Help with using libusb or vcom to receive bulk data

vxs187 — Thu, 21 Feb 2019 19:14:05 GMT

Hi! I am working on a project that requires bulk data transfer. I was trying to use the given examples to learn how to use the usbd_rom_cdc_vcom and usbd_rom_libusb examples, but am not able to figure out how to read the data that is sent by the host/controller, or how to connect the device to the host. I am just starting with using NXP processors for programming, would be really helpful if someone could assist me with this.

Re: Help with using libusb or vcom to receive bulk data

soledad — Mon, 04 Mar 2019 16:55:10 GMT

Hi,

Is this issue the same than the following thread?

https://community.nxp.com/thread/417095

Regards

Sol

Re: Help with using libusb or vcom to receive bulk data

soledad — Mon, 04 Mar 2019 16:56:42 GMT

Hi,

I suggest to check the following thread

https://community.nxp.com/thread/454107

Regards

Sol

Re: Help with using libusb or vcom to receive bulk data

vxs187 — Mon, 04 Mar 2019 17:01:22 GMT

Does the 4370 have a ROM API?

Re: Help with using libusb or vcom to receive bulk data

vxs187 — Mon, 04 Mar 2019 17:16:27 GMT

I am using this program on the MCU side:

while (1) {
/* wait until host is connected */
while (libusbdev_Connected() == 0) {
/* Sleep until next IRQ happens */
__WFI(); ------------------> This is where the program gets stuck, I don't understand what kind of interrupt it is expecting. I am using pyusb from the host end and it gives the error following this code. soledad
}

while (libusbdev_Connected()) {

if (libusbdev_QueueReadDone() != -1) {

/* Dummy process read data ......*/
/* requeue read request */
libusbdev_QueueReadReq(g_rxBuff, PACKET_BUFFER_SIZE);
}

if (libusbdev_QueueSendDone() == 0) {
/* Queue send request */
libusbdev_QueueSendReq(g_rxBuff, PACKET_BUFFER_SIZE);
}
}
}

HOST SIDE: ON PYTHON (using pyusb)

OUTPUT:

dev1 = usb.core.find(idVendor = 0x1fc9, idProduct = 0x0090)

>>> print(dev1)

OUTPUT:

DEVICE ID 1fc9:0090 on Bus 001 Address 027 =================

bLength : 0x12 (18 bytes)

bDescriptorType : 0x1 Device

bcdUSB : 0x200 USB 2.0

bDeviceClass : 0xef Miscellaneous

bDeviceSubClass : 0x2

bDeviceProtocol : 0x1

bMaxPacketSize0 : 0x40 (64 bytes)

idVendor : 0x1fc9

idProduct : 0x0090

bcdDevice : 0x100 Device 1.0

iManufacturer : 0x1 NXP Semiconductors

iProduct : 0x2 LPC-LINK2 DATA PORT

iSerialNumber : 0x3 I3FWNUOV

bNumConfigurations : 0x1

CONFIGURATION 1: 500 mA ==================================

bLength : 0x9 (9 bytes)

bDescriptorType : 0x2 Configuration

wTotalLength : 0xab (171 bytes)

bNumInterfaces : 0x5

bConfigurationValue : 0x1

iConfiguration : 0x0

bmAttributes : 0x80 Bus Powered

bMaxPower : 0xfa (500 mA)

INTERFACE 0: Human Interface Device ====================

bLength : 0x9 (9 bytes)

bDescriptorType : 0x4 Interface

bInterfaceNumber : 0x0

bAlternateSetting : 0x0

bNumEndpoints : 0x2

bInterfaceClass : 0x3 Human Interface Device

bInterfaceSubClass : 0x0

bInterfaceProtocol : 0x0

iInterface : 0x4 Error Accessing String

ENDPOINT 0x81: Interrupt IN ==========================

bLength : 0x7 (7 bytes)

bDescriptorType : 0x5 Endpoint

bEndpointAddress : 0x81 IN

bmAttributes : 0x3 Interrupt

wMaxPacketSize : 0x400 (1024 bytes)

bInterval : 0x4

ENDPOINT 0x1: Interrupt OUT ==========================

bLength : 0x7 (7 bytes)

bDescriptorType : 0x5 Endpoint

bEndpointAddress : 0x1 OUT

bmAttributes : 0x3 Interrupt

wMaxPacketSize : 0x400 (1024 bytes)

bInterval : 0x4

INTERFACE 4: Human Interface Device ====================

bLength : 0x9 (9 bytes)

bDescriptorType : 0x4 Interface

bInterfaceNumber : 0x4

bAlternateSetting : 0x0

bNumEndpoints : 0x2

bInterfaceClass : 0x3 Human Interface Device

bInterfaceSubClass : 0x0

bInterfaceProtocol : 0x0

iInterface : 0x7 Error Accessing String

ENDPOINT 0x84: Interrupt IN ==========================

bLength : 0x7 (7 bytes)

bDescriptorType : 0x5 Endpoint

bEndpointAddress : 0x84 IN

bmAttributes : 0x3 Interrupt

wMaxPacketSize : 0x400 (1024 bytes)

bInterval : 0x1

ENDPOINT 0x4: Interrupt OUT ==========================

bLength : 0x7 (7 bytes)

bDescriptorType : 0x5 Endpoint

bEndpointAddress : 0x4 OUT

bmAttributes : 0x3 Interrupt

wMaxPacketSize : 0x400 (1024 bytes)

bInterval : 0x1

INTERFACE 1: CDC Communication =========================

bLength : 0x9 (9 bytes)

bDescriptorType : 0x4 Interface

bInterfaceNumber : 0x1

bAlternateSetting : 0x0

bNumEndpoints : 0x1

bInterfaceClass : 0x2 CDC Communication

bInterfaceSubClass : 0x2

bInterfaceProtocol : 0x0

iInterface : 0x5 Error Accessing String

ENDPOINT 0x83: Interrupt IN ==========================

bLength : 0x7 (7 bytes)

bDescriptorType : 0x5 Endpoint

bEndpointAddress : 0x83 IN

bmAttributes : 0x3 Interrupt

wMaxPacketSize : 0x10 (16 bytes)

bInterval : 0x4

INTERFACE 2: CDC Data ==================================

bLength : 0x9 (9 bytes)

bDescriptorType : 0x4 Interface

bInterfaceNumber : 0x2

bAlternateSetting : 0x0

bNumEndpoints : 0x2

bInterfaceClass : 0xa CDC Data

bInterfaceSubClass : 0x0

bInterfaceProtocol : 0x0

iInterface : 0x5 Error Accessing String

ENDPOINT 0x2: Bulk OUT ===============================

bLength : 0x7 (7 bytes)

bDescriptorType : 0x5 Endpoint

bEndpointAddress : 0x2 OUT

bmAttributes : 0x2 Bulk

wMaxPacketSize : 0x200 (512 bytes)

bInterval : 0x0

ENDPOINT 0x82: Bulk IN ===============================

bLength : 0x7 (7 bytes)

bDescriptorType : 0x5 Endpoint

bEndpointAddress : 0x82 IN

bmAttributes : 0x2 Bulk

wMaxPacketSize : 0x200 (512 bytes)

bInterval : 0x0

INTERFACE 3: Human Interface Device ====================

bLength : 0x9 (9 bytes)

bDescriptorType : 0x4 Interface

bInterfaceNumber : 0x3

bAlternateSetting : 0x0

bNumEndpoints : 0x2

bInterfaceClass : 0x3 Human Interface Device

bInterfaceSubClass : 0x0

bInterfaceProtocol : 0x0

iInterface : 0x6 Error Accessing String

ENDPOINT 0x85: Interrupt IN ==========================

bLength : 0x7 (7 bytes)

bDescriptorType : 0x5 Endpoint

bEndpointAddress : 0x85 IN

bmAttributes : 0x3 Interrupt

wMaxPacketSize : 0x40 (64 bytes)

bInterval : 0x2

ENDPOINT 0x5: Interrupt OUT ==========================

bLength : 0x7 (7 bytes)

bDescriptorType : 0x5 Endpoint

bEndpointAddress : 0x5 OUT

bmAttributes : 0x3 Interrupt

wMaxPacketSize : 0x40 (64 bytes)

bInterval : 0x2

>>> cfg =devs.set_configuration() -> Sets the configuration to active mode.

>>> intf = cfg[(0,0)] -> This is the interface, here interface 0.

>>> print(intf)

OUTPUT:

INTERFACE 0: Human Interface Device ====================

bLength : 0x9 (9 bytes)

bDescriptorType : 0x4 Interface

bInterfaceNumber : 0x0

bAlternateSetting : 0x0

bNumEndpoints : 0x2

bInterfaceClass : 0x3 Human Interface Device

bInterfaceSubClass : 0x0

bInterfaceProtocol : 0x0

iInterface : 0x4 Error Accessing String

ENDPOINT 0x81: Interrupt IN ==========================

bLength : 0x7 (7 bytes)

bDescriptorType : 0x5 Endpoint

bEndpointAddress : 0x81 IN

bmAttributes : 0x3 Interrupt

wMaxPacketSize : 0x400 (1024 bytes)

bInterval : 0x4

ENDPOINT 0x1: Interrupt OUT ==========================

bLength : 0x7 (7 bytes)

bDescriptorType : 0x5 Endpoint

bEndpointAddress : 0x1 OUT

bmAttributes : 0x3 Interrupt

wMaxPacketSize : 0x400 (1024 bytes)

bInterval : 0x4

>>> ep = usb.util.find_descriptor( intf, custom_match = lambda e: usb.util.endpoint_direction(e.bEndpointAddress) == usb.util.ENDPOINT_OUT)

>>> print(ep)

ENDPOINT 0x1: Interrupt OUT ==========================

bLength : 0x7 (7 bytes)

bDescriptorType : 0x5 Endpoint

bEndpointAddress : 0x1 OUT

bmAttributes : 0x3 Interrupt

wMaxPacketSize : 0x400 (1024 bytes)

bInterval : 0x4

>>> ep.write('test')

ERROR:

Traceback (most recent call last):

File "<stdin>", line 1, in <module>

File "C:\Users\viswe\AppData\Local\Programs\Python\Python37-32\lib\site-packages\usb\core.py", line 387, in write

return self.device.write(self, data, timeout)

File "C:\Users\viswe\AppData\Local\Programs\Python\Python37-32\lib\site-packages\usb\core.py", line 948, in write

self.__get_timeout(timeout)

File "C:\Users\viswe\AppData\Local\Programs\Python\Python37-32\lib\site-packages\usb\backend\libusb1.py", line 842, in intr_write

timeout)

File "C:\Users\viswe\AppData\Local\Programs\Python\Python37-32\lib\site-packages\usb\backend\libusb1.py", line 920, in __write

_check(retval)

File "C:\Users\viswe\AppData\Local\Programs\Python\Python37-32\lib\site-packages\usb\backend\libusb1.py", line 595, in _check

raise USBError(_strerror(ret), ret, _libusb_errno[ret])

usb.core.USBError: [Errno 5] Input/Output Error

Re: Help with using libusb or vcom to receive bulk data

soledad — Tue, 05 Mar 2019 03:08:03 GMT

Sorry, I didn't see the device you are using. No, The USB ROM API is available on parts LPC4350/30/20 and LPC43S50/S30/S20.

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