Small Zynq boards with 1.8V IO?

[Marty Ryba]

Hi, we are developing a project, and I thought the Cora-Z7-07S was the right solution, so we got 3. Now, as I'm building up the project, I hit a wall. Some of the GPIOs I need to control are 1.8V logic, not 3.3V. I thought I could just tweak the constraints and be done, but no, you can't mix the voltages on the same IO bank, and it appears all the interfaces (included the unloaded ones) are on 3.3V banks! Is there a similar small board that I should get instead, or do I need to start hacking in level shifting?

 

[JColvin]

Hi @Marty Ryba,

Yes, the banks on Digilent boards are at a fixed voltage (and is not really possible to change, not without a bunch of incredibly difficult and tedious trace cutting and rewiring, that might not even be possible depending on how the traces are routed). Unfortunately, Digilent does not have a different small board that uses 1.8 V logic (there are some boards with FMC connectors that allow for 1.8 V, but that is not what you are looking for here).

I haven't specifically looked at other vendors to know what their offerings are, though you could use something like the Pmod LVLSHFT, https://digilent.com/reference/pmod/pmodlvlshft/start, to translate the GPIO voltages to 1.8 V.

Thanks,
JColvin

[PiotrStrzelczyk]

On 1/31/2023 at 12:32 AM, JColvin said:

Yes, the banks on Digilent boards are at a fixed voltage (and is not really possible to change, not without a bunch of incredibly difficult and tedious trace cutting and rewiring, that might not even be possible depending on how the traces are routed).

Have you thought about changing the design to make it easier (like on the boards of one of your competitors, where you only need to desolder one 0Ohm resistor per bank to be able to supply your own power to this block)?

This would simplify and improve the quality of many projects in which your (competitively priced) boards could be used.