The MP3 Trigger is now shipping from SparkFun, and I’ve already been asked about support for different baud rates on the serial port. As shipped, the unit supports 38.4Kbps and is not user configurable. I chose this relatively high data rate because I needed to send updates as quickly as possible to avoid clicking and distortion when dynamically altering the volume – many small changes are better than a few big ones. I understand that not everyone needs this feature, and some may want to control the MP3 Trigger from devices that don’t support such a high baud rate.
For the time being, I’ve built alternate versions of the v1.01 firmware (the version that SparkFun is shipping at this date) for 2400 and 9600 baud. Please do not ask SparkFun to modify the firmware before shipping – they are simply not able to do this on a case-by-case basis.
You can download the hex files here:
In order to make use of the above hex files, you’ll need a way to utilize the in-circuit programming connector on the MP3 Trigger. The easiest solution is to get a Cypress MiniProg for around $25. Since there is no header installed for this on the MP3 Trigger, a 5-pin male header can be used for temporary connection. The following picture shows the MiniProg and appropriate header.
The next picture shows the header inserted into the female connector of the MiniProg, then inserted into the connector on the under side of the MP3 Trigger and properly oriented.
I’ve created a forum dedicated to discussion and questions about the MP3 Trigger. If and when you get to the point of reprogramming your firmware and have questions, that’s a good place to go and it will help me get the forums going. You can also leave comments/questions here. And I’ll do my best to monitor the SparkFun forum as well.