Commit 5f0c18e5 authored by Damien George's avatar Damien George
Browse files

Merge pull request #852 from techno/staccel_LIS3DSH

Add LIS3DSH accelometer support to staccel.py
parents 95307431 2b4af549
"""
Driver for accelerometer on STM32F4 Discover board.
Assumes it's a LIS302DL MEMS device.
Sets accelerometer range at +-2g.
Returns list containing X,Y,Z axis acceleration values in 'g' units (9.8m/s^2).
......@@ -20,28 +19,46 @@ from pyb import SPI
READWRITE_CMD = const(0x80)
MULTIPLEBYTE_CMD = const(0x40)
LIS302DL_WHO_AM_I_ADDR = const(0x0f)
WHO_AM_I_ADDR = const(0x0f)
OUT_X_ADDR = const(0x29)
OUT_Y_ADDR = const(0x2b)
OUT_Z_ADDR = const(0x2d)
OUT_T_ADDR = const(0x0c)
LIS302DL_WHO_AM_I_VAL = const(0x3b)
LIS302DL_CTRL_REG1_ADDR = const(0x20)
LIS302DL_OUT_X = const(0x29)
LIS302DL_OUT_Y = const(0x2b)
LIS302DL_OUT_Z = const(0x2d)
# Configuration for 100Hz sampling rate, +-2g range
LIS302DL_CONF = const(0b01000111)
def convert_raw_to_g(x):
if x & 0x80:
x = x - 256
return x * 18 / 1000
LIS3DSH_WHO_AM_I_VAL = const(0x3f)
LIS3DSH_CTRL_REG4_ADDR = const(0x20)
LIS3DSH_CTRL_REG5_ADDR = const(0x24)
# Configuration for 100Hz sampling rate, +-2g range
LIS3DSH_CTRL_REG4_CONF = const(0b01100111)
LIS3DSH_CTRL_REG5_CONF = const(0b00000000)
class STAccel:
def __init__(self):
self.cs_pin = Pin('PE3', Pin.OUT_PP, Pin.PULL_NONE)
self.cs_pin.high()
self.spi = SPI(1, SPI.MASTER, baudrate=328125, polarity=0, phase=1, bits=8)
self.who_am_i = self.read_id()
if self.who_am_i == LIS302DL_WHO_AM_I_VAL:
self.write_bytes(LIS302DL_CTRL_REG1_ADDR, bytearray([LIS302DL_CONF]))
if self.read_id() != LIS302DL_WHO_AM_I_VAL:
raise Exception('LIS302DL accelerometer not present')
self.sensitivity = 18
elif self.who_am_i == LIS3DSH_WHO_AM_I_VAL:
self.write_bytes(LIS3DSH_CTRL_REG4_ADDR, bytearray([LIS3DSH_CTRL_REG4_CONF]))
self.write_bytes(LIS3DSH_CTRL_REG5_ADDR, bytearray([LIS3DSH_CTRL_REG5_CONF]))
self.sensitivity = 0.06 * 256
else:
raise Exception('LIS302DL or LIS3DSH accelerometer not present')
def convert_raw_to_g(self, x):
if x & 0x80:
x = x - 256
return x * self.sensitivity / 1000
def read_bytes(self, addr, nbytes):
if nbytes > 1:
......@@ -65,19 +82,16 @@ class STAccel:
self.cs_pin.high()
def read_id(self):
return self.read_bytes(LIS302DL_WHO_AM_I_ADDR, 1)[0]
return self.read_bytes(WHO_AM_I_ADDR, 1)[0]
def x(self):
return convert_raw_to_g(self.read_bytes(LIS302DL_OUT_X, 1)[0])
return self.convert_raw_to_g(self.read_bytes(OUT_X_ADDR, 1)[0])
def y(self):
return convert_raw_to_g(self.read_bytes(LIS302DL_OUT_Y, 1)[0])
return self.convert_raw_to_g(self.read_bytes(OUT_Y_ADDR, 1)[0])
def z(self):
return convert_raw_to_g(self.read_bytes(LIS302DL_OUT_Z, 1)[0])
return self.convert_raw_to_g(self.read_bytes(OUT_Z_ADDR, 1)[0])
def xyz(self):
val = self.read_bytes(LIS302DL_OUT_X, 5)
return [convert_raw_to_g(val[0]),
convert_raw_to_g(val[2]),
convert_raw_to_g(val[4])]
return (self.x(), self.y(), self.z())
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