I have made a short video about some progress on the openHiFi project:
It is based on Procyon and a DAC (WM8740) board I got in the last batch of PCBs. Though it doesn’t sound great in the video it does in real life. FLAC and WAV 44.1 KHz/16-bit (Red Book) are the only current supported formats and will be until the full openHiFi is complete as I only have CD audio sources.
It is good to see the core function of the player work but there is much left to do.
We used SeeedStudio’s Fusion service to make the prototype Cygni and Procyon PCBs. Cygni had no issues. We can’t say the same for Procyon. We built up the board only to be burned by our LDO. We found that some of the PCBs we got from Seeed have VDD shorted to GND! Given that we used 8 mil clearances and Seeed specs their boards to 6 mil this was quite unexpected. In fact these are the first miss-manufactured PCBs we have ever had.
Some of the PCBs seem okay though (so far). In fact we were able to attach our JTAG to the MPU and talk to it. Unfortunately the C1 revision of LM3S9B90 has a flash patch that means mass erase cannot be used. This is making programming a bit harder than usual, enough so that we have ordered a later revision (C3) of LM3S9B90.
Slowly cutting the boards apart revealed that the shorts were at edges of zones and lines rather than vias in general. We can only speculate the copper etch time was not long enough for a few of the boards, and that there is a thin copper residue we can’t see easily in places.
The new chips are in the mail today so perhaps next week there will be some more progress on Procyon.
We are pleased to report there are no major issues with revision 1 of the Cygni PCB. The docs page has been updated with the correct PCB layout.
