CAN controller on PMOD or GPIO for PYNQ-z1 board

[vnne]

Hi all!

I'm currently thinking of purchasing the pynq-z1 board and hoping to set up CAN communication on it. I've read the documents regarding the PYNQ board (http://pynq.readthedocs.io) but I wasn't able to conclude on whether I would need to purchase a PMOD with it to access a CAN peripheral. From what I understood, many of the peripherals are available through the PL via PMODs or an arduino. There was also a comment stating that peripherals such as Ethernet, USB and UART, are connected externally, while all other peripherals are connected internally or routed to PL pins.

This confused me so my questions are: What do you mean by "connecting peripherals internally"? and would I need to purchase a PMOD and route my CAN controller to PMOD pins, in order to interface with CAN? (via overlays, I believe?). 

Just need some confirmation! I'm sorry if I'm asking something so basic, I'm fairly new to embedded development, especially with zynq chips but I'm keen to learn as I go!

-Vin

[jpeyron]

Hi @vnne,

The zynq processor is tied directly to certain parts on the board like the UART. UART communication through J14 can only be done through the Zynq processor. CAN communication can be reached using the Zynq processor through the emio pins on the board. Due to the way CAN works as described here you would need an external board to facilitate it since all of the i/o is 3v3. I have attached an Image of the Zynq processor for reference. We have a PmodCAN slated to come out at the end of the month that would facilitate CAN communication to other devices. This would be the way to go as long as your goal is working with CAN devices and not trying to make a CAN controller. 

cheers,

Jon