * (q2q3 + q0q1) + 2 * mz * (0.5 - q1q1 - q2q2)
bx = math.sqrt((hx * hx) + (hy * hy))
bz = hz
# estimated direction of gravity and flux (v and w)
vx = 2 * (q1q3 - q0q2)
vy = 2 * (q0q1 + q2q3)
vz = q0q0 - q1q1 - q2q2 + q3q3
wx = 2 * bx * (0.5 - q2q2 - q3q3) + 2 * bz * (q1q3 - q0q2)
wy = 2 * bx * (q1q2 - q0q3) + 2 * bz * (q0q1 + q2q3)
wz = 2 * bx * (q0q2 + q1q3) + 2 * bz * (0.5 - q1q1 - q2q2)
# error is sum of cross product between reference direction of fields and direction measured by sensors
ex = (ay * vz - az * vy) + (my * wz - mz * wy)
ey = (az * vx - ax * vz) + (mz * wx - mx * wz)
ez = (ax * vy - ay * vx) + (mx * wy - my * wx)
if (ex != 0.0 and ey != 0.0 and ez != 0.0):
exInt = exInt + ex * Ki * halfT
eyInt = eyInt + ey * Ki * halfT
ezInt = ezInt + ez * Ki * halfT
gx = gx + Kp * ex + exInt
gy = gy + Kp * ey + eyInt
gz = gz + Kp * ez + ezInt
q0 = q0 + (-q1 * gx - q2 * gy - q3 * gz) * halfT
q1 = q1 + (q0 * gx + q2 * gz - q3 * gy) * halfT
q2 = q2 + (q0 * gy - q1 * gz + q3 * gx) * halfT
q3 = q3 + (q0 * gz + q1 * gy - q2 * gx) * halfT
norm = float(1/math.sqrt(q0 * q0 + q1 * q1 + q2 * q2 + q3 * q3))
q0 = q0 * norm
q1 = q1 * norm
q2 = q2 * norm
q3 = q3 * norm
def icm20948Check(self):
bRet=false
if REG_VAL_WIA == self._read_byte(REG_ADD_WIA):
bRet = true
return bRet
def MagCheck(self):
self.icm20948ReadSecondary( I2C_ADD_ICM20948_AK09916|I2C_ADD_ICM20948_AK09916_READ,REG_ADD_MAG_WIA1, 2)
if (pu8data[0] == REG_VAL_MAG_WIA1) and ( pu8data[1] == REG_VAL_MAG_WIA2) :
bRet = true
return bRet
def CalAvgValue(self):
MotionVal = [0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0]
MotionVal[0]=Gyro[0]/32.8
MotionVal[1]=Gyro[1]/32.8
MotionVal[2]=Gyro[2]/32.8
MotionVal[3]=Accel[0]
MotionVal[4]=Accel[1]
MotionVal[5]=Accel[2]
MotionVal[6]=Mag[0]
MotionVal[7]=Mag[1]
MotionVal[8]=Mag[2]
return MotionVal
def getdata(self):
self.Gyro_Accel_Read()
self.MagRead()
MotionVal=[0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0]
MotionVal = self.CalAvgValue()
time.sleep(0.1)
self.imuAHRSupdata(MotionVal[0] * 0.0175, MotionVal[1] * 0.0175,MotionVal[2] * 0.0175,
MotionVal[3],MotionVal[4],MotionVal[5],
MotionVal[6], MotionVal[7], MotionVal[8])
pitch = math.asin(-2 * q1 * q3 + 2 * q0* q2)* 57.3
roll = math.atan2(2 * q2 * q3 + 2 * q0 * q1, -2 * q1 * q1 - 2 * q2* q2 + 1)* 57.3
yaw = math.atan2(-2 * q1 * q2 - 2 * q0 * q3, 2 * q2 * q2 + 2 * q3 * q3 - 1) * 57.3
return [roll,pitch,yaw, Accel[0],Accel[1],Accel[2], Gyro[0],Gyro[1],Gyro[2],Mag[0],Mag[1],Mag[2]]
if __name__ == '__main__':
print("\nSense HAT Test Program ...\n")
icm20948 = ICM20948()
while True:
icm = []
icm = icm20948.getdata()
print("/-------------------------------------------------------------/")
print("Roll = %.2f , Pitch = %.2f , Yaw = %.2f" %(icm[0],icm[1],icm[2]))
print("Acceleration: X = %d, Y = %d, Z = %d" %(icm[3],icm[4],icm[5]))
print("Gyroscope: X = %d , Y = %d , Z = %d" %(icm[6],icm[7],icm[8]))
print("Magnetic: X = %d , Y = %d , Z = %d" %(icm[9],icm[10],icm[11]))
More details here:
Hope this helps
At the end of the Instructable it shows how to sense tilt and shake with a very simple game.
Great chip but the gyroscope and magnetometer are still a work in progress!
I rather like this method of supplying drivers for boards. It means that you can easily build a single program, with its necessary drivers, in MicroPython and it allows you to modify the drivers as necessary as I did here:
to overcome the corruption/communication problem with Pico Explorer.
I believe you learn more if you can follow what is really going on.