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# -*- coding: utf-8 -*-
"""Driver for SD CodeFree devices by SD Biosensor.
For SD Biosensor glucometers using the serial interface.
Supported features:
- get readings, including pre-/post-meal notes;
- set date and time.
Expected device path: /dev/ttyUSB0 or similar serial port device.
IMPORTANT NOTE: the glucometer can be connected before starting the program, but
it has to be turned on when the program asks you to.
"""
__author__ = 'Diego Elio Pettenò'
__email__ = 'flameeyes@flameeyes.eu'
__copyright__ = 'Copyright © 2017, Diego Elio Pettenò'
__license__ = 'MIT'
import binascii
import datetime
import enum
import functools
import logging
import operator
import construct
from glucometerutils import common
from glucometerutils import exceptions
from glucometerutils.support import serial
def xor_checksum(msg):
return functools.reduce(operator.xor, msg)
class Direction(enum.Enum):
In = 0x20
Out = 0x10
_PACKET = construct.Struct(
'stx' / construct.Const(construct.Byte, 0x53),
'direction' / construct.SymmetricMapping(
construct.Byte,
{e: e.value for e in Direction}),
'length' / construct.Rebuild(
construct.Byte, lambda ctx: len(ctx.message) + 2),
'message' / construct.Bytes(length=lambda ctx: ctx.length - 2),
'checksum' / construct.Checksum(
construct.Byte, xor_checksum, construct.this.message),
'etx' / construct.Const(construct.Byte, 0xAA)
)
_FIRST_MESSAGE = construct.Struct(
construct.Const(construct.Byte, 0x30),
'count' / construct.Int16ub,
construct.Const(construct.Byte, 0xAA)[19])
_CHALLENGE_PACKET_FULL = b'\x53\x20\x04\x10\x30\x20\xAA'
_RESPONSE_MESSAGE = b'\x10\x40'
_DATE_SET_MESSAGE = b'\x10\x10'
_DISCONNECT_MESSAGE = b'\x10\x60'
_DISCONNECTED_MESSAGE = b'\x10\x70'
_FETCH_MESSAGE = b'\x10\x60'
_MEAL_FLAG = {
common.Meal.NONE: 0x00,
common.Meal.BEFORE: 0x10,
common.Meal.AFTER: 0x20,
}
_READING = construct.Struct(
construct.Byte[2],
'year' / construct.Byte,
'month' / construct.Byte,
'day' / construct.Byte,
'hour' / construct.Byte,
'minute' / construct.Byte,
'value' / construct.Int16ub,
'meal' / construct.SymmetricMapping(
construct.Byte, _MEAL_FLAG),
construct.Byte[7],
)
class Device(serial.SerialDevice):
BAUDRATE = 38400
DEFAULT_CABLE_ID = '10c4:ea60' # Generic cable.
TIMEOUT = 300 # We need to wait for data from the device.
def read_message(self):
pkt = _PACKET.parse_stream(self.serial_)
logging.debug('received packet: %r', pkt)
return pkt.message
def wait_and_ready(self):
challenge = self.serial_.read(1)
# The first packet read may have a prefixed zero, it might be a bug in
# the cp210x driver or device, but discard it if found.
if challenge == b'\0':
logging.debug('spurious null byte received')
challege = self.serial_.read(1)
if challenge != b'\x53':
raise exceptions.ConnectionFailed(
message='Unexpected starting bytes %r' % challenge)
challenge += self.serial_.read(6)
if challenge != _CHALLENGE_PACKET_FULL:
raise exceptions.ConnectionFailed(
message='Unexpected challenge %r' % challenge)
logging.debug(
'challenge packet received: %s', binascii.hexlify(challenge))
self.send_message(_RESPONSE_MESSAGE)
# The first packet only contains the counter of how many readings are
# available.
first_message = _FIRST_MESSAGE.parse(self.read_message())
logging.debug('received first message: %r', first_message)
return first_message.count
def send_message(self, message):
pkt = _PACKET.build({
'message': message,
'direction': Direction.Out
})
logging.debug('sending packet: %s', binascii.hexlify(pkt))
self.serial_.write(pkt)
def connect(self):
print("Please connect and turn on the device.")
def disconnect(self):
self.send_message(_DISCONNECT_MESSAGE)
response = self.read_message()
if response != _DISCONNECTED_MESSAGE:
raise exceptions.InvalidResponse(response=response)
def get_meter_info(self):
return common.MeterInfo('SD CodeFree glucometer')
def get_version(self):
raise NotImplementedError
def get_serial_number(self):
raise NotImplementedError
def get_glucose_unit(self):
# Device does not provide information on glucose unit.
return common.Unit.MG_DL
def get_datetime(self):
raise NotImplementedError
def set_datetime(self, date=datetime.datetime.now()):
setdatecmd = date.strftime('ADATE%Y%m%d%H%M').encode('ascii')
# Ignore the readings count.
self.wait_and_ready()
self.send_message(setdatecmd)
response = self.read_message()
if response != _DATE_SET_MESSAGE:
raise exceptions.InvalidResponse(response=response)
# The date we return should only include up to minute, unfortunately.
return datetime.datetime(date.year, date.month, date.day,
date.hour, date.minute)
def zero_log(self):
raise NotImplementedError
def get_readings(self):
count = self.wait_and_ready()
for _ in range(count):
self.send_message(_FETCH_MESSAGE)
message = self.read_message()
r = _READING.parse(message)
logging.debug('received reading: %r', r)
yield common.GlucoseReading(
datetime.datetime(
2000 + r.year, r.month, r.day, r.hour, r.minute),
r.value, meal=r.meal)
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