cdc_acm problem

[Andrea Gonelli]

hello

using the usbd_ble_uart_pca10056 demo code connected to a microchip USB_CDC pic32 microcontroller I riceve this erroro on debug interface

<info> app: USBD BLE UART example started.
<info> app: USB power detected
<info> app: USB ready
<debug> nrf_ble_gatt: Requesting to update ATT MTU to 64 bytes on connection 0x0.
<info> app: BLE NUS connected
<debug> nrf_ble_gatt: ATT MTU updated to 64 bytes on connection 0x0 (response).
<info> app: Data len is set to 0x3D(61)
<debug> app: ATT MTU exchange completed. central 0xF7 peripheral 0x40
<debug> app: Received data from BLE NUS. Writing data on CDC ACM.
<debug> app: 30 31 32 33 34 35 36 37|01234567
<debug> app: 38 39 30 31 32 33 34 35|89012345
<debug> app: 36 37 38 39 |6789
<info> app: CDC ACM unavailable, data received: 01234567890123456789

NUS seems work fine but I'm not able to understand what is going wrong on usb side

thanks for any suggestion

Andrea Gonelli

[Andrea Gonelli]

Hello,

I'm not an USB specialist, so I need time to understand how could manage everything

anyway

using debug messages on nRF side I found this

come scritto sopra, connecting to microchip I can see

<info> app: CDC ACM unavailable, data received: 01234567890123456789

connecting to my laptop I can see

<info> app: CDC ACM unavailable, data received: 01234567890123456789

running a terminal program and enabling the connection

<debug> app: Received data from BLE NUS. Writing data on CDC ACM.

so, it seems that on PIC32 side there is not an equivalent of com port open

whato do you think about it?

thanks

Andrea Gonelli

[awneil]

How did you confirm that the PIC is actually fully & correctly enumerating the Nordic DK?

Assuming that it is,

Andrea Gonelli said:

it seems that on PIC32 side there is not an equivalent of com port open

seems a reasonable theory.

Andrea Gonelli said:

microchip MC2200 USB CDC module works fine with PIC32

You mean MCP2200: https://www.microchip.com/wwwproducts/en/en546923

Maybe your PIC code is looking for some specific feature(s) of that chip?

Again, you need to instrument the PIC code to see what it is doing - and what is different between the "working" (MCP2200) case, and the DK ...

[Nguyen Hoan Hoang]

It is unlikely that the PIC32 automatically maps the ACM to a COM port.  You most probably need to go low level USB protocol directly.  You need to look at the PIC32 USB stack to see how you can access the ACM on the PC32 side.  You seem to have the PC32 firmware side under control.  So it is a matter of comparing the USB stack response from a working device with the nRF.  A side from that I don't see what else that could help here.