I have just finished mounting the µC board, to test the firmware and, after a little trimming, everything worked. The fact that the board connects directly to the PICkit2 programmer, means that I can program it , and test it while the thing is on. I have updated the code in the SVN, to reflect the changes. All there is left, are three holes in the front and oh I gotta put a lid on it.

The firmware for the DAC input selector has been debugged extensively, and now seems ready for real life testing. The source is here: SPDIF input selector source. The firmware has a manual, and an automatic selection mode.

  • If the button is pushed for less than about 2 seconds, the selector enters manual mode, and skip to the next input.
  • If the button is held for longer that 2 seconds, the firmware scans each input for one second and selects the first input that has data (audio).

The firmware works by sniffing the I2S data line to the DAC, to see if anything is going on there. To prevent the DAC from playing anything, before an input is selected, a relay has been added to the DAC board, to only enable the I2S data line to the DAC, when a signal has been selected.

When the project is finished the compiled firmware will be made available along with the rest of the design files.

Generated on 2018-05-03 01:14:21.921345