how to read data by using pywinusb in python

Question

I can't read hid data by using pywinusb in python.

I referred to this page( https://www.reddit.com/r/learnpython/comments/3z346p/reading_a_usb_data_stream_on_windows/ )

and I have question.

def sample_handler(data): print("Raw data: {0}".format(data))

sample_handler function needs to data.

but

device.set_raw_data_handler(sample_handler)

this code do not give data to sample_handler. is it not error?

and below is my code. my code don't catch read_handler function. how can i fix it. could you help me?

from pywinusb import hid
import time

class PIC18f:
    def __init__(self, VID = 0x04D8, PID=0x003f):

        filter = hid.HidDeviceFilter(vender_id = VID, product_id = PID)
        self.devices = filter.get_devices()
        self.device = self.devices[0]
        self.device.open()


    def write(self, args):

        out_report = self.device.find_output_reports()
        out_report[0].set_raw_data(args)
        out_report[0].send()
        time.sleep(1)

    def read_handler(self, data):
        print("Raw data: {0}".format(data))
        print("done")

    def I2C_Init(self):

        buf = [0x00]
        buf = buf + [0 for i in range(65-len(buf))]

        buf[1] = 0xF1
        buf[2] = 0x1D
        self.write(buf)
        self.device.set_raw_data_handler(read_handler)

test = PIC18f()
test.I2C_Init()

this is error.

Traceback (most recent call last): File "d:/1. Siliconmitus/python/test2.py", line 35, in test.I2C_Init() File "d:/1. Siliconmitus/python/test2.py", line 32, in I2C_Init self.device.set_raw_data_handler(read_handler) NameError: name 'read_handler' is not defined

Answer 1

1. read_handler is not defined because the "read_handler" should be defined inside I2C_Init.

2. The following is an example:

from pywinusb import hid
filter = hid.HidDeviceFilter(vendor_id = 0x0001, product_id = 0x0002)
devices = filter.get_devices()

device = devices[0]

def readData(data): 
    print(data) 
    return None 
    
device.set_raw_data_handler(readData) 
device.open()