01-09-2018, 05:58 AM
(01-08-2018, 06:45 PM)GaryLa Wrote:(01-08-2018, 09:35 AM)dkryder Wrote: i've also wondered and it occurred to me that the board itself , or i guess the chip [cpu] and basic outlying circuits had a design purpose of android tv box and not a multipurpose learning board like the rpi.
All of that is understandable and no one is suggesting otherwise.
Electrically, we are wondering why bother to bring out an SPI like this?
Also, why say the 40-pin layout is compatible with RPi if there is no intent for the board to be used in this arena.
It is compatible. That is, GND, +3, +5 are exactly the same. The GPIOs are in the same positions including SCL, SDA and the SPI pins.
The issue is the lack of a Chip Select associated with the SPI they brought out. It's as if they brought out the wrong select line. The naming suggests they were trying to bring out CS0 and CS1 of Module 2. But instead brought out CS0 of Module 2, and CS1 of module 0.
Gary, I think you’re almost right.
AFAICT, there is only a single chip select on SPI module 2. That’s a limit of the 3328 SoC used on the Rock64 board.
I believe there is (understandably) a massive shared core IP between the RK33series SoCs.
3328 with 316 contacts, 3368 with 453 contacts and the 3399 with 828.
I think the 3328 TRM contains info that is not relevant to its physical package (such as the additional two SPI modules) which are probably connected and exposed on one of the other SoCs.
I like the Rock for its USB3, dual Ethernet, 4GB RAM and quad core. You’re right that it’s not as useful compatibility wise as a Pi. But way more powerful.
I gave up largely with the header. I’m using downstream peripherals off the USB port.
Ta.