def writeMessage(self,
messageID,
param1=0,
param2=0,
destID=c.GENERIC_USB_ID,
sourceID=c.HOST_CONTROLLER_ID,
dataPacket=None):
""" Send message to device given messageID, parameters 1 & 2, destination and sourceID ID, and optional data packet,
where dataPacket is an array of numeric values. The method converts all the values to hex according to the protocol
specification for the message, and sends this to the device."""
if dataPacket != None:
# If a data packet is included then header consists of concatenation of: messageID (2 bytes),number of bytes in dataPacket (2 bytes), destination byte with MSB=1 (i.e. or'd with 0x80), sourceID byte
try:
dataPacketStr = pack(c.getPacketStruct(messageID), *dataPacket)
except error as e:
raise error, "Error packing message " + hex(
messageID
) + "; probably the packet structure is recorded incorrectly in c.getPacketStruct()"
message = pack(c.HEADER_FORMAT_WITH_DATA, messageID,
len(dataPacketStr), destID | 0x80,
sourceID) + dataPacketStr
else:
# If no data packet then header consists of concatenation of: messageID (2 bytes),param 1 byte, param2 bytes,destination byte, sourceID byte
message = pack(c.HEADER_FORMAT_WITHOUT_DATA, messageID, param1,
param2, destID, sourceID)
if DEBUG_MODE: self.disp(message, "TX: ")
numBytesWritten = self.device.write(message)
def writeMessage(self,messageID,param1=0,param2=0,destID=c.GENERIC_USB_ID,sourceID=c.HOST_CONTROLLER_ID,dataPacket=None):
""" Send message to device given messageID, parameters 1 & 2, destination and sourceID ID, and optional data packet,
where dataPacket is an array of numeric values. The method converts all the values to hex according to the protocol
specification for the message, and sends this to the device."""
if dataPacket!=None:
# If a data packet is included then header consists of concatenation of: messageID (2 bytes),number of bytes in dataPacket (2 bytes), destination byte with MSB=1 (i.e. or'd with 0x80), sourceID byte
try:
dataPacketStr=pack(c.getPacketStruct(messageID) , *dataPacket)
except error as e:
raise error, "Error packing message " +hex(messageID)+"; probably the packet structure is recorded incorrectly in c.getPacketStruct()"
message=pack(c.HEADER_FORMAT_WITH_DATA , messageID , len(dataPacketStr) , destID|0x80 , sourceID) + dataPacketStr
else:
# If no data packet then header consists of concatenation of: messageID (2 bytes),param 1 byte, param2 bytes,destination byte, sourceID byte
message=pack(c.HEADER_FORMAT_WITHOUT_DATA,messageID,param1,param2,destID,sourceID)
if DEBUG_MODE: self.disp(message,"TX: ")
numBytesWritten=self.device.write(message)
def readMessage(self):
""" Read a single message from the device and return tuple of messageID, parameters 1 & 2, destination and sourceID ID, and data packet
(if included), where dataPacket is a tuple of all the message dependent parameters decoded from hex,
as specified in the protocol documentation. Normally the user doesn't need to call this method as it's automatically called by query()"""
# Read 6 byte header from device
headerRaw = self.device.read(c.NUM_HEADER_BYTES)
if headerRaw == "":
raise MessageReceiptError, "Timeout reading from the device"
# Check if a data packet is attached (i.e. get the 5th byte and check if the MSB is set)
isDataPacket = unpack("B", headerRaw[4])[0] >> 7
# Read data packet if it exists, and interpret the message accordingly
if isDataPacket:
header = unpack(c.HEADER_FORMAT_WITH_DATA, headerRaw)
messageID = header[0]
dataPacketLength = header[1]
param1 = None
param2 = None
destID = header[2]
sourceID = header[3]
destID = destID & 0x7F
dataPacketRaw = self.device.read(dataPacketLength)
if DEBUG_MODE: self.disp(headerRaw + dataPacketRaw, "RX: ")
try:
dataPacket = unpack(c.getPacketStruct(messageID),
dataPacketRaw)
except error as e:
# If an error occurs, it's likely due to a problem with the manual inputted data for packet structure in aptconsts
raise
else:
if DEBUG_MODE: self.disp(headerRaw, "RX: ")
header = unpack(c.HEADER_FORMAT_WITHOUT_DATA, headerRaw)
messageID = header[0]
param1 = header[1]
param2 = header[2]
destID = header[3]
sourceID = header[4]
dataPacket = None
# Return tuple containing all the message parameters
return (messageID, param1, param2, destID, sourceID, dataPacket)
def readMessage(self):
""" Read a single message from the device and return tuple of messageID, parameters 1 & 2, destination and sourceID ID, and data packet
(if included), where dataPacket is a tuple of all the message dependent parameters decoded from hex,
as specified in the protocol documentation. Normally the user doesn't need to call this method as it's automatically called by query()"""
# Read 6 byte header from device
headerRaw=self.device.read(c.NUM_HEADER_BYTES)
if headerRaw=="": raise MessageReceiptError, "Timeout reading from the device"
# Check if a data packet is attached (i.e. get the 5th byte and check if the MSB is set)
isDataPacket=unpack("B",headerRaw[4])[0]>>7
# Read data packet if it exists, and interpret the message accordingly
if isDataPacket:
header=unpack(c.HEADER_FORMAT_WITH_DATA,headerRaw)
messageID=header[0]
dataPacketLength=header[1]
param1=None
param2=None
destID=header[2]
sourceID=header[3]
destID=destID&0x7F
dataPacketRaw=self.device.read(dataPacketLength)
if DEBUG_MODE: self.disp(headerRaw+dataPacketRaw,"RX: ")
try:
dataPacket=unpack(c.getPacketStruct(messageID),dataPacketRaw)
except error as e:
# If an error occurs, it's likely due to a problem with the manual inputted data for packet structure in aptconsts
raise
else:
if DEBUG_MODE: self.disp(headerRaw,"RX: ")
header=unpack(c.HEADER_FORMAT_WITHOUT_DATA,headerRaw)
messageID=header[0]
param1=header[1]
param2=header[2]
destID=header[3]
sourceID=header[4]
dataPacket=None
# Return tuple containing all the message parameters
return (messageID,param1,param2,destID,sourceID,dataPacket)
