Altera cyclone circuit board indicator

[Ben Popoola]

I wish to connect a LED to the CONF_DONE pin of a cyclone FPGA to
indicate when configuration has been completed.

The CONF_DONE pin is an open collector pin that is pulled high via a 10K
resistor when configuration is completed.

Do I connect my circuit board indicator to ground (through another
resistor) or should I connect it to the power rail?

Thanks
Ben

 

[Khim Bittle]

On Thu, 23 Oct 2003 04:31:26 +0100, Ben Popoola
<b.popoola@ntlworld.com> wrote:

I wish to connect a LED to the CONF_DONE pin of a cyclone FPGA to
indicate when configuration has been completed.

The CONF_DONE pin is an open collector pin that is pulled high via a 10K
resistor when configuration is completed.

Do I connect my circuit board indicator to ground (through another
resistor) or should I connect it to the power rail?

Thanks
Ben

Another idea which I just used on a cyclone design .. i put a small
smt led from the NCEO pin to ground via a 220 resistor, the led
flashes when power is first applied during configuration, if the led
remains on there is a problem. I like this particularly for multiple
cyclones loading from one flash device since each cyclone can have
it's own led beside the chip indicating which cyclone did not
configure instead of using the conf_done pins because these are tied
together for a multiple cyclone string and cannot point to the chip.

 

[Ben Popoola]

Khim Bittle wrote:

On Thu, 23 Oct 2003 04:31:26 +0100, Ben Popoola
b.popoola@ntlworld.com> wrote:


I wish to connect a LED to the CONF_DONE pin of a cyclone FPGA to
indicate when configuration has been completed.

The CONF_DONE pin is an open collector pin that is pulled high via a 10K
resistor when configuration is completed.

Do I connect my circuit board indicator to ground (through another
resistor) or should I connect it to the power rail?

Thanks
Ben



Another idea which I just used on a cyclone design .. i put a small
smt led from the NCEO pin to ground via a 220 resistor, the led
flashes when power is first applied during configuration, if the led
remains on there is a problem. I like this particularly for multiple
cyclones loading from one flash device since each cyclone can have
it's own led beside the chip indicating which cyclone did not
configure instead of using the conf_done pins because these are tied
together for a multiple cyclone string and cannot point to the chip.

This sounds like a reasonable alternative solution but I would like the
indicator to come on after configuration.