Hello,
The recent talk about de-blobbing R8 and thus also GR8
inspired me to do a quick write up on how I see a Next Thing
Co. GR8 System-In-Package chip being used in an EOMA68
compatible card.
The latest version of the write up can be found here:
I named the project "EOMA68-GR8"
because why not.
Like Vincent I'm doing this on the side
and also with Altium.
I haven't done anything this
complex in Altium before it's likely going to be an
interesting challenge.
GR8 has TTL/RGB LCD
interface, USB2.0, I2C, SPI(SDMMC) and so on.
All the interfaces to make a
compute card compatible with EOMA68 are there.
Except if I want the card to
have "front facing" USB I'll need to include some USB HUB
chip like TI TUSB2046,
which conveniently has no firmware being a state machine.
I'll
have to look at how the interrupts go, at AXP209 PMIC and
it's routing.
And decide on
if I'll layout the NAND as the talk about blobs being
required for NAND support sounds worrying. That and seeing
in general if even a half reasonable layout is possible on
4-layer FR4 to get cheaper rates on the pcb's. At least
there's no DDR RAM to route, but the TTL/RGB fanout and
length matching is gona be chore.
One more good
reason to learn how the automated length matching in
Altium works.
Sourcing connectors and
housings in small quantities. All that fun stuff.
If anything I have missed comes to mind please mention it,
I'd rather hear it now then when I have prototype pcb's at
hand or layout nearly done.