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Modify usb cdc acm device example for multiple ACM devices

Sujan Nag1
Prodigy 190 points

Hello All,

I am working on ti starterkit, and starterware version: AM335X_StarterWare_02_00_01_01

OS: ubuntu 14.04, kernel version 3.13.0-24-generic.

I was playing around with the usb_dev_serial example. By default the example after execution creates a single ttyACM0 entry in linux. We have a requirement to create multiple ACM devices in linux. 

For example after execution of the code, devices like ACM0 and ACM1 should be created.

I did change the driver a bit, changed the descriptors in usbdcdc.c file(attached), but I am not able to create two devices, /dev/ttyACM*

First of all, is it possible to create multiple devices in this version of starterware? If yes than can anyone please guide me to as what I am missing?

4745.usbdcdc.c

Thanks and Regards

Sujan

  • 0
    Prodigy 190 points

    Hello,

    One more point I failed to mention, after execution of the above code, I can check the descriptors in my PC using lsusb -v command. I am able to see the descriptors as expected, but no entry in /dev/

    Here are the descriptors:

    Bus 002 Device 008: ID 1cbe:0002 Luminary Micro Inc.


    Couldn't open device, some information will be missing
    Device Descriptor:
    bLength 18
    bDescriptorType 1
    bcdUSB 2.00
    bDeviceClass 2 Communications
    bDeviceSubClass 0
    bDeviceProtocol 0
    bMaxPacketSize0 64
    idVendor 0x1cbe Luminary Micro Inc.
    idProduct 0x0002
    bcdDevice 1.00
    iManufacturer 1
    iProduct 2
    iSerial 3
    bNumConfigurations 1


    Configuration Descriptor:
    bLength 9
    bDescriptorType 2
    wTotalLength 125
    bNumInterfaces 4
    bConfigurationValue 1
    iConfiguration 5
    bmAttributes 0xc0
    Self Powered
    MaxPower 250mA
    Interface Descriptor:
    bLength 9
    bDescriptorType 4
    bInterfaceNumber 0
    bAlternateSetting 0
    bNumEndpoints 1
    bInterfaceClass 2 Communications
    bInterfaceSubClass 2 Abstract (modem)
    bInterfaceProtocol 1 AT-commands (v.25ter)
    iInterface 4
    CDC Header:
    bcdCDC 1.10
    CDC ACM:
    bmCapabilities 0x06
    sends break
    line coding and serial state
    CDC Union:
    bMasterInterface 0
    bSlaveInterface 1
    CDC Call Management:
    bmCapabilities 0x01
    call management
    bDataInterface 1
    Endpoint Descriptor:
    bLength 7
    bDescriptorType 5
    bEndpointAddress 0x81 EP 1 IN
    bmAttributes 3
    Transfer Type Interrupt
    Synch Type None
    Usage Type Data
    wMaxPacketSize 0x0010 1x 16 bytes
    bInterval 10
    Interface Descriptor:
    bLength 9
    bDescriptorType 4
    bInterfaceNumber 1
    bAlternateSetting 0
    bNumEndpoints 2
    bInterfaceClass 10 CDC Data
    bInterfaceSubClass 0 Unused
    bInterfaceProtocol 0
    iInterface 0
    Endpoint Descriptor:
    bLength 7
    bDescriptorType 5
    bEndpointAddress 0x82 EP 2 IN
    bmAttributes 2
    Transfer Type Bulk
    Synch Type None
    Usage Type Data
    wMaxPacketSize 0x0100 1x 256 bytes
    bInterval 0
    Endpoint Descriptor:
    bLength 7
    bDescriptorType 5
    bEndpointAddress 0x02 EP 2 OUT
    bmAttributes 2
    Transfer Type Bulk
    Synch Type None
    Usage Type Data
    wMaxPacketSize 0x0100 1x 256 bytes
    bInterval 0
    Interface Descriptor:
    bLength 9
    bDescriptorType 4
    bInterfaceNumber 0
    bAlternateSetting 0
    bNumEndpoints 1
    bInterfaceClass 2 Communications
    bInterfaceSubClass 2 Abstract (modem)
    bInterfaceProtocol 1 AT-commands (v.25ter)
    iInterface 4
    CDC Header:
    bcdCDC 1.10
    CDC ACM:
    bmCapabilities 0x06
    sends break
    line coding and serial state
    CDC Union:
    bMasterInterface 0
    bSlaveInterface 1
    CDC Call Management:
    bmCapabilities 0x01
    call management
    bDataInterface 1
    Endpoint Descriptor:
    bLength 7
    bDescriptorType 5
    bEndpointAddress 0x83 EP 3 IN
    bmAttributes 3
    Transfer Type Interrupt
    Synch Type None
    Usage Type Data
    wMaxPacketSize 0x0010 1x 16 bytes
    bInterval 10
    Interface Descriptor:
    bLength 9
    bDescriptorType 4
    bInterfaceNumber 1
    bAlternateSetting 0
    bNumEndpoints 2
    bInterfaceClass 10 CDC Data
    bInterfaceSubClass 0 Unused
    bInterfaceProtocol 0
    iInterface 0
    Endpoint Descriptor:
    bLength 7
    bDescriptorType 5
    bEndpointAddress 0x84 EP 4 IN
    bmAttributes 2
    Transfer Type Bulk
    Synch Type None
    Usage Type Data
    wMaxPacketSize 0x0100 1x 256 bytes
    bInterval 0
    Endpoint Descriptor:
    bLength 7
    bDescriptorType 5
    bEndpointAddress 0x04 EP 4 OUT
    bmAttributes 2
    Transfer Type Bulk
    Synch Type None
    Usage Type Data
    wMaxPacketSize 0x0100 1x 256 bytes
    bInterval 0