MicroZed: driving LEDs using the user MIOs of PMOD

Hi,

I want to use the user MIO that are connected to the PMOD on the MicroZed board to drive the LEDs (via transistor switch) and the MOSFET driver in my PoC design. I have several questions related to both HW and SW that I would be very grateful if someone can help:
1. What is the maximum current these MIO pins can deliver?
2. How could I control them in my SW applications? Is that possible to include these MIO pins in the file system of the Linux OS?

0 Former Member over 8 years ago

Per the Zynq data sheet ds187( http://www.xilinx.com/support/documentation/data_sheets/ds187-XC7Z010-XC7Z020-Data-Sheet.pdf ) the MIO pins can drive 8 mA. As these signals are directly connected to the Zynq device you should take care not to damage the device with electrostatic discharge or out of range voltages.

The easiest way to control the MIO under Linux is probable SysFs functions. Here are a couple of forum posts related to using SysFs:

http://zedboard.org/content/which-tutorial-linux-pl-access
http://zedboard.org/content/blink-led-linaroubuntu1110
http://zedboard.org/content/writing-gpio-linux-application-microzed

If you would prefer to write a C application under Linux and control the MIO that way there is an example in the ZedBoard Concept Tools and Techniques (CTT) tutorial that might be helpful: http://zedboard.org/support/design/1521/11

-Gary
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0 Former Member over 8 years ago in reply to Former Member

Hi Gary,

Thanks a lot for the information and quick response. Really grateful. 8mA is just good enough for me, and I am using it as o/p and I have protection circuit in place to prevent the electrostatic discharge.
I will look into the ZEDBOARD CTT example because I want to control it in C application. Will post the results here later.
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0 Former Member over 8 years ago

ZynqBooks tutorial 4A makes the LEDs cycle on ZedBoard carrier board using Vivado and a small C program. With minor changes it works for the MicroZed board u2013 and makes a great intro to Vivado BSP generation. The ZynqBooks tutorials are free to download. Then change this:

1. All references to ZedBoard become MicroZed
2. p95 step (an) u201CRun Connection Automationu201D doesn't appear as you need to add the AXI interface first:
- Re-customise IP -> clock config -> PL fabric clocks -> FCLK_CLK0 100MHZ enabled
- PS-PL config -> GP master AXI -> MAXI I/face = selected
- OK
3. p96 step (au) constraints editing: the LEDs are on different pins on the MicroZed carrier. Change u201Cset_property PACKAGE_PIN T22u201D to u201CU14u201D etc. Changes for LEDS_out[0..7] are:
From: T22,T21,U22,U21,V22,W22,U19,U14 (for ZedBoard carrier)
To: U14,U15,U18,U19,R19,V13,P14,R14 (For MicroZed carrier)
4. Note there are some minor UI differences in later versions of Vivado compared to the version used in the tutorial. Nothing major though.

You will need to use the Xilinx Platform Cable adapter to follow the tutorial to the letter.
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0 Former Member over 8 years ago in reply to Former Member

Hi Rikpage,

Thanks a lot for this information. Will look into it.
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0 Former Member over 8 years ago in reply to Former Member

Hi Gary,

Just a quick update, as promised. Based on the information you provided, I decided to use the sysfs API and managed to be successfully flashing our LEDs with these MIO exported on the PMOD connector. Thanks for your help.
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