RT1015 USB OTG1 EVK Demo

[variable_andrew]

The evkmimxrt1015_dev_cdc_vcom_lite_bm demo works fine on my EVK, but not on my custom board. 

The custom board is up and running, I2C, GPIO, clocks all working, just seems to be USB not working yet. 

I tested the evkmimxrt1015_dev_cdc_vcom_lite_bm demo on the EVK both as-is, and then after removing Board_InitPins() that seem to only enable UART RX/TX, and updating the memory footprint to avoid external FLASH (all code is in SRAM_OC), as per:

Memory region         Used Size  Region Size  %age Used

         SRAM_OC:       38904 B        64 KB     59.36%

        SRAM_DTC:          0 GB        32 KB      0.00%

        SRAM_ITC:          0 GB        32 KB      0.00%

Finished building target: evkmimxrt1015_dev_cdc_vcom_lite_bm.axf

After confirming the stripped down demo worked on the EVK - I tested on my board assuming the only connection I need should be the USB OTG pins. 

In the custom board - if I have D+, D-, and USB_OTG1_VBUS (via a small cap) connected to the usb connector on the board - any idea of what else should be needed for the custom board to copy the EVK for the USB OTG demo?

Although the USB_OTG_ID pin is connected on the EVK, the evkmimxrt1015_dev_cdc_vcom_lite_bm doesn't seem to enable this pin in the IO_MUX - so I assume I don't need this pin wired at all. 

[ETCTim]

Did you ever get this problem solved? I have a similar issue. I have noticed that if use ITC, my USB works fine, but it doesn't work when using OC. I noticed above that you are using OC.

Tim

[variable_andrew]

Hi ETCTim , 

Yes, our problem ended up being that we needed the inductor (L4 in the rt1015evk schematics). 

WRT to ITC vs OC, there's a different post on that one. 

Loading all code to OC will mean you'll have issues w/ breakpoints running as default. 

The other problem w/ SRAM_OC .. MIGHT be due to caching - the core misses updates from the peripheral, so you need to move some buffers... maybe?

(edit - but based on the above - running from SRAM_OC worked out of the box - so long as I wasn't using breakpoints). 

 
There is another post specifically related to buffers / caching / updating the core - but I'm having trouble finding the explanation about this, so I don't remember what you need to move - but for moving buffers if you need to do that, see here: Placing data into different RAM blocks 

[jeremyzhou]

Hi variable_andrew,

Thank you for your interest in NXP Semiconductor products and for the opportunity to serve you.
I'd like to know more information about the phenomenon, so I was wondering if you can share the schematic about the USB port of your custom board, in addition, I've attached a tool which can demonstrate the information about the USB enumeration process, maybe you can do a test with it and show me result.

Have a great day,
TIC

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[variable_andrew]

Hi jeremyzhou‌ , 

Thanks for the response - 

I'm running on MacOS here - which has a similar tool built in - so when running the demo on the EVK, the output looks like this:

But when I run on the custom board - it doesn't enumerate. 

(I connect the LPC-LINK2 JTAG to the custom board instead of the EVK and run the demo, and then the MCU VIRTUAL COM DEMO doesn't show up)

The schematic looks like this for USB (the connector is this (link) USB 2.0 Type-C connector) :

And connections to the iMX RT:

[variable_andrew]

We just tested wiring up the 0 ohm resistors R61 and R63 (to short out the inductor L4) on the EVK - and now the EVK behaves like our board where the VCOM demo doesn't work.

So it appears that the L4 inductor is very crucial to USB on the RT parts?

If so - we'll add something like L4 to our design. 

[jeremyzhou]

Hi variable_andrew,

Thanks for your reply.
According to reply, I think the issue definitely relate to the hardware, I'd highly recommend you to modify the USB port design by referring to the attachment.

Have a great day,
TIC

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Note:
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- We are following threads for 7 weeks after the last post, later replies are ignored
Please open a new thread and refer to the closed one, if you have a related question at a later point in time.
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[variable_andrew]

Will give it a shot, thanks!