I am targeting an SAM D11, right number of I/Os, in small package (20 ball WLCSP), just not quite enough Flash...
Initially, I created an ASF configuration with USB, SPI, SSD1306 OLED display, Timer, and GPIOs. (It was WAY too big for the flash.)
I now have an ASF USB configuration, to which I added my own GPIO, Timer, and SPI routines (along with some of the Adafruit SSD1306 library). With "almost" everything implemented it is compiling to 100.0%. Yup 16384 bytes flash and 87% sram (which I have not yet optimized). I have stripped out some of the USB to the point that anything I now touch causes it to fail. I just need a few more switch cases for handling USB out reports from the host.
Is there another option? (The ATmega32U2 in the QFN32 is 4x larger size, which is a major problem.)
I am using the SAM D11 Xplained Pro with the OLED1 Xplained Pro for development. I have not yet tackled rolling my own USB as the SPI register configuration was headache enough! Nor have I looked into assembly optimization. (I am considering a reduced character set for the OLED.)
So I just thought I would ask before I enter the black hole, if anyone had implemented a USB on the D11?