I’m building some PCB hardware and everything works great, but my first prototype is a little noisy (background noise when i turn up the volume).
I know that a ground plane would help, but i’m confused because i also know that the daisy seed has digital ground and analog ground.
Which net should the ground plane be?
Should i have 2 ground planes, one for each net on different layers?
When looking at the daisy pod, it seems that there is only a small plane near the audio in and out traces, should i just make a small AGND plane around those?
Any info you can give would be very helpful, thanks!
I am also working on a design with the daisy seed and wondering the same thing. The spec sheet says to connect agnd and dgnd together on your own hardware, but as someone new to mixed signal design, I wonder where you would do this. Can you have a single ground plane that connects to both dgnd and agnd pins, as well as the audio jacks? Or will you experience digital noise in your audio that would be mitigated by separating the grounds in some way?
Hello, i’m reporting back in case anyone else is confused about this in the future.
After some months of experimenting i now have a pretty complex PCB that is as interfearance free and clean sounding as other devices i have tested by the likes of roland and korg. (When powered via a 9v power supply to the pins on the seed, not USB, that’s noisy as hell ).
By complex i mean that it has 20+ PWM lines powering RGB leds, MIDI signal lines and 20 + pots and buttons.
Right now my setup is this:
4 layer PCB
Top layer: Audio traces only, GND fill the entire layer
Inner Layer 1: GND plane. I think this helps protect the audio from PWM etc…
Inner layer 2: Other Signal traces
bottom layer: other signal traces, GND fill entire layer
IMPORTANT NOTE: i am an electronics noob, i only started learning it a year ago. Perhaps this setup i have is not optimal, or perhaps it’s going to explode!
But it’s sounding great right now, so perhaps it’s an option for others who are also confused.
).