Hi
Driving an i2c programmable potentiometer (DS3502) from an itsy bitsy 5v controller. Testing it using the provided arduino code example software from the Adafruit tutorial page. The program reports 0v, 2.57v and 5.00v from digital values 0, 63 and 127 respectively. However, using a calibrated DVM the actual voltages read at the programmable pot's RW output are 0v, 2.18v and 4.34v. This is with the pot's RW link to the microcontroller's A0 input disconnected to avoid any loading implications. I've checked the wiring and it's spot on. Even tried supplying the pot's Vcc from the itsy bitsy's 5V and USB outputs. Output voltages with these two options are close enough to remove Vcc as the source of the problem (actually measured as 5.08v with the same DVM).
Is there some inherent resistance in the pot's FET chain that I'm not aware of ?
Again, any help appreciated.
Programmable potentiometer DS3502 Low Voltage
Moderators: adafruit_support_bill, adafruit
Please be positive and constructive with your questions and comments.
- AdrianPW
- Posts: 21
- Joined: Sat Jul 20, 2019 9:38 am
- adafruit_support_mike
- Posts: 67454
- Joined: Thu Feb 11, 2010 2:51 pm
Re: Programmable potentiometer DS3502 Low Voltage
The end-to-end resistance through the DS3502's pot (from the RH pin to the RL pin) is 10k.
You should be able to connect your high and low voltages directly to RH and RL.
You should be able to connect your high and low voltages directly to RH and RL.
- AdrianPW
- Posts: 21
- Joined: Sat Jul 20, 2019 9:38 am
Re: Programmable potentiometer DS3502 Low Voltage
Problem solved. Rebuilt circuit on new protoboard with new dupont wires.
Now works perfectly.
Now works perfectly.
- adafruit_support_mike
- Posts: 67454
- Joined: Thu Feb 11, 2010 2:51 pm
Re: Programmable potentiometer DS3502 Low Voltage
Glad to hear you got it working. Happy hacking!
Please be positive and constructive with your questions and comments.