# Support for reading acceleration data from an adxl345 chip
#
# Copyright (C) 2020-2021 Kevin O'Connor <kevin@koconnor.net>
#
# This file may be distributed under the terms of the GNU GPLv3 license.
import logging, time, collections, threading, multiprocessing, os
from . import bus, motion_report
# ADXL345 registers
REG_DEVID = 0x00
REG_BW_RATE = 0x2C
REG_POWER_CTL = 0x2D
REG_DATA_FORMAT = 0x31
REG_FIFO_CTL = 0x38
REG_MOD_READ = 0x80
REG_MOD_MULTI = 0x40
QUERY_RATES = {
25: 0x8, 50: 0x9, 100: 0xa, 200: 0xb, 400: 0xc,
800: 0xd, 1600: 0xe, 3200: 0xf,
}
ADXL345_DEV_ID = 0xe5
SET_FIFO_CTL = 0x90
FREEFALL_ACCEL = 9.80665 * 1000.
SCALE = 0.0039 * FREEFALL_ACCEL # 3.9mg/LSB * Earth gravity in mm/s**2
Accel_Measurement = collections.namedtuple(
'Accel_Measurement', ('time', 'accel_x', 'accel_y', 'accel_z'))
# Helper class to obtain measurements
class ADXL345QueryHelper:
def __init__(self, printer, cconn):
self.printer = printer
self.cconn = cconn
print_time = printer.lookup_object('toolhead').get_last_move_time()
self.request_start_time = self.request_end_time = print_time
self.samples = []
def finish_measurements(self):
toolhead = self.printer.lookup_object('toolhead')
self.request_end_time = toolhead.get_last_move_time()
toolhead.wait_moves()
self.cconn.finalize()
def decode_samples(self):
raw_samples = self.cconn.get_messages()
if not raw_samples:
return self.samples
total = sum([len(m['params']['data']) for m in raw_samples])
count = 0
self.samples = samples = [None] * total
for msg in raw_samples:
for samp_time, x, y, z in msg['params']['data']:
if samp_time < self.request_start_time:
continue
if samp_time > self.request_end_time:
break
samples[count] = Accel_Measurement(samp_time, x, y, z)
count += 1
del samples[count:]
return self.samples
def write_to_file(self, filename):
def write_impl():
try:
# Try to re-nice writing process
os.nice(20)
except:
pass
f = open(filename, "w")
f.write("#time,accel_x,accel_y,accel_z\n")
samples = self.samples or self.decode_samples()
for t, accel_x, accel_y, accel_z in samples:
f.write("%.6f,%.6f,%.6f,%.6f\n" % (
t, accel_x, accel_y, accel_z))
f.close()
write_proc = multiprocessing.Process(target=write_impl)
write_proc.daemon = True
write_proc.start()
# Helper class for G-Code commands
class ADXLCommandHelper:
def __init__(self, config, chip):
self.printer = config.get_printer()
self.chip = chip
self.bg_client = None
self.name = config.get_name().split()[-1]
self.register_commands(self.name)
if self.name == "adxl345":
self.register_commands(None)
def register_commands(self, name):
# Register commands
gcode = self.printer.lookup_object('gcode')
gcode.register_mux_command("ACCELEROMETER_MEASURE", "CHIP", name,
self.cmd_ACCELEROMETER_MEASURE,
desc=self.cmd_ACCELEROMETER_MEASURE_help)
gcode.register_mux_command("ACCELEROMETER_QUERY", "CHIP", name,
self.cmd_ACCELEROMETER_QUERY,
desc=self.cmd_ACCELEROMETER_QUERY_help)
gcode.register_mux_command("ADXL345_DEBUG_READ", "CHIP", name,
self.cmd_ADXL345_DEBUG_READ,
desc=self.cmd_ADXL345_DEBUG_READ_help)
gcode.register_mux_command("ADXL345_DEBUG_WRITE", "CHIP", name,
self.cmd_ADXL345_DEBUG_WRITE,
desc=self.cmd_ADXL345_DEBUG_WRITE_help)
cmd_ACCELEROMETER_MEASURE_help = "Start/stop accelerometer"
def cmd_ACCELEROMETER_MEASURE(self, gcmd):
if not self.chip.is_measuring():
# Start measurements
self.bg_client = self.chip.start_internal_client()
gcmd.respond_info("adxl345 measurements started")
return
if self.bg_client is None:
raise gcmd.error("adxl345 measurements in progress")
# End measurements
name = gcmd.get("NAME", time.strftime("%Y%m%d_%H%M%S"))
if not name.replace('-', '').replace('_', '').isalnum():
raise gcmd.error("Invalid adxl345 NAME parameter")
bg_client = self.bg_client
self.bg_client = None
bg_client.finish_measurements()
# Write data to file
if self.name == "adxl345":
filename = "/tmp/adxl345-%s.csv" % (name,)
else:
filename = "/tmp/adxl345-%s-%s.csv" % (self.name, name,)
bg_client.write_to_file(filename)
gcmd.respond_info("Writing raw accelerometer data to %s file"
% (filename,))
cmd_ACCELEROMETER_QUERY_help = "Query accelerometer for the current values"
def cmd_ACCELEROMETER_QUERY(self, gcmd):
if self.chip.is_measuring():
raise gcmd.error("adxl345 measurements in progress")
aclient = self.chip.start_internal_client()
self.printer.lookup_object('toolhead').dwell(1.)
aclient.finish_measurements()
values = aclient.decode_samples()
if not values:
raise gcmd.error("No adxl345 measurements found")
_, accel_x, accel_y, accel_z = values[-1]
gcmd.respond_info("adxl345 values (x, y, z): %.6f, %.6f, %.6f"
% (accel_x, accel_y, accel_z))
cmd_ADXL345_DEBUG_READ_help = "Query accelerometer register (for debugging)"
def cmd_ADXL345_DEBUG_READ(self, gcmd):
if self.chip.is_measuring():
raise gcmd.error("adxl345 measurements in progress")
reg = gcmd.get("REG", minval=29, maxval=57, parser=lambda x: int(x, 0))
val = self.chip.read_reg(reg)
gcmd.respond_info("ADXL345 REG[0x%x] = 0x%x" % (reg, val))
cmd_ADXL345_DEBUG_WRITE_help = "Set accelerometer register (for debugging)"
def cmd_ADXL345_DEBUG_WRITE(self, gcmd):
if self.chip.is_measuring():
raise gcmd.error("adxl345 measurements in progress")
reg = gcmd.get("REG", minval=29, maxval=57, parser=lambda x: int(x, 0))
val = gcmd.get("VAL", minval=0, maxval=255, parser=lambda x: int(x, 0))
self.chip.set_reg(reg, val)
# Helper class for chip clock synchronization via linear regression
class ClockSyncRegression:
def __init__(self, mcu, chip_clock_smooth, decay = 1. / 20.):
self.mcu = mcu
self.chip_clock_smooth = chip_clock_smooth
self.decay = decay
self.last_chip_clock = self.last_exp_mcu_clock = 0.
self.mcu_clock_avg = self.mcu_clock_variance = 0.
self.chip_clock_avg = self.chip_clock_covariance = 0.
def reset(self, mcu_clock, chip_clock):
self.mcu_clock_avg = self.last_mcu_clock = mcu_clock
self.chip_clock_avg = chip_clock
self.mcu_clock_variance = self.chip_clock_covariance = 0.
self.last_chip_clock = self.last_exp_mcu_clock = 0.
def update(self, mcu_clock, chip_clock):
# Update linear regression
decay = self.decay
diff_mcu_clock = mcu_clock - self.mcu_clock_avg
self.mcu_clock_avg += decay * diff_mcu_clock
self.mcu_clock_variance = (1. - decay) * (
self.mcu_clock_variance + diff_mcu_clock**2 * decay)
diff_chip_clock = chip_clock - self.chip_clock_avg
self.chip_clock_avg += decay * diff_chip_clock
self.chip_clock_covariance = (1. - decay) * (
self.chip_clock_covariance + diff_mcu_clock*diff_chip_clock*decay)
def set_last_chip_clock(self, chip_clock):
base_mcu, base_chip, inv_cfreq = self.get_clock_translation()
self.last_chip_clock = chip_clock
self.last_exp_mcu_clock = base_mcu + (chip_clock-base_chip) * inv_cfreq
def get_clock_translation(self):
inv_chip_freq = self.mcu_clock_variance / self.chip_clock_covariance
if not self.last_chip_clock:
return self.mcu_clock_avg, self.chip_clock_avg, inv_chip_freq
# Find mcu clock associated with future chip_clock
s_chip_clock = self.last_chip_clock + self.chip_clock_smooth
scdiff = s_chip_clock - self.chip_clock_avg
s_mcu_clock = self.mcu_clock_avg + scdiff * inv_chip_freq
# Calculate frequency to converge at future point
mdiff = s_mcu_clock - self.last_exp_mcu_clock
s_inv_chip_freq = mdiff / self.chip_clock_smooth
return self.last_exp_mcu_clock, self.last_chip_clock, s_inv_chip_freq
def get_time_translation(self):
base_mcu, base_chip, inv_cfreq = self.get_clock_translation()
clock_to_print_time = self.mcu.clock_to_print_time
base_time = clock_to_print_time(base_mcu)
inv_freq = clock_to_print_time(base_mcu + inv_cfreq) - base_time
return base_time, base_chip, inv_freq
MIN_MSG_TIME = 0.100
BYTES_PER_SAMPLE = 5
SAMPLES_PER_BLOCK = 10
# Printer class that controls ADXL345 chip
class ADXL345:
def __init__(self, config):
self.printer = config.get_printer()
ADXLCommandHelper(config, self)
self.query_rate = 0
am = {'x': (0, SCALE), 'y': (1, SCALE), 'z': (2, SCALE),
'-x': (0, -SCALE), '-y': (1, -SCALE), '-z': (2, -SCALE)}
axes_map = config.getlist('axes_map', ('x','y','z'), count=3)
if any([a not in am for a in axes_map]):
raise config.error("Invalid adxl345 axes_map parameter")
self.axes_map = [am[a.strip()] for a in axes_map]
self.data_rate = config.getint('rate', 3200)
if self.data_rate not in QUERY_RATES:
raise config.error("Invalid rate parameter: %d" % (self.data_rate,))
# Measurement storage (accessed from background thread)
self.lock = threading.Lock()
self.raw_samples = []
# Setup mcu sensor_adxl345 bulk query code
self.spi = bus.MCU_SPI_from_config(config, 3, default_speed=5000000)
self.mcu = mcu = self.spi.get_mcu()
self.oid = oid = mcu.create_oid()
self.query_adxl345_cmd = self.query_adxl345_end_cmd = None
self.query_adxl345_status_cmd = None
mcu.add_config_cmd("config_adxl345 oid=%d spi_oid=%d"
% (oid, self.spi.get_oid()))
mcu.add_config_cmd("query_adxl345 oid=%d clock=0 rest_ticks=0"
% (oid,), on_restart=True)
mcu.register_config_callback(self._build_config)
mcu.register_response(self._handle_adxl345_data, "adxl345_data", oid)
# Clock tracking
self.last_sequence = self.max_query_duration = 0
self.last_limit_count = self.last_error_count = 0
self.clock_sync = ClockSyncRegression(self.mcu, 640)
# API server endpoints
self.api_dump = motion_report.APIDumpHelper(
self.printer, self._api_update, self._api_startstop, 0.100)
self.name = config.get_name().split()[-1]
wh = self.printer.lookup_object('webhooks')
wh.register_mux_endpoint("adxl345/dump_adxl345", "sensor", self.name,
self._handle_dump_adxl345)
def _build_config(self):
cmdqueue = self.spi.get_command_queue()
self.query_adxl345_cmd = self.mcu.lookup_command(
"query_adxl345 oid=%c clock=%u rest_ticks=%u", cq=cmdqueue)
self.query_adxl345_end_cmd = self.mcu.lookup_query_command(
"query_adxl345 oid=%c clock=%u rest_ticks=%u",
"adxl345_status oid=%c clock=%u query_ticks=%u next_sequence=%hu"
" buffered=%c fifo=%c limit_count=%hu", oid=self.oid, cq=cmdqueue)
self.query_adxl345_status_cmd = self.mcu.lookup_query_command(
"query_adxl345_status oid=%c",
"adxl345_status oid=%c clock=%u query_ticks=%u next_sequence=%hu"
" buffered=%c fifo=%c limit_count=%hu", oid=self.oid, cq=cmdqueue)
def read_reg(self, reg):
params = self.spi.spi_transfer([reg | REG_MOD_READ, 0x00])
response = bytearray(params['response'])
return response[1]
def set_reg(self, reg, val, minclock=0):
self.spi.spi_send([reg, val & 0xFF], minclock=minclock)
stored_val = self.read_reg(reg)
if stored_val != val:
raise self.printer.command_error(
"Failed to set ADXL345 register [0x%x] to 0x%x: got 0x%x. "
"This is generally indicative of connection problems "
"(e.g. faulty wiring) or a faulty adxl345 chip." % (
reg, val, stored_val))
# Measurement collection
def is_measuring(self):
return self.query_rate > 0
def _handle_adxl345_data(self, params):
with self.lock:
self.raw_samples.append(params)
def _extract_samples(self, raw_samples):
# Load variables to optimize inner loop below
(x_pos, x_scale), (y_pos, y_scale), (z_pos, z_scale) = self.axes_map
last_sequence = self.last_sequence
time_base, chip_base, inv_freq = self.clock_sync.get_time_translation()
# Process every message in raw_samples
count = seq = 0
samples = [None] * (len(raw_samples) * SAMPLES_PER_BLOCK)
for params in raw_samples:
seq_diff = (last_sequence - params['sequence']) & 0xffff
seq_diff -= (seq_diff & 0x8000) << 1
seq = last_sequence - seq_diff
d = bytearray(params['data'])
msg_cdiff = seq * SAMPLES_PER_BLOCK - chip_base
for i in range(len(d) // BYTES_PER_SAMPLE):
d_xyz = d[i*BYTES_PER_SAMPLE:(i+1)*BYTES_PER_SAMPLE]
xlow, ylow, zlow, xzhigh, yzhigh = d_xyz
if yzhigh & 0x80:
self.last_error_count += 1
continue
rx = (xlow | ((xzhigh & 0x1f) << 8)) - ((xzhigh & 0x10) << 9)
ry = (ylow | ((yzhigh & 0x1f) << 8)) - ((yzhigh & 0x10) << 9)
rz = ((zlow | ((xzhigh & 0xe0) << 3) | ((yzhigh & 0xe0) << 6))
- ((yzhigh & 0x40) << 7))
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)
ptime = round(time_base + (msg_cdiff + i) * inv_freq, 6)
samples[count] = (ptime, x, y, z)
count += 1
self.clock_sync.set_last_chip_clock(seq * SAMPLES_PER_BLOCK + i)
del samples[count:]
return samples
def _update_clock(self, minclock=0):
# Query current state
for retry in range(5):
params = self.query_adxl345_status_cmd.send([self.oid],
minclock=minclock)
fifo = params['fifo'] & 0x7f
if fifo <= 32:
break
else:
raise self.printer.command_error("Unable to query adxl345 fifo")
mcu_clock = self.mcu.clock32_to_clock64(params['clock'])
sequence = (self.last_sequence & ~0xffff) | params['next_sequence']
if sequence < self.last_sequence:
sequence += 0x10000
self.last_sequence = sequence
buffered = params['buffered']
limit_count = (self.last_limit_count & ~0xffff) | params['limit_count']
if limit_count < self.last_limit_count:
limit_count += 0x10000
self.last_limit_count = limit_count
duration = params['query_ticks']
if duration > self.max_query_duration:
# Skip measurement as a high query time could skew clock tracking
self.max_query_duration = max(2 * self.max_query_duration,
self.mcu.seconds_to_clock(.000005))
return
self.max_query_duration = 2 * duration
msg_count = (sequence * SAMPLES_PER_BLOCK
+ buffered // BYTES_PER_SAMPLE + fifo)
# The "chip clock" is the message counter plus .5 for average
# inaccuracy of query responses and plus .5 for assumed offset
# of adxl345 hw processing time.
chip_clock = msg_count + 1
self.clock_sync.update(mcu_clock + duration // 2, chip_clock)
def _start_measurements(self):
if self.is_measuring():
return
# In case of miswiring, testing ADXL345 device ID prevents treating
# noise or wrong signal as a correctly initialized device
dev_id = self.read_reg(REG_DEVID)
if dev_id != ADXL345_DEV_ID:
raise self.printer.command_error("Invalid adxl345 id (got %x vs %x)"
% (dev_id, ADXL345_DEV_ID))
# Setup chip in requested query rate
self.set_reg(REG_POWER_CTL, 0x00)
self.set_reg(REG_DATA_FORMAT, 0x0B)
self.set_reg(REG_FIFO_CTL, 0x00)
self.set_reg(REG_BW_RATE, QUERY_RATES[self.data_rate])
self.set_reg(REG_FIFO_CTL, SET_FIFO_CTL)
# Setup samples
with self.lock:
self.raw_samples = []
# Start bulk reading
systime = self.printer.get_reactor().monotonic()
print_time = self.mcu.estimated_print_time(systime) + MIN_MSG_TIME
reqclock = self.mcu.print_time_to_clock(print_time)
rest_ticks = self.mcu.seconds_to_clock(4. / self.data_rate)
self.query_rate = self.data_rate
self.query_adxl345_cmd.send([self.oid, reqclock, rest_ticks],
reqclock=reqclock)
logging.info("ADXL345 starting '%s' measurements", self.name)
# Initialize clock tracking
self.last_sequence = 0
self.last_limit_count = self.last_error_count = 0
self.clock_sync.reset(reqclock, 0)
self.max_query_duration = 1 << 31
self._update_clock(minclock=reqclock)
self.max_query_duration = 1 << 31
def _finish_measurements(self):
if not self.is_measuring():
return
# Halt bulk reading
params = self.query_adxl345_end_cmd.send([self.oid, 0, 0])
self.query_rate = 0
with self.lock:
self.raw_samples = []
logging.info("ADXL345 finished '%s' measurements", self.name)
# API interface
def _api_update(self, eventtime):
self._update_clock()
with self.lock:
raw_samples = self.raw_samples
self.raw_samples = []
if not raw_samples:
return {}
samples = self._extract_samples(raw_samples)
if not samples:
return {}
return {'data': samples, 'errors': self.last_error_count,
'overflows': self.last_limit_count}
def _api_startstop(self, is_start):
if is_start:
self._start_measurements()
else:
self._finish_measurements()
def _handle_dump_adxl345(self, web_request):
self.api_dump.add_client(web_request)
hdr = ('time', 'x_acceleration', 'y_acceleration', 'z_acceleration')
web_request.send({'header': hdr})
def start_internal_client(self):
if self.is_measuring():
raise self.printer.command_error(
"ADXL345 measurement already in progress")
cconn = self.api_dump.add_internal_client()
return ADXL345QueryHelper(self.printer, cconn)
def load_config(config):
return ADXL345(config)
def load_config_prefix(config):
return ADXL345(config)