You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
144 lines
4.1 KiB
144 lines
4.1 KiB
# Implementation of a very simple, custom USB device in Python. The device has an
|
|
# IN and OUT endpoint, accepts up to 64 bytes of data on the OUT endpoint, and echos
|
|
# that data back to the IN endpoint.
|
|
#
|
|
# To run, just execute this file on a device with machine.USBDevice support. The device
|
|
# will then change to the custom USB device.
|
|
#
|
|
# For example, use `mpremote` (the `--no-follow` option starts the script running
|
|
# without waiting for a response, because there won't be a response after the device
|
|
# changes its USB mode):
|
|
#
|
|
# $ mpremote run --no-follow usb_simple_device.py
|
|
#
|
|
# Then, run the host side of the example on your PC using:
|
|
#
|
|
# $ sudo python usb_simple_host_pyusb.py
|
|
#
|
|
# You'll need to have `pyusb` installed via `pip install pyusb` to run the host PC code.
|
|
# And `sudo` is most likely needed to access the custom USB device.
|
|
#
|
|
# Once you have finished running the code, you will need to reset or unplug the USB
|
|
# device to stop it.
|
|
|
|
import machine
|
|
|
|
# VID and PID of the USB device.
|
|
VID = 0xF055
|
|
PID = 0x9999
|
|
|
|
# USB endpoints used by the device.
|
|
EP_OUT = 0x01
|
|
EP_IN = 0x81
|
|
|
|
# USB device descriptor.
|
|
_desc_dev = bytes(
|
|
[
|
|
0x12, # bLength
|
|
0x01, # bDescriptorType: Device
|
|
0x00,
|
|
0x02, # USB version: 2.00
|
|
0xFF, # bDeviceClass: vendor
|
|
0x00, # bDeviceSubClass
|
|
0x01, # bDeviceProtocol
|
|
0x40, # bMaxPacketSize
|
|
VID & 0xFF,
|
|
VID >> 8 & 0xFF, # VID
|
|
PID & 0xFF,
|
|
PID >> 8 & 0xFF, # PID
|
|
0x00,
|
|
0x01, # bcdDevice: 1.00
|
|
0x11, # iManufacturer
|
|
0x12, # iProduct
|
|
0x13, # iSerialNumber
|
|
0x01, # bNumConfigurations: 1
|
|
]
|
|
)
|
|
|
|
# USB configuration descriptor.
|
|
_desc_cfg = bytes(
|
|
[
|
|
# Configuration Descriptor.
|
|
0x09, # bLength
|
|
0x02, # bDescriptorType: configuration
|
|
0x20,
|
|
0x00, # wTotalLength: 32
|
|
0x01, # bNumInterfaces
|
|
0x01, # bConfigurationValue
|
|
0x14, # iConfiguration
|
|
0xA0, # bmAttributes
|
|
0x96, # bMaxPower
|
|
# Interface Descriptor.
|
|
0x09, # bLength
|
|
0x04, # bDescriptorType: interface
|
|
0x00, # bInterfaceNumber
|
|
0x00, # bAlternateSetting
|
|
0x02, # bNumEndpoints
|
|
0xFF, # bInterfaceClass
|
|
0x03, # bInterfaceSubClass
|
|
0x00, # bInterfaceProtocol
|
|
0x15, # iInterface
|
|
# Endpoint IN1.
|
|
0x07, # bLength
|
|
0x05, # bDescriptorType: endpoint
|
|
EP_IN, # bEndpointAddress
|
|
0x03, # bmAttributes: interrupt
|
|
0x40,
|
|
0x00, # wMaxPacketSize
|
|
0x0A, # bInterval
|
|
# Endpoint OUT1.
|
|
0x07, # bLength
|
|
0x05, # bDescriptorType: endpoint
|
|
EP_OUT, # bEndpointAddress
|
|
0x02, # bmAttributes: bulk
|
|
0x40,
|
|
0x00, # wMaxPacketSize
|
|
0x00, # bInterval
|
|
]
|
|
)
|
|
|
|
# USB strings.
|
|
_desc_strs = {
|
|
0x11: b"iManufacturer",
|
|
0x12: b"iProduct",
|
|
0x13: b"iSerial",
|
|
0x14: b"iInterface",
|
|
0x15: b"iInterface",
|
|
0x16: b"Extra information",
|
|
}
|
|
|
|
|
|
# USB callback for when our custom USB interface is opened by the host.
|
|
def _open_itf_cb(interface_desc_view):
|
|
print("_open_itf_cb", bytes(interface_desc_view))
|
|
# Prepare to receive first data packet on the OUT endpoint.
|
|
usbd.submit_xfer(EP_OUT, usbd_buf)
|
|
|
|
|
|
# USB callback for when a data transfer (IN or OUT) has completed.
|
|
def _xfer_cb(ep_addr, result, xferred_bytes):
|
|
print("_xfer_cb", ep_addr, result, xferred_bytes)
|
|
if ep_addr == EP_OUT:
|
|
# Received data packet from the host, print it out.
|
|
print(usbd_buf)
|
|
# And then echo the data back to the host.
|
|
usbd.submit_xfer(EP_IN, memoryview(usbd_buf)[:xferred_bytes])
|
|
elif ep_addr == EP_IN:
|
|
# Host got our data, prepare to receive the next data packet.
|
|
usbd.submit_xfer(EP_OUT, usbd_buf)
|
|
|
|
|
|
# USB data buffer, for IN and OUT transfers.
|
|
usbd_buf = bytearray(64)
|
|
|
|
# Switch the USB device to our custom USB driver.
|
|
usbd = machine.USBDevice()
|
|
usbd.builtin_driver = usbd.BUILTIN_NONE
|
|
usbd.config(
|
|
desc_dev=_desc_dev,
|
|
desc_cfg=_desc_cfg,
|
|
desc_strs=_desc_strs,
|
|
open_itf_cb=_open_itf_cb,
|
|
xfer_cb=_xfer_cb,
|
|
)
|
|
usbd.active(1)
|
|
|