Changing Voltage Levels to FPGA on Parallella

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Changing Voltage Levels to FPGA on Parallella

Postby Kalicutt » Fri Jan 08, 2016 3:33 pm

Hello,

I require 3.3V GPIO bank voltage levels, which means I need to reprogram the voltage regulators on the board to output a VDD_GPIO of 3.3 V. Is there a simple way to do this readily available?

The voltage regulator is set to its initial state through the boot procedure on the flash, which I can easily modify. Is there a simple way to change it in flash?

I2C on the Parallella can be used to program the chip while in operation. There is a project out there that does this for the Epiphany voltage level, and can even read all of the register values and confirm what the voltages are. This seems like a good starting point for changing the other voltage levels. Has someone done this before? Searches have not shown me any results on this. Link to the code: https://github.com/parallella/parallell ... management
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Re: Changing Voltage Levels to FPGA on Parallella

Postby aolofsson » Fri Jan 08, 2016 6:36 pm

Yes, changing GPIO voltage during run time works ine. Has been tested by us.
Has been used by patc on forums afaik.
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Re: Changing Voltage Levels to FPGA on Parallella

Postby Kalicutt » Mon Jan 11, 2016 4:06 pm

Any sort of guide out there for doing it (or code ready to go)? If I don't have to make and debug my own code it would save me time.
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Re: Changing Voltage Levels to FPGA on Parallella

Postby aolofsson » Mon Jan 11, 2016 4:22 pm

What's wrong with the link that you found? Just compile and run it.
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Re: Changing Voltage Levels to FPGA on Parallella

Postby Kalicutt » Mon Jan 11, 2016 4:29 pm

The software is only for changing the voltage levels to the Epiphany chip, without modification it is not possible to change the other voltage levels. Correct me if I am wrong, though.
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Re: Changing Voltage Levels to FPGA on Parallella

Postby Kalicutt » Mon Jan 11, 2016 6:57 pm

I made some simple modifications in order to set the voltage level to 3.3V so no biggy there, however I am still interested in whether or not someone knows how to change it in the boot image so this program does not have to be run.
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Re: Changing Voltage Levels to FPGA on Parallella

Postby aolofsson » Tue Jan 12, 2016 1:57 am

For u-boot, the file to look at is on github.com/parallella
parallella-uboot/board/xilinx/zynq/board.c

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Re: Changing Voltage Levels to FPGA on Parallella

Postby Kalicutt » Tue Jan 12, 2016 8:06 pm

Thanks a lot! Will give this a try ASAP.
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