Doing a project with SPI and MP3 player using the VS1003B MP3 decoder chip. I've found a lot of projects on the net that I can try out. One such project is posted on the VSLI (the maker of the VS1003B decoder) site. Attached is the schematic. Also attached is the VS1003B datasheet.
As far as I am concerned, the two GNDs (analog and digital) are basically the same GND from the power source? I have gotten it working on the breadboard, which is very noisy, because I can hear a little tiny buzzy sound in the background. I figured that once I have the PCB made with the ground plane, things will be better. However, I would like know if putting a low-pass filter (a resistor and a ceramic cap) on each of the LEFT and RIGHT output pins of the VS1003B will eliminate the buzzing sound. I am about to try but just wanted to see if there is a better solution.
And additional quesitons:
-I use the attached SMD 3.5mm earphone jack. (See the attached footprint image.) I figured out that pin #2 is for the "common buffer for the headphones." Pins #3 and #4 are for the LEFT and RIGHT outputs from the VS1003B. I am not sure about pin #5. When I try to ground it, the buzzing is louder, and I am not sure leaving pin #5 unconnected (to whatever it's supposed to be connected) is causing the tiny buzzing sound in the background. Unfortunately, I don't have the entire datasheet except the attached footprints.
-This is my 1st time dealing with very sensitive analog stuff. Wow! The breadboard is full a noise. By just moving even one of the shielded wires, the thing won't work. I have used so many 0.1uF caps. Besides the ground plane and all analog components to one area and digital components to one area on the board, are there other suggestions that I need to follow to ensure stability in the entire circuit as shown in the attached schematic?