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Visitor
Visitor
5,062 Views
Registered: ‎03-09-2011

internally reset FPGA

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Is there any way to internally assert PROGRAM_B or the equivalent? I'd like to programmatically reconfigure a Virtex5, i.e. to initiate a configuration process on-the-fly from my user logic. I do not have any means to reset/reprogram the FPGA from an external processor, other than JTAG. The board has an SPI configuration interface; if I can reset the FPGA it will configure from the SPI flash, without me having to send a JPROGRAM (or whatever it is) command over JTAG.

 

Please note I'm not asking about partial reconfiguration - I just want a full reconfiguration. And I'm not asking about a global reset (GSR) to the previously-programmed configuration.

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Historian
Historian
6,335 Views
Registered: ‎02-25-2008

You need a spare output pin that you can wrap around and connect, external to the FPGA, to PROGRAM_B. That output should be open-drain. Drive it low, it yanks down on PROGRAM_B, and once configuration starts, the logic that drives it goes away and the pin itself is tristated or pulled up (depending on the state of the HSWAPEN pin).

----------------------------Yes, I do this for a living.

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Historian
Historian
6,336 Views
Registered: ‎02-25-2008

You need a spare output pin that you can wrap around and connect, external to the FPGA, to PROGRAM_B. That output should be open-drain. Drive it low, it yanks down on PROGRAM_B, and once configuration starts, the logic that drives it goes away and the pin itself is tristated or pulled up (depending on the state of the HSWAPEN pin).

----------------------------Yes, I do this for a living.

View solution in original post

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