Category Archives: Boards

CPiLD

Posted on by Brian

CPiLD is a CPLD board for Raspberry Pi, it also has an I2C buffer chip.

I would say the major points are:

  • 5 volt tolerance
  • breakout to breadboard
  • I/O expansion
  • Interface conversion (e.g. SPI to I2S)
  • education: learn HDL or logic circuits

The board is based on XC9572XL in a 64 LQFP package.

Check the docs section for a port of the XSVF player for Raspberry-Pi and more detail on the board.

The default image for the CPLD is a SPI bus expander buffer. It buffers all the I/Os and adds 8 inputs and 16 outputs.

If you think you would want one, leave a comment. If there is enough interest there will be a kickstarter for them.

PCB builds

Posted on by Brian

Among the PCBs I got back was a version of BasicUART V2 that uses FT232RL in place of MCP2200. The previous version of this design had a problem with a zone not connecting to a GND pin, which caused it to be flaky at best.

I built up one last night and it worked nicely. I will get to updating the docs and producing a few of these in the near future.

Another design in the PCB batch was a high speed DAC conversion board. This board had some issues. First the footprint for the DAC chip wasn’t correct (I needed the wide version but used the narrow version opps!). Second the opamp circuit was unstable. I was able to hack fixes for both onto the PCB to do some testing. After the fixes the output was not bad at all. It still needs improvement and that will likely require another 2 PCB iterations for what I have in mind to really test fully.

MSPism got a minor tweak to its design, which looks fine but still needs to be tested. I have some firmware written for MSPism but it isn’t what I envisioned as the final features which is why it still hasn’t been released and put on sale. If you feel strongly I should just release what I have done, sound off.

The other boards have yet to be built up for testing of any kind. One of them is for a contract and the other is a new design, for an old idea.

openHiFi Update

Posted on by Brian

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.

Free Friday: Cygni PCB

Posted on by Brian

This will be the last Free Friday for 2011 as teho Labs will be closed Dec 15th until the new year. Encouraged by seeing some free builds of Cygni this week Cygni is back up. The BasicUART though it did work has a technical violation of the datasheet that could cause an issue because a flood fill problem I missed so it will be remade, after that it will be available at least as an add on again to board orders and perhaps by itself.

A random commenter in 24 hours will win the PCB.

Because of the lab closure be sure to get any orders in before the 15th!