This may come as a surprise, but with the Parallella 1.1 now ramping up production we are already in a rush to get Parallella 2.0 out the door!
The DDR3 part that we are using on the board was unfortunately "End of Lifed" last August and we just placed our last time buy. This means that the total number of Parallella-1 produced will be limited to ~20,000
Unfortunately there are no pin compatible parts so we need to respin the board. This work is already in progress, but we want to reach out to you to get feedback regarding suggestions for changes to the board. Here's the plan as it stands, please respond to this thread to approve/disapprove these changes and to add your own thoughts about features needed. We are trying to keep these changes as small as possible to minimize design cost, compatibility, and risk.
Change #1:
Change DDR memory design to use 2 16-bit wide DDR memory chips instead of a single chip (twin die) 32-bit wide chip.
Why: 32-bit wide interfaces no longer supported well.
Change #2:
Use a standard USB host port connector (major change!)
Why: More mechanically sound and removes need for annoying adapter cable.
Change #3:
Remove the 2nd USB chip.(next to the ethernet RJ45). Connector stays for power delivery.
Why: Questionable feature to start with and we don't have the resources to support the feature. Connect with ethernet, Wifi, GPIO.
Change #4:
Move the tall 100uF caps to the bottom side
Why: Allow for more efficient heat sinks for the Epiphany/Zynq
Change #5:
Move the mounting hole 5V jumper pin
Why: Mechanically wrong placement
Change #6:
Move the reset pin
Why: Get out of the way from the heatsink
Change #7:
Move the diodes to central location
Why: Makes for easier case design (ala Raspberry Pi)
Change #8:
Change the UART_TX input pull down to "pullup"
Why: Verified to be more robust to noise (still verifying..)
Change #9:
Change Epiphany reset signal to 1.8V
Why: Currently being driven from a 2.5V bank..which is not that healthy long term.)
Any and all inputs are welcome! Speak now or forever hold your peace.
Andreas