UART through EMIO

[andsan]

Hi,

I'm working on a custom board with a xc7z020. In this board both UART interfaces are mapped to the EMIO, and then routed through the PL. I'm using PlanAhead and SDK 2013.1 versions, and I'm trying to run the SDK "Hello World" example: super simple software. The problem is that the Zynq doesn't send anything to my computer.

I've already checked these possible errors:

• The serial communication between my computer and the board is OK. It reaches correctly the UART transceiver.
I do receive the signal from the transceiver in the PL, so the board is OK too.

About the solutions proposed in other threads, I've included an AXI interface in the FPGA and also tried the programming sequence that enables the level-shifters, but obtained no results.

So at this point I'm quite lost. After all the previous tests I suppose that the problem is in the PS-PL connection, but I have no idea on how to solve it.

Any help is appreciated.

Regards,

Andrés.

[andsan]

Updating with some more info:

Using Vivado 14.4, I've mapped the UART interface to the EMIO on the Zynq ZC702 development board, so I can read the TX output on the PMOD pins. It works: I can run my Hello World app using the SDK debugger and through the JTAG cable too.

Then I created another project (also using Vivado) and followed the same workflow, but this time targetting my board. Now the problem is that when I launch my app using the SDK debug mode I cannot pause or resume my program: I can only stop the processor. Awkwardly the SDK doesn't throw any error, it just loads the app on the Zynq and tries to run it, with no effect.

[andsan · Accepted solution]

Problem solved: the DDR was malfunctioning and the app wasn't even being loaded by the SDK onto the Zynq. I configured the linker to load the code in the OCM and now the application and the UART communication through EMIO are working properly.