DFPlayer Mini Logic Levels
Bart.Braun 2023-07-09 20:02:00 1701 Views4 Replies I am using RX and TX to connect my DFPlayer Mini to a Teensy 4.1 which runs at 3V3. To power the project, I have a 5V power supply. The Teensy handles 5V very well, and the specs on the DFPLayer Mini say it should as well. I found that if I ran the DFPlayer Mini with the available 3V3, the volume was not sufficient. I have been running the RX and TX through a level shifter, mostly to protect the Teensy.
Here is my question:
What are the logic levels for the RX pin, the TX pin and the BUSY pin?
I was assuming they would match the voltage in, but I read (not in any official document) that the pins are 3V3 or possibly 3V1. I could find nothing in the official documentation that confirms this. I may have missed it.
Any help on this would be greatly appreciated.
Thanks for the information. One question I have is what are the official levels of DAC_L and DAC_R? 0V - 3.3V or 0V - VCC?
ridilen I emailed DFRobot tech support and they got back to me very quickly. It was very impressive. Thank you DFRobot! Here is what they said…
The operating voltage of DFPlayer Mini and the TTL level of it are both 3.3V. So you do not need any resistor/ logic shifter to connect the module onto your 3.3V main board.
On the power supply side, we built a voltage regulator circuit, so you can input 3.3-5V voltage to use DFPlayer Mini. We recommend no more than 5.2V
Bart.Braun 
This diagram seems to indicate 3V3 logic levels, but does not explicitly say the logic level is 3V3.
https://picaxe.com/docs/spe033.pdf
Bart.Braun 
