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SAMA5D27C-LD1G custom board - USB not working

Posted: Wed Jan 20, 2021 4:19 am
by adamfeuer
Hi, I have a SAMA5D27C-LD1G custom board. It boots using AT91Bootstrap, U-Boot, and NuttX RTOS. SDMMC works, serial console works, PIO works. USB Port A does not work (this is the only connected USB port). Both U-Boot and NuttX can turn on the USB and report no devices on the bus, the light on my USB hub port will not illuminate, and the lsusb under Linux on the host does not show the device. I reviewed the circuit schematic and the USBPA and the HHSDPA and HHSDMA traces are connected to the right pads on the SAMA5 chip and the right pins on the connector. I can boot NuttX on the SAMA5D2-XULT and it does show the USB device connected under linux via lsusb.

I'm wondering how to troubleshoot this. Could I have configured AT91Bootstrap wrong? Are there options that would disable USB? I'm basing my config on the sama5d2_lpddr2sip_vb defconfig.

I would paste my config, but the forum software classifies it as spam.

Re: SAMA5D27C-LD1G custom board - USB not working

Posted: Thu Jan 21, 2021 4:57 am
by adamfeuer
Solved the problem. It was a mistake in my circuit schematic. I did not have GNDUTMII connected to GND. So the USB UTMI transceiver was not powered up. I greenwired a connection (soldering under a microscope) and after that, everything works perfectly– I have ethernet over USB working via a CDC/ECM driver on NuttX.