Meanwhile I've tried to port the USB stack I used for atusb (which in turn is derived from the stack in idbg) to the Kinetis series. It still stubbornly refuses to work, but I think I can't be far from success. Just have to find that silly mistake ...
I've been able to verify that the hardware is fine by running the stack from https://github.com/payne92/bare-metal-arm which cheerfully announces itself as Bus 001 Device 036: ID dead:beaf As the "real" ID, I've tentatively assigned the USB PID 0xae70 (that's "AnELok, device 0"): http://en.qi-hardware.com/wiki/USB_product_ID_assignments Speaking of hardware, there two issues with the current design: 1) it's missing the 33 R series resistors on D+/D-. I found out about them only after discovering the "Kinetis L Peripheral Module Quick Reference" [1], which is the document that made off with all the useful details you'd hope to find in the reference manual, but won't. The resistors are merely "recommended", but I think it's better to have them. This means two more components in an already overcrowded area of the board. 2) Joerg has pointed out that the use of a via to connect V2 and V3 [2] to ground is far from optimal and that it would be better to have a more direct connection. To have a bit more room, I was thinking of moving some things that currently sit between USB and the MCU to the other side of the PCB, which is relatively empty. Joerg suggested a "bridge" design that would also greatly improve the ESD protection, killing two birds with one stone: http://downloads.qi-hardware.com/people/werner/tmp/esd-moat-and-bridge2.png Unrelated to all this, I found that I connected DISP_SCLK to the wrong pin. It should be on PTD5 but it's on PTD6. Only the former can be used as SPI clock. I'm currently bit-banging all SPI, so it doesn't matter, but going forward, this wants fixing. [1] http://cache.freescale.com/files/32bit/doc/quick_ref_guide/KLQRUG.pdf [2] http://downloads.qi-hardware.com/people/werner/anelok/tmp/anelok-20131005.pdf - Werner _______________________________________________ Qi Hardware Discussion List Mail to list (members only): [email protected] Subscribe or Unsubscribe: http://lists.en.qi-hardware.com/mailman/listinfo/discussion
