Max10: ADC not working with .pof file

Altera_Forum · ‎02-12-2018

Hi

I'm currently working with Max10M16DAF256 and I have a problem with the ADC. When using .sof file it works fine. When using .pof file the ADC does not work anymore, i.e ADC data is always zero, while the others components work correctly.

I have also seen that after programming with .pof file and still let the suppy voltage on, the ADC works. But after reset the supply voltage (switch off and on again), it doesn't work anymore.

Some hints on the problem please.

Thanks

Altera_Forum · ‎02-12-2018

Is this your own design board or a development board?

If the latter then you need to confirm check how you release the ADC IP from reset. Hold it in reset 'a little longer' following power up. Sorry this might sound a little vague. This seems to be a regular issue on the forum that doesn't seem to have received a clear, reliable solution.

If this is your own board then you need to check the above and ensure the rails rise monotonically. There are no sequencing requirements but if the don't rise appropriately - not meeting the Tramp time - the device will misbehave. Refer to 'Figure 3. Monitored Power Supplies Ramp Up' in the 'power management user guide (https://www.altera.com/en_us/pdfs/literature/hb/max-10/ug_m10_pwr.pdf)'.

Cheers,

Alex

PS. be sure to post any fix you find...

Altera_Forum · ‎02-12-2018

Hi Alex

Thanks for fast response.

I also found the same problem with Max10 ADC in another thread, but like you said there is no solution for this.

The board is our self design board. The problem is that many of our boards are working fine with ".pof"-file, and some of them have this ADC problem. For the boards with ADC problem, we investigated in the hardware of these boards but unfortunately we didn't find any problem with the hardware. Like mentioned above, the boards are working with ".sof" and even ".pof"-file when the supply voltage is always on. After the supply voltage is reset, the ADC does no more work while the rest is still working correctly.

Thanks

Bien

Altera_Forum · ‎02-13-2018

This makes me believe even more this issue may be power related. I suspect you have one (or more) slightly slow or under rated supplies. You're clearly on the edge of whatever the issue is given you have working boards.

Can you take a non working board, disconnect the power supplies and power it from bench supplies? My concern is that an under rated rail isn't up to supplying the inrush required and dips causing the POR circuitry a problem, which (perhaps) isn't documented.

Cheers,

Alex

Altera_Forum · ‎02-20-2018

Hi Alex

You're right. I did some investigation in the power supplies for Max10, and it seems like our analog supply takes quite long until it reaches full voltage level (we're using Max10 dual supply device, which requires two digital supplies and 1 analog supply).

As in Max10 Power management user guide, it looks like only the last power supply for Max10 matter (attached picture), so we tried to swtich on the analog supply first and wait for it to reach max level, and then switch on the other two digital supplies, which take only few hundred µs to reach max level. This helps the not-working ADC to become working sporatically (not always working).

However when we take a working board (ADC always works) and do the reverse sequence (i.e let two digital supplies on first, then the analog supply), the ADC is still working (we expected that it should not work anymore).

So somehow the ADC problem relates to the power supply sequence and the ramp time of power supplies, but a clear explanation for this problem has been not found yet.

Thanks,