1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
|
"""
Enable basic can over a PCAN USB device.
"""
import logging
import sys
logger = logging.getLogger(__name__)
from can.interfaces.PCANBasic import *
from can.bus import BusABC
from can.message import Message
from can import CanError
import time
boottimeEpoch = 0
try:
import uptime
import datetime
boottimeEpoch = (uptime.boottime() - datetime.datetime.utcfromtimestamp(0)).total_seconds()
except:
boottimeEpoch = 0
if sys.version_info >= (3, 3):
# new in 3.3
timeout_clock = time.perf_counter
else:
# deprecated in 3.3
timeout_clock = time.clock
# Set up logging
logging.basicConfig(level=logging.WARNING)
log = logging.getLogger('can.pcan')
pcan_bitrate_objs = {1000000 : PCAN_BAUD_1M,
800000 : PCAN_BAUD_800K,
500000 : PCAN_BAUD_500K,
250000 : PCAN_BAUD_250K,
125000 : PCAN_BAUD_125K,
100000 : PCAN_BAUD_100K,
95000 : PCAN_BAUD_95K,
83000 : PCAN_BAUD_83K,
50000 : PCAN_BAUD_50K,
47000 : PCAN_BAUD_47K,
33000 : PCAN_BAUD_33K,
20000 : PCAN_BAUD_20K,
10000 : PCAN_BAUD_10K,
5000 : PCAN_BAUD_5K}
class PcanBus(BusABC):
def __init__(self, channel, *args, **kwargs):
"""A PCAN USB interface to CAN.
On top of the usual :class:`~can.Bus` methods provided,
the PCAN interface includes the `flash()` and `status()` methods.
:param str channel:
The can interface name. An example would be PCAN_USBBUS1
:param int bitrate:
Bitrate of channel in bit/s.
Default is 500 Kbs
"""
if channel is None or channel == '':
raise ArgumentError("Must specify a PCAN channel")
else:
self.channel_info = channel
bitrate = kwargs.get('bitrate', 500000)
pcan_bitrate = pcan_bitrate_objs.get(bitrate, PCAN_BAUD_500K)
hwtype = PCAN_TYPE_ISA
ioport = 0x02A0
interrupt = 11
self.m_objPCANBasic = PCANBasic()
self.m_PcanHandle = globals()[channel]
result = self.m_objPCANBasic.Initialize(self.m_PcanHandle, pcan_bitrate, hwtype, ioport, interrupt)
if result != PCAN_ERROR_OK:
raise PcanError(self._get_formatted_error(result))
super(PcanBus, self).__init__(*args, **kwargs)
def _get_formatted_error(self, error):
"""
Gets the text using the GetErrorText API function
If the function succeeds, the translated error is returned. If it fails,
a text describing the current error is returned. Multiple errors may
be present in which case their individual messages are included in the
return string, one line per error.
"""
def bits(n):
while n:
b = n & (~n+1)
yield b
n ^= b
stsReturn = self.m_objPCANBasic.GetErrorText(error, 0)
if stsReturn[0] != PCAN_ERROR_OK:
strings = []
for b in bits(error):
stsReturn = self.m_objPCANBasic.GetErrorText(b, 0)
if stsReturn[0] != PCAN_ERROR_OK:
text = "An error occurred. Error-code's text ({0:X}h) couldn't be retrieved".format(error)
else:
text = stsReturn[1].decode('utf-8')
strings.append(text)
complete_text = '\n'.join(strings)
else:
complete_text = stsReturn[1].decode('utf-8')
return complete_text
def status(self):
"""
Query the PCAN bus status.
:return: The status code. See values in pcan_constants.py
"""
return self.m_objPCANBasic.GetStatus(self.channel_info)
def status_is_ok(self):
"""
Convenience method to check that the bus status is OK
"""
status = self.status()
return status == PCAN_ERROR_OK
def reset(self):
# Command the PCAN driver to reset the bus after an error.
status = self.m_objPCANBasic.Reset(self.channel_info)
return status == PCAN_ERROR_OK
def recv(self, timeout=None):
start_time = timeout_clock()
if timeout is None:
timeout = 0
rx_msg = Message()
log.debug("Trying to read a msg")
result = None
while result is None:
result = self.m_objPCANBasic.Read(self.m_PcanHandle)
if result[0] == PCAN_ERROR_QRCVEMPTY or result[0] == PCAN_ERROR_BUSLIGHT or result[0] == PCAN_ERROR_BUSHEAVY:
if timeout_clock() - start_time >= timeout:
return None
else:
result = None
time.sleep(0.001)
elif result[0] != PCAN_ERROR_OK:
raise PcanError(self._get_formatted_error(result[0]))
theMsg = result[1]
itsTimeStamp = result[2]
log.debug("Received a message")
bIsRTR = (theMsg.MSGTYPE & PCAN_MESSAGE_RTR.value) == PCAN_MESSAGE_RTR.value
bIsExt = (theMsg.MSGTYPE & PCAN_MESSAGE_EXTENDED.value) == PCAN_MESSAGE_EXTENDED.value
if bIsExt:
#rx_msg.id_type = ID_TYPE_EXTENDED
log.debug("CAN: Extended")
else:
#rx_msg.id_type = ID_TYPE_STANDARD
log.debug("CAN: Standard")
dlc = theMsg.LEN
timestamp = boottimeEpoch + ((itsTimeStamp.micros + (1000 * itsTimeStamp.millis)) / (1000.0 * 1000.0))
rx_msg = Message(timestamp=timestamp,
arbitration_id=theMsg.ID,
extended_id=bIsExt,
is_remote_frame=bIsRTR,
dlc=dlc,
data=theMsg.DATA[:dlc])
return rx_msg
def send(self, msg):
if msg.id_type:
msgType = PCAN_MESSAGE_EXTENDED
else:
msgType = PCAN_MESSAGE_STANDARD
# create a TPCANMsg message structure
CANMsg = TPCANMsg()
# configure the message. ID, Length of data, message type and data
CANMsg.ID = msg.arbitration_id
CANMsg.LEN = len(msg.data)
CANMsg.MSGTYPE = msgType
# if a remote frame will be sent, data bytes are not important.
if msg.is_remote_frame:
CANMsg.MSGTYPE = msgType.value | PCAN_MESSAGE_RTR.value
else:
# copy data
for i in range(CANMsg.LEN):
CANMsg.DATA[i] = msg.data[i]
log.debug("Data: %s", msg.data)
log.debug("Type: %s", type(msg.data))
result = self.m_objPCANBasic.Write(self.m_PcanHandle, CANMsg)
if result != PCAN_ERROR_OK:
raise PcanError("Failed to send: " + self._get_formatted_error(result))
def flash(self, flash):
"""
Turn on or off flashing of the device's LED for physical
identification purposes.
"""
self.m_objPCANBasic.SetValue(self.channel_info, PCAN_CHANNEL_IDENTIFYING, bool(flash))
def shutdown(self):
self.m_objPCANBasic.Uninitialize(self.m_PcanHandle)
class PcanError(CanError):
pass
|
