Since I had good experience with the GHI Music module I designed it in to a new project. Later on I found it as discontinued on the website.
This forced me to design my own board encapsulating the Music module fully compatible with GHI Music module. As said the card contains the music line output, aswell as a SD card slot, 4x button and 4x LED.
If people are interested in this board please contact me at www.Inno3D.nl.
It would appear to me that this is just a module, rather than a mainboard with extra function. So it’s a SD module and a music module in one, and you still need your cobra or hydra or other mainboard to drive it.
Correct Brett, it’s just an collection of modules on a single board 1) SD card 2) Music module 3) 4x button 4) 4x LED.
The linear regulator placed on the board due to the fact that the VLSI VS1053 codec needs 3V3 and 1V8. The 1V8 regulator is also on the GHI Music Module (in SOT-223 package). I explicitly added an separate 3V3 as well to power from an adapter to give it optimal grounding to the VS1053 since this is on the same ground plane.
As VLSI suggested I used the Line out GBUF pin for ground which eliminates the need of large isolation caps (equal to the GHI Music Module). The GBUF indeed has a 1V23 offset. As stated in the datasheet you might use ground instead to eliminate the offset as you keep the R and C on the GBUF pin to keep it stable and add large coupling Caps. To my experience with audio you will need at least >> 100uF coupling on both Left and right if you implement it like this. In case if you connect active speakers, instead of a headphone, with there own adapter/power source you will not have any issue with this small DC offset.
Let me calculate board cost, I’ll let you guys know later.
Since the GHI Music Module was discontinued I was forced to design it myself. It works fine with the existing separate drivers for the Music Module and SD card. (although not completely in line with the modular Gadgeteer concept).
I’m sure forum members will be disappointed that the Music Module is discontinued therefore my contribution for keeping .NETMF players in the field.