mirror of
https://github.com/licsber/micropython.git
synced 2024-09-21 01:20:23 +08:00
74 lines
2.4 KiB
Python
Executable File
74 lines
2.4 KiB
Python
Executable File
"""
|
|
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).
|
|
|
|
See:
|
|
STM32Cube_FW_F4_V1.1.0/Drivers/BSP/Components/lis302dl/lis302dl.h
|
|
STM32Cube_FW_F4_V1.1.0/Drivers/BSP/Components/lis302dl/lis302dl.c
|
|
STM32Cube_FW_F4_V1.1.0/Drivers/BSP/STM32F4-Discovery/stm32f4_discovery.c
|
|
STM32Cube_FW_F4_V1.1.0/Drivers/BSP/STM32F4-Discovery/stm32f4_discovery.h
|
|
STM32Cube_FW_F4_V1.1.0/Drivers/BSP/STM32F4-Discovery/stm32f4_discovery_accelerometer.c
|
|
STM32Cube_FW_F4_V1.1.0/Drivers/BSP/STM32F4-Discovery/stm32f4_discovery_accelerometer.h
|
|
STM32Cube_FW_F4_V1.1.0/Projects/STM32F4-Discovery/Demonstrations/Src/main.c
|
|
"""
|
|
|
|
from pyb import Pin
|
|
from pyb import SPI
|
|
|
|
READWRITE_CMD = const(0x80)
|
|
MULTIPLEBYTE_CMD = const(0x40)
|
|
LIS302DL_WHO_AM_I_ADDR = const(0x0f)
|
|
LIS302DL_WHO_AM_I_VAL = const(0x3b)
|
|
LIS302DL_CTRL_REG1_ADDR = const(0x20)
|
|
LIS302DL_OUT_X = const(0x29)
|
|
# Configuration for 100Hz sampling rate, +-2g range
|
|
LIS302DL_CONF = 0b01000111
|
|
|
|
def signed8(x):
|
|
if x & 0x80:
|
|
return x - 256
|
|
else:
|
|
return x
|
|
|
|
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.wr(LIS302DL_CTRL_REG1_ADDR, bytearray([LIS302DL_CONF]))
|
|
if(self.read_id()[0] != LIS302DL_WHO_AM_I_VAL):
|
|
raise Exception('LIS302DL accelerometer not present')
|
|
|
|
def rd(self, addr, nbytes):
|
|
if nbytes > 1:
|
|
addr |= READWRITE_CMD | MULTIPLEBYTE_CMD
|
|
else:
|
|
addr |= READWRITE_CMD
|
|
self.cs_pin.low()
|
|
self.spi.send(addr)
|
|
buf = self.spi.send_recv(bytearray(nbytes * [0])) # read data, MSB first
|
|
self.cs_pin.high()
|
|
return buf
|
|
|
|
def wr(self, addr, buf):
|
|
if len(buf) > 1:
|
|
addr |= MULTIPLEBYTE_CMD
|
|
self.cs_pin.low()
|
|
self.spi.send(addr)
|
|
for b in buf:
|
|
self.spi.send(b)
|
|
self.cs_pin.high()
|
|
|
|
def read_id(self):
|
|
return self.rd(LIS302DL_WHO_AM_I_ADDR, 1)
|
|
|
|
def get_xyz(self):
|
|
val = self.rd(LIS302DL_OUT_X, 5)
|
|
x = signed8(val[0]) * 18.0 / 1000
|
|
y = signed8(val[2]) * 18.0 / 1000
|
|
z = signed8(val[4]) * 18.0 / 1000
|
|
return [x, y, z]
|