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AOrtk
Beginner
213 Views

How do I use the ADC inputs of an Intel MAX 10 FPGA as digital I/Os?

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Hello everyone,

 

I am currently using a MAX 10 FPGA (10M08SAE144C8G) on a self developed pcb. Everythings works perfect except of the ADC pins (Bank 1A) which I want to use as digital I/Os.

 

I had the intention to not use the ADC at all and followed the MAX 10 connection guidelines:

 

  • I tied VCCA1...6 to VCCA (3.3V).
  • ADC_VREF is a no connect
  • ANAIN1 is tied to GND
  • REFGND is tied to GND
  • ADCIN1...8 are used as digital I/Os (not working).

What am I doing wrong? I double checked every pin. It is definitely those pins not working.

 

First example:

 

ADCIN5 is connected to a switch. When the switch is not implemented in the pin planner/program I can measure 3.3V or 0V at ADCIN5 (depending on the state of the switch). So the circuit is working as intended. However when I implement the switch in my code i can measure only 2V or 0V at ADCIN5 (a LED wont light up because of that). I guess because the pins are somehow "configured" as ADC pins still? The guideline says you cant use ADC and digital IO function at the same time.

 

Second example:

 

I checked again to make sure the code is working.

I have two signals (named S1 & S2) coming out of two pins. One pin is a standard GPIO (Pin1) whereas the other is one of the ADCIN pins on Bank 1A (Pin2).

 

1st test:

S1 on P1 -> Signal S1 visible (3.3V)

S2 on P2 -> Signal S2 not visible (0V)

 

2nd test:

S1 on P2 -> Signal S1 not visible (0V)

S2 on P1 -> Signal S2 visible (3.3V)

 

This confirms my theory that the code is working fine as I can make both Signals visible when I move them to a standard GPIO and NOT the ADCIN pin.

 

I hope someone can tell me what I am missing. Maybe there's an option I have to activate? It's my first layout with an INTEL MAX 10 FPGA and I really like it. Everything is working fine except of these 8 ADCIN (used as digital I/O) pins.

 

 

Greetings Alex

Stay healthy

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1 Solution
AOrtk
Beginner
99 Views

Ok guys,

 

I have figured out the problem. So for anyone who might have the same problem. You don't have to set an option.

SOLUTION: The problem was the VCCIO1A pin not having contact with the power supply (3.3V).

 

Question can be closed!

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2 Replies
AOrtk
Beginner
100 Views

Ok guys,

 

I have figured out the problem. So for anyone who might have the same problem. You don't have to set an option.

SOLUTION: The problem was the VCCIO1A pin not having contact with the power supply (3.3V).

 

Question can be closed!

View solution in original post

Rahul_S_Intel1
Employee
99 Views

Hi ,

Glad that you solved the issue and reported in forum that make us the forum community success

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