X9C104 Digital Potentiometer Module for Arduino _ help :(

Other Hardware General Electronics
1

i grabbed some of these thinking tutorials would be around.. i cant find anything. and cannot workout how to connect it. need some help getting started

product
X9C104 Digital Potentiometer Module for Arduino

manual

i wanted to use one of these replace the pot on a boost\buck converter so i can control it with the arduino.

can anyone help?

thanks

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2

It may not be that simple. First you have to compare the voltage across the buck-boost converter pot to the operating voltage specs on the datasheet for the digital pot. (5V)
x9c1/x9c102-103-104-503

You have to measure the voltage across the converter pot to see if it is more than 5V. If it is , you can't use the digital pot. Which converter ?

3

i read that bit, it says max 5v? the boost converter can go up to 40v
checking with a meter there is a slightly lower voltage then the output at the pot pins (iv watched a few videos but im not solid on how the converters work)

i was hoping i could control the boost buck with arduino to make a power supply

not sure what to do next

raschemmel:
It may not be that simple. First you have to compare the voltage across the buck-boost converter pot to the operating voltage specs on the datasheet for the digital pot. (5V)
x9c1/x9c102-103-104-503

You have to measure the voltage across the converter pot to see if it is more than 5V. If it is , you can't use the digital pot. Which converter ?

4

Which converter ?

Still don't see any link for the converter. Can't help without that.

5

"and cannot work out how to connect it. need some help getting started"

The IC's pin should be routed to the Arduino as follows:

8 ─ to +5V
4 ─ to Gnd
7 ─ to Gnd, this is Chip Select (always "selected")
1 ─ to an I/O pin (your choice), this is INCrement; normally high, toggle this pin to change pot wiper val.
2 ─ to an I/O pin, this is Up/Down (HIGH is Up, LOW is Down)

I suitable for this application, and I'm not vouching for that, running the power supply with the digipot unpowered will probably not be a good thing.
You would definitely not want a circuit on the output until it's been put into a known state.

6

thanks, but i don't have any references on what code to use (an example sketch) or how to connect the output rh, rw, rl (is the output isolated and doesn't need a common ground, etc)

and it says 5 v limit but the boost or buck has more then that at the pot

7

hi, i was thinking they would all be very similar when replacing the pot with a digi-pot. links below.

http://www.ebay.com.au/itm/302039611391

http://www.ebay.com.au/itm/301898638195

im hoping to control the CC and CV with the arduino and digipots

thanks

raschemmel:
Still don't see any link for the converter. Can't help without that.

8

OP: I am working on a circuit right now that uses 5 - X9C104P 's in series to control a buck/boost power supply. The X9C works as described, there is a great YouTube tutorial on how it works...

My circuit requires 0-500k to control output. The pots are used to control a ref voltage, almost no current is passed through them.

9

Hey probably solved this problem but I had a similar experience finding details about this module. Anyway this is a quick and dirty code:

#define cs 4
#define ud 5
#define inc 6

void setup() {
  // put your setup code here, to run once:

  potentiometerstart();

}

void loop() {
  // put your main code here, to run repeatedly:
 

  for (int i=0; i<100; i++){
    potUp();
    delay(500);
  }
  for (int i=0; i<100; i++){
    potDown();
    delay(500);
  }
  
  
}

void potentiometerstart(){
    pinMode(cs, OUTPUT);
    pinMode(ud,OUTPUT);
    pinMode(inc,OUTPUT);
    digitalWrite(inc,LOW);
    digitalWrite(ud,LOW);
    digitalWrite(cs,LOW);
}

void potUp(){
  digitalWrite(ud,HIGH);
  increment();
}

void potDown(){
  digitalWrite(ud,LOW);
  increment();
}

void increment() {
  digitalWrite(inc,HIGH);
  digitalWrite(inc,LOW);
}
10

hfx_dennis:
OP: I am working on a circuit right now that uses 5 - X9C104P 's in series to control a buck/boost power supply. The X9C works as described, there is a great YouTube tutorial on how it works...

https://youtu.be/iOINcW8BP3w

My circuit requires 0-500k to control output. The pots are used to control a ref voltage, almost no current is passed through them.

5 digipots in series to control a reference voltage?

Surely that's a job for a DAC and an opamp?

11

Defenestrator:
void potentiometerstart(){
pinMode(cs, OUTPUT);
pinMode(ud,OUTPUT);
pinMode(inc,OUTPUT);
digitalWrite(inc,LOW);
digitalWrite(ud,LOW);
digitalWrite(cs,LOW);
}

void increment() {
digitalWrite(inc,HIGH);
digitalWrite(inc,LOW);
}

[/tt]

I would recommend to have the inc HIGH as a default since the digipot changes on a negative edge of the inc-pin i.e. when the inc changes from HIGH to LOW.
This would also mean that the two lines in the increment() should change order. First take it LOW to start the change and then back to HIGH.
Another bonus by keeping the inc HIGH is that if you let CS go HIGH while inc is HIGH the current value for the wiper would be saved before entering power standby mode (the CS need to be high for a minimum time of 20 ms for that to happen).