Raphaël,
To convert numerical values to byte strings, and vice versa, please use
the struct API :
import struct
s = struct.pack("<BL", 0, 5)
v1, v2 = struct.unpack("<BL", s)
Please see the struct help for further details.
Nicolas
Le 21/11/2019 à 12:00, raphael moreau a écrit :
Bonjour,
Thank you for your answer,
The DP5_Programmer's guide can be found here:
http://experimentationlab.berkeley.edu/sites/default/files/images/DP5_Programmers_Guide_A4.pdf
And the entire code is here (Python_SDK\pyDppUSB):
https://www.amptek.com/-/media/ametekamptek/documents/softwares/Python_SDK.zip?la=en
I run the pyDP5.py module (Python_SDK\pyDppUSB\pyDP5.py), and here is
a selected part (from Python_SDK\pyDppUSB\DppLibusb.py) that I'm
interested in. As I said, this code was provide by Amptek when I
contacted them, but it's for demo only in python 2, and not offically
supported (that's the reason why it's pretty "dirty", with the few
correction I already added):
from vbfunctions import *
from vbclasses import *
import usb
import sys
import time
from dppStatus import *
import codecs
decode_hex = codecs.getdecoder("hex_codec")
LIBUSB_TIMEOUT = 500
#REQUEST_STATUS_PACKET =
decode_hex('F5FA01010000FE0F') # Request Status Packet
REQUEST_STATUS_PACKET = '\xf5\xfa\x01\x01\x00\x00\xfe\x0f'
#-------------------------------------------------------------------------------
# DppLibusb Class
#-------------------------------------------------------------------------------
class DppLibusb():
def __init__(self):
self.VENDOR = 0x10C4
self.PRODUCT = 0x842A
self.CONFIGURATION = 1
self.INTERFACE = 0
self.ENDPOINT_IN = 0x81
self.ENDPOINT_OUT = 0x02
self.device = None
self.handle = None
self.device = usb.core.find(idVendor=0x10c4, idProduct=0x842a)
#for bus in usb.busses():
# for dev in bus.devices:
# if dev.idVendor == self.VENDOR and dev.idProduct ==
self.PRODUCT:
# self.device = dev
self.strStatus = str()
self.bArrStatusIn = bytes()
self.bArrBuffer = bytes()
self.AckPid2 = bytes()
self.AckMsg = str()
#self.STATUS = STATUS
self.DataRaw = bytes()
self.Channels = int()
self.Data = int()
self.Header = bytes()
self.bArrArrBuffer = bytearray()
if self.open() == None:
print (sys.stderr, "Unable to open DppLibusb device!")
sys.exit()
return None
def isConnected(self):
_ret = False
iNumBytes = 0
print("Get Status")
*try:*
* iNumBytes = self.write(REQUEST_STATUS_PACKET,
LIBUSB_TIMEOUT)*
**
* except usb.USBError as err:*
* pass*
* if iNumBytes > 0:*
* print ('Bytes Out =',iNumBytes) # debug*
* try:*
**
* self.bArrArrBuffer = self.read(128, LIBUSB_TIMEOUT)*
* self.bArrStatusIn = bytearray(self.bArrArrBuffer)*
**
* except usb.USBError as err:*
* pass*
if len(self.bArrStatusIn) > 0:
print ("STATUS.RAW type ", type(self.STATUS.RAW))
self.STATUS.RAW = bytearray(self.bArrStatusIn[6:70])
if len(self.STATUS.RAW) > 0:
Process_Status(self.STATUS)
if (self.STATUS.SerialNumber > 0):
_ret = True
return _ret
While the iNumbytes get a value from the *iNumBytes =
self.write(REQUEST_STATUS_PACKET, LIBUSB_TIMEOUT)* (which might be a
wrong value), the *self.bArrArrBuffer = self.read(128,
LIBUSB_TIMEOUT)* is never reached. So my guess is that the
REQUEST_STATUS_PACKET is in the wrong format, thus my original
question : how do I write and read instruction in hexadecimal ? Is
converting the whole instruction in string via REQUEST_STATUS_PACKET =
'\xf5\xfa\x01\x01\x00\x00\xfe\x0f' correct ? (I doubt it is). Again,
sorry for the "messy" code, and thanks for any answer provided.
Best regards
Raphaël
> Message du 21/11/19 10:11
> De : "Nicolas Pinault via pyusb-users"
<pyusb-users@lists.sourceforge.net>
> A : pyusb-users@lists.sourceforge.net
> Copie à : "Nicolas Pinault" <nicol...@aaton.com>
> Objet : Re: [pyusb-users] Writing and reading hexadecimal command
>
>
Bonjour Raphaël,
>
> You do not provide enought information.
> Can you provide a link to the DP5 documentation ?
> Can you provide a small code sample ?
>
> Bonne journée,
> Nicolas
>
>
> Le 21/11/2019 à 09:43, raphael moreau a écrit :
>
> Good morning pyusb users,
>
> I'm writing you this emial because I'm facing an issue that
I did not succed to resolve until now, and I'm sure you will.
>
> I'm currently working on a Python project which involve the
communication witn an USB Device (DP5 Amptek SDD Detector, an
x-ray detector), and after a few test it seems that my device
dont understand what I'm telling him to do.
>
> I started with the basic, a Device Status request, which is
the following (.jgp screenshot, I hope you'll be able to see it):
>
>
> I tried the classic dev.write(x,test,x), with test =
'\xf5\xfa\x01\x01\x00\x00\xfe\x0f', or test =
'\xf5\xfa1100\xfe\x0f' but the expected result, which is the
following(same here, .jpg screenshot):
>
>
> does not seems to be return with res = dev.read(x, length,
x) with length = 128 or length = 64 (seems odd to me for the
128 but i guess it's for the array format?)
>
>
> My question is therefore quit simple, how do I pass and read
thoses command ?
>
> I'm using python 3, and I have no problem in term of
identification of the device, configuration, interface and
endpoint IN and OUT, with pyusb.
>
> The program I'm using is an old python 2 demo supplied by
the manufacturer which is not supported by them.
> I precise that I'm rather new to USB and programming in
general, so I apologize if this question seems basic, or had
already been answered to.
>
> Thank you for any response,
>
> Best regards,
>
>
>
> Raphaël Moreau
>
>
>
>
>
>
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