import numpy
import itertools
from collections import namedtuple
from ..conversion import dxl_code, dxl_decode
name = 'v2'
DxlBroadcast = 254
[docs]class DxlInstruction(object):
PING = 0x01
READ_DATA = 0x02
WRITE_DATA = 0x03
RESET = 0x06
SYNC_READ = 0x82
SYNC_WRITE = 0x83
# MARK: - Packet Header
# MARK: - Instruction Packet
[docs]class DxlInstructionPacket(namedtuple('DxlInstructionPacket',
('id', 'instruction', 'parameters'))):
""" This class is used to represent a dynamixel instruction packet.
An instruction packet is constructed as follows:
[0xFF, 0xFF, 0xFD, 0x00, ID, LEN_L, LEN_H, INST, PARAM 1, PARAM 2, ..., PARAM N, CRC_L, CRC_H]
(for more details see http://support.robotis.com/en/product/dxl_main.htm)
"""
def _buff(self):
return bytearray(itertools.chain(DxlPacketHeader.marker,
(self.id, ),
dxl_code(self.length, 2),
(self.instruction, ),
self.parameters))
[docs] def to_array(self):
return self._buff() + bytearray(dxl_code(self.checksum, 2))
[docs] def to_string(self):
return bytes(self.to_array())
@property
def length(self):
return len(self.parameters) + 3
@property
def checksum(self):
return crc16(self._buff(), 5 + self.length)
[docs]class DxlPingPacket(DxlInstructionPacket):
""" This class is used to represent ping packet. """
def __new__(cls, id):
return DxlInstructionPacket.__new__(cls, id, DxlInstruction.PING, ())
def __repr__(self):
return 'DxlPingPacket(id={})'.format(self.id)
[docs]class DxlResetPacket(DxlInstructionPacket):
""" This class is used to represent factory reset packet. """
def __new__(cls, id, mode):
return DxlInstructionPacket.__new__(cls, id,
DxlInstruction.RESET, (mode, ))
[docs]class DxlReadDataPacket(DxlInstructionPacket):
""" This class is used to represent read data packet (to read value). """
def __new__(cls, id, address, length):
return DxlInstructionPacket.__new__(cls, id,
DxlInstruction.READ_DATA,
list(dxl_code(address, 2)) +
list(dxl_code(length, 2)))
def __repr__(self):
return 'DxlReadDataPacket(id={}, address={}, length={})'.format(
self.id,
dxl_decode(list(reversed(self.parameters[0:2]))),
dxl_decode(list(reversed(self.parameters[2:4]))))
[docs]class DxlSyncReadPacket(DxlInstructionPacket):
""" This class is used to represent sync read packet (to synchronously read values). """
def __new__(cls, ids, address, length):
return DxlInstructionPacket.__new__(cls, DxlBroadcast,
DxlInstruction.SYNC_READ,
list(dxl_code(address, 2)) +
list(dxl_code(length, 2)) +
list(ids))
def __repr__(self):
return ('DxlSyncReadDataPacket(ids={}, '
'address={}, length={})'.format(self.parameters[4:],
dxl_decode(self.parameters[0:2]),
dxl_decode(self.parameters[2:4])))
[docs]class DxlWriteDataPacket(DxlInstructionPacket):
""" This class is used to reprensent write data packet (to write value). """
def __new__(cls, id, address, coded_value):
return DxlInstructionPacket.__new__(cls, id,
DxlInstruction.WRITE_DATA,
list(dxl_code(address, 2)) +
list(coded_value))
def __repr__(self):
return ('DxlWriteDataPacket(id={}, address={}, value={})'.format(
self.id,
dxl_decode(self.parameters[0:2]),
tuple(self.parameters[2:])))
[docs]class DxlSyncWritePacket(DxlInstructionPacket):
""" This class is used to represent sync write packet (to synchronously write values). """
def __new__(cls, address, length, id_value_couples):
return DxlInstructionPacket.__new__(cls, DxlBroadcast,
DxlInstruction.SYNC_WRITE,
list(itertools.chain(dxl_code(address, 2),
dxl_code(length, 2),
id_value_couples)))
def __repr__(self):
address = dxl_decode(self.parameters[0:2])
length = dxl_decode(self.parameters[2:4])
a = numpy.array(self.parameters[4:]).reshape((-1, length + 1))
ids = a[:, 0]
values = [tuple(v) for v in a[:, 1:]]
return ('DxlSyncWriteDataPacket(ids={}, '
'address={}, length={}, values={})'.format(ids,
address,
length,
values))
# MARK: - Status Packet
[docs]class DxlStatusPacket(namedtuple('DxlStatusPacket', ('id', 'error', 'parameters'))):
""" This class is used to represent a dynamixel status packet.
A status packet is constructed as follows:
[0xFF, 0xFF, 0xFD, 0x00, ID, LEN_L, LEN_H, 0x55, ERROR, PARAM 1, PARAM 2, ..., PARAM N, CRC_L, CRC_H]
(for more details see http://support.robotis.com/en/product/dxl_main.htm)
"""
[docs] @classmethod
def from_string(cls, data):
packet = bytearray(data)
header = DxlPacketHeader.from_string(packet[:DxlPacketHeader.length])
if (len(packet) != DxlPacketHeader.length + header.packet_length or
cls._checksum(packet) != packet[-2:]):
raise ValueError('try to parse corrupted data ({})'.format(packet))
return cls(header.id, packet[8], tuple(packet[9:-2]))
@classmethod
def _checksum(cls, packet):
return bytearray(dxl_code(crc16(packet[:-2], len(packet) - 2), 2))
[docs]def crc16(data_blk, data_blk_size, crc_accum=0):
for j in range(data_blk_size):
i = ((crc_accum >> 8) ^ data_blk[j]) & 0xFF
crc_accum = ((crc_accum << 8) ^ crc_table[i]) % (2 ** 16)
return crc_accum
crc_table = [
0x0000, 0x8005, 0x800F, 0x000A, 0x801B, 0x001E, 0x0014, 0x8011,
0x8033, 0x0036, 0x003C, 0x8039, 0x0028, 0x802D, 0x8027, 0x0022,
0x8063, 0x0066, 0x006C, 0x8069, 0x0078, 0x807D, 0x8077, 0x0072,
0x0050, 0x8055, 0x805F, 0x005A, 0x804B, 0x004E, 0x0044, 0x8041,
0x80C3, 0x00C6, 0x00CC, 0x80C9, 0x00D8, 0x80DD, 0x80D7, 0x00D2,
0x00F0, 0x80F5, 0x80FF, 0x00FA, 0x80EB, 0x00EE, 0x00E4, 0x80E1,
0x00A0, 0x80A5, 0x80AF, 0x00AA, 0x80BB, 0x00BE, 0x00B4, 0x80B1,
0x8093, 0x0096, 0x009C, 0x8099, 0x0088, 0x808D, 0x8087, 0x0082,
0x8183, 0x0186, 0x018C, 0x8189, 0x0198, 0x819D, 0x8197, 0x0192,
0x01B0, 0x81B5, 0x81BF, 0x01BA, 0x81AB, 0x01AE, 0x01A4, 0x81A1,
0x01E0, 0x81E5, 0x81EF, 0x01EA, 0x81FB, 0x01FE, 0x01F4, 0x81F1,
0x81D3, 0x01D6, 0x01DC, 0x81D9, 0x01C8, 0x81CD, 0x81C7, 0x01C2,
0x0140, 0x8145, 0x814F, 0x014A, 0x815B, 0x015E, 0x0154, 0x8151,
0x8173, 0x0176, 0x017C, 0x8179, 0x0168, 0x816D, 0x8167, 0x0162,
0x8123, 0x0126, 0x012C, 0x8129, 0x0138, 0x813D, 0x8137, 0x0132,
0x0110, 0x8115, 0x811F, 0x011A, 0x810B, 0x010E, 0x0104, 0x8101,
0x8303, 0x0306, 0x030C, 0x8309, 0x0318, 0x831D, 0x8317, 0x0312,
0x0330, 0x8335, 0x833F, 0x033A, 0x832B, 0x032E, 0x0324, 0x8321,
0x0360, 0x8365, 0x836F, 0x036A, 0x837B, 0x037E, 0x0374, 0x8371,
0x8353, 0x0356, 0x035C, 0x8359, 0x0348, 0x834D, 0x8347, 0x0342,
0x03C0, 0x83C5, 0x83CF, 0x03CA, 0x83DB, 0x03DE, 0x03D4, 0x83D1,
0x83F3, 0x03F6, 0x03FC, 0x83F9, 0x03E8, 0x83ED, 0x83E7, 0x03E2,
0x83A3, 0x03A6, 0x03AC, 0x83A9, 0x03B8, 0x83BD, 0x83B7, 0x03B2,
0x0390, 0x8395, 0x839F, 0x039A, 0x838B, 0x038E, 0x0384, 0x8381,
0x0280, 0x8285, 0x828F, 0x028A, 0x829B, 0x029E, 0x0294, 0x8291,
0x82B3, 0x02B6, 0x02BC, 0x82B9, 0x02A8, 0x82AD, 0x82A7, 0x02A2,
0x82E3, 0x02E6, 0x02EC, 0x82E9, 0x02F8, 0x82FD, 0x82F7, 0x02F2,
0x02D0, 0x82D5, 0x82DF, 0x02DA, 0x82CB, 0x02CE, 0x02C4, 0x82C1,
0x8243, 0x0246, 0x024C, 0x8249, 0x0258, 0x825D, 0x8257, 0x0252,
0x0270, 0x8275, 0x827F, 0x027A, 0x826B, 0x026E, 0x0264, 0x8261,
0x0220, 0x8225, 0x822F, 0x022A, 0x823B, 0x023E, 0x0234, 0x8231,
0x8213, 0x0216, 0x021C, 0x8219, 0x0208, 0x820D, 0x8207, 0x0202
]
