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# Support for reading acceleration data from an icm20948 chip
#
# Copyright (C) 2024 Paul Hansel <github@paulhansel.com>
# Copyright (C) 2022 Harry Beyel <harry3b9@gmail.com>
# Copyright (C) 2020-2021 Kevin O'Connor <kevin@koconnor.net>
#
# This file may be distributed under the terms of the GNU GPLv3 license.
# From https://invensense.tdk.com/wp-content/uploads/
# 2016/06/DS-000189-ICM-20948-v1.3.pdf
import logging
from . import bus, adxl345, bulk_sensor
ICM20948_ADDR = 0x68
ICM_DEV_IDS = {
0xEA: "icm-20948",
#everything above are normal ICM IDs
}
# ICM20948 registers
REG_DEVID = 0x00 # 0xEA
REG_FIFO_EN = 0x67 # FIFO_EN_2
REG_ACCEL_SMPLRT_DIV1 = 0x10 # MSB
REG_ACCEL_SMPLRT_DIV2 = 0x11 # LSB
REG_ACCEL_CONFIG = 0x14
REG_USER_CTRL = 0x03
REG_PWR_MGMT_1 = 0x06
REG_PWR_MGMT_2 = 0x07
REG_INT_STATUS = 0x19
REG_BANK_SEL = 0x7F
SAMPLE_RATE_DIVS = { 4500: 0x00 }
SET_BANK_0 = 0x00
SET_BANK_1 = 0x10
SET_BANK_2 = 0x20
SET_BANK_3 = 0x30
SET_ACCEL_CONFIG = 0x06 # 16g full scale, 1209Hz BW, 4.5kHz samp rate
SET_PWR_MGMT_1_WAKE = 0x01
SET_PWR_MGMT_1_SLEEP = 0x41
SET_PWR_MGMT_2_ACCEL_ON = 0x07
SET_PWR_MGMT_2_OFF = 0x3F
SET_USER_FIFO_RESET = 0x0E
SET_USER_FIFO_EN = 0x40
SET_ENABLE_FIFO = 0x10
SET_DISABLE_FIFO = 0x00
FREEFALL_ACCEL = 9.80665 * 1000.
# SCALE = 1/2048 g/LSB @16g scale * Earth gravity in mm/s**2
SCALE = 0.00048828125 * FREEFALL_ACCEL
FIFO_SIZE = 512
BATCH_UPDATES = 0.100
# Printer class that controls ICM20948 chip
class ICM20948:
def __init__(self, config):
self.printer = config.get_printer()
adxl345.AccelCommandHelper(config, self)
self.axes_map = adxl345.read_axes_map(config, SCALE, SCALE, SCALE)
self.data_rate = config.getint('rate', 4500)
if self.data_rate not in SAMPLE_RATE_DIVS:
raise config.error("Invalid rate parameter: %d" % (self.data_rate,))
# Setup mcu sensor_icm20948 bulk query code
self.i2c = bus.MCU_I2C_from_config(config,
default_addr=ICM20948_ADDR,
default_speed=400000)
self.mcu = mcu = self.i2c.get_mcu()
self.oid = mcu.create_oid()
self.query_icm20948_cmd = None
mcu.register_config_callback(self._build_config)
# Bulk sample message reading
chip_smooth = self.data_rate * BATCH_UPDATES * 2
self.ffreader = bulk_sensor.FixedFreqReader(mcu, chip_smooth, ">hhh")
self.last_error_count = 0
# Process messages in batches
self.batch_bulk = bulk_sensor.BatchBulkHelper(
self.printer, self._process_batch,
self._start_measurements, self._finish_measurements, BATCH_UPDATES)
self.name = config.get_name().split()[-1]
hdr = ('time', 'x_acceleration', 'y_acceleration', 'z_acceleration')
self.batch_bulk.add_mux_endpoint("icm20948/dump_icm20948", "sensor",
self.name, {'header': hdr})
def _build_config(self):
cmdqueue = self.i2c.get_command_queue()
self.mcu.add_config_cmd("config_icm20948 oid=%d i2c_oid=%d"
% (self.oid, self.i2c.get_oid()))
self.mcu.add_config_cmd("query_icm20948 oid=%d rest_ticks=0"
% (self.oid,), on_restart=True)
self.query_icm20948_cmd = self.mcu.lookup_command(
"query_icm20948 oid=%c rest_ticks=%u", cq=cmdqueue)
self.ffreader.setup_query_command("query_icm20948_status oid=%c",
oid=self.oid, cq=cmdqueue)
def read_reg(self, reg):
params = self.i2c.i2c_read([reg], 1)
return bytearray(params['response'])[0]
def set_reg(self, reg, val, minclock=0):
self.i2c.i2c_write([reg, val & 0xFF], minclock=minclock)
def start_internal_client(self):
aqh = adxl345.AccelQueryHelper(self.printer)
self.batch_bulk.add_client(aqh.handle_batch)
return aqh
# Measurement decoding
def _convert_samples(self, samples):
(x_pos, x_scale), (y_pos, y_scale), (z_pos, z_scale) = self.axes_map
count = 0
for ptime, rx, ry, rz in samples:
raw_xyz = (rx, ry, rz)
x = round(raw_xyz[x_pos] * x_scale, 6)
y = round(raw_xyz[y_pos] * y_scale, 6)
z = round(raw_xyz[z_pos] * z_scale, 6)
samples[count] = (round(ptime, 6), x, y, z)
count += 1
# Start, stop, and process message batches
def _start_measurements(self):
# In case of miswiring, testing ICM20948 device ID prevents treating
# noise or wrong signal as a correctly initialized device
dev_id = self.read_reg(REG_DEVID)
if dev_id not in ICM_DEV_IDS.keys():
raise self.printer.command_error(
"Invalid mpu id (got %x).\n"
"This is generally indicative of connection problems\n"
"(e.g. faulty wiring) or a faulty chip."
% (dev_id))
else:
logging.info("Found %s with id %x"% (ICM_DEV_IDS[dev_id], dev_id))
# Setup chip in requested query rate
self.set_reg(REG_PWR_MGMT_1, SET_PWR_MGMT_1_WAKE)
self.set_reg(REG_PWR_MGMT_2, SET_PWR_MGMT_2_ACCEL_ON)
# Don't add 20ms pause for accelerometer chip wake up
self.read_reg(REG_DEVID) # Dummy read to ensure queues flushed
self.set_reg(REG_ACCEL_SMPLRT_DIV1, SAMPLE_RATE_DIVS[self.data_rate])
self.set_reg(REG_ACCEL_SMPLRT_DIV2, SAMPLE_RATE_DIVS[self.data_rate])
self.set_reg(REG_BANK_SEL, SET_BANK_2)
self.set_reg(REG_ACCEL_CONFIG, SET_ACCEL_CONFIG)
self.set_reg(REG_BANK_SEL, SET_BANK_0)
# Reset fifo
self.set_reg(REG_FIFO_EN, SET_DISABLE_FIFO)
self.set_reg(REG_USER_CTRL, SET_USER_FIFO_RESET)
self.set_reg(REG_USER_CTRL, SET_USER_FIFO_EN)
self.read_reg(REG_INT_STATUS) # clear FIFO overflow flag
# Start bulk reading
rest_ticks = self.mcu.seconds_to_clock(4. / self.data_rate)
self.query_icm20948_cmd.send([self.oid, rest_ticks])
self.set_reg(REG_FIFO_EN, SET_ENABLE_FIFO)
logging.info("ICM20948 starting '%s' measurements", self.name)
# Initialize clock tracking
self.ffreader.note_start()
self.last_error_count = 0
def _finish_measurements(self):
# Halt bulk reading
self.set_reg(REG_FIFO_EN, SET_DISABLE_FIFO)
self.query_icm20948_cmd.send_wait_ack([self.oid, 0])
self.ffreader.note_end()
logging.info("ICM20948 finished '%s' measurements", self.name)
self.set_reg(REG_PWR_MGMT_1, SET_PWR_MGMT_1_SLEEP)
self.set_reg(REG_PWR_MGMT_2, SET_PWR_MGMT_2_OFF)
def _process_batch(self, eventtime):
samples = self.ffreader.pull_samples()
self._convert_samples(samples)
if not samples:
return {}
return {'data': samples, 'errors': self.last_error_count,
'overflows': self.ffreader.get_last_overflows()}
def load_config(config):
return ICM20948(config)
def load_config_prefix(config):
return ICM20948(config)
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