def __init__(self):
self.logger = logging.getLogger('pywws.WeatherStation.CUSBDrive')
self.logger.info('using %s', USBDevice.__module__)
self.dev = USBDevice(0x1941, 0x8021)
class CUSBDrive(object):
"""Low level interface to weather station via USB.
Loosely modeled on a C++ class obtained from
http://site.ambientweatherstore.com/easyweather/ws_1080_2080_protocol.zip.
I don't know the provenance of this, but it looks as if it may
have come from the manufacturer.
"""
EndMark = 0x20
ReadCommand = 0xA1
WriteCommand = 0xA0
WriteCommandWord = 0xA2
def __init__(self):
self.logger = logging.getLogger('pywws.WeatherStation.CUSBDrive')
self.logger.info('using %s', USBDevice.__module__)
self.dev = USBDevice(0x1941, 0x8021)
def read_block(self, address):
"""Read 32 bytes from the weather station.
If the read fails for any reason, :obj:`None` is returned.
:param address: address to read from.
:type address: int
:return: the data from the weather station.
:rtype: list(int)
"""
buf = [
self.ReadCommand,
address // 256,
address % 256,
self.EndMark,
self.ReadCommand,
address // 256,
address % 256,
self.EndMark,
]
if not self.dev.write_data(buf):
return None
return self.dev.read_data(32)
def write_byte(self, address, data):
"""Write a single byte to the weather station.
:param address: address to write to.
:type address: int
:param data: the value to write.
:type data: int
:return: success status.
:rtype: bool
"""
buf = [
self.WriteCommandWord,
address // 256,
address % 256,
self.EndMark,
self.WriteCommandWord,
data,
0,
self.EndMark,
]
if not self.dev.write_data(buf):
return False
buf = self.dev.read_data(8)
if buf is None:
return False
for byte in buf:
if byte != 0xA5:
return False
return True