I created this Hackaday project just for the sake of keeping my development notes somewhere, and stop spamming Odroid forum with unrelated posts.

So, I'm halfway done with the PCB design of the board matching the project description.

The FPGA of choice is iCE40HX4K in TQFP144, which is cheap and through icestorm toolchain it can be used as 'HX8K for a fraction of a price.

In the past I have already done VGA output on ICE40, as well as the programming interface through SPI on ARM SBCs, so I'm not worried about those at all.

Routing two parallel e-ink outputs was a challenge, and signal integrity worries me a little, as trace branching could not be avoided. But experience shows that engineers worry too much about that, heh.

I added 64Mb PSRAM which should be easy enough to drive, as it has an interface almost identical to SRAM. I am not entirely sure whether a frame buffer will be necessary at all, but I cannot rule it out either. Again, I didn't care too much about equal trace lengths and such. Should be fine at 50MHz DDR.

The programming interface is a 10-pin 2,54mm IDC compatible with Olimex ice40 evalboards. It consists of SPI signals for flashing the on-board Flash and two misc lines which I normally use as a UART debug IF.

Since there is a dedicated e-ink PMIC that requires I2C config, I guess that I'll have to make another connector just for that. I'll give Linux a chance to configure it using a mainline driver (if it exists?), but if not I'll just bitbang a config sequence from FPGA. 

The board will be JLC'ed without assembly as I don't need 5 pieces. Hand soldering will be a nightmare, but what's December for, right?