Re: V5 & AMP on one board

Posted by sbt on
URL: http://bluesaab-forum.90.s1.nabble.com/V5-AMP-on-one-board-tp972p975.html

homerisback wrote

Once again, I'm open to comments on this work and if you have suggestions to improve it, I'd be happy to look at them. Actually, I don't like the number of vias I added on the PCB, it's too "heavy"...
Stay tuned ;)

Antoine,

Nice start; I've been pushing for integrated amp ever since it became clear every board should have one. I was really tempted to have a go myself, but no time...

To free up some PCB space, here are some suggestions:

1) You can hang the RN52 antenna area over the edge of the main board. In fact, according to the data sheet, this is preferred. This will free up some space on the board. I'd also notch the area where the antenna is. I don't think there's enough room in the box for it to completely clear the standard board size;
2) As well as the RN52_Firmware header, the FTDI 6 pin header and 4 pin UART headers are not strictly needed;
3) You can leave out the component value labels and LED colours. Only the IDs are really needed to build the board, since the schematic is authoritative;
4) Seth and Karlis may disagree with this, but I don't believe the 555 and associated components introduced in v5.1 are needed. There was a software bug that prevented the ATMEGA's in built watchdog from working correctly, but this has been fixed (since v4.0 release) and the built-in watchdog should be able to cope with any issues. I've not had a crash/hang on my v5.0 since the fix went in. I'm hoping for a 4.1 release to get this into the 'wild' ASAP.

You can spend a lot of time trying to reduce vias, but that's not as important in my view as getting good noise/RF conformance. I'd be trying to maximise spacing between components, and potential reflection points in data paths. Also, even though they're balanced, I'd be trying to keep the analogue audio paths as far away from the CAN/serial lines as possible. To ensure you benefit from the balancing, keep the + and - lines of each channel as close to each other as possible.

Good luck.

Cheers,
Sam.