Re: Raspberry Pi 3?

Jeremy McDermond <mcdermj@...>

On Mar 6, 2016, at 10:32 AM, 'John Wiseman' john.wiseman@... [UniversalDigitalRadio] <> wrote:

There have been some significant changes to the serial port (ttyAMA0 is now used for Bluetooth, and the new ttyS0’s speed depends on the GPU clock), so probably not without some work.
I just got a chance to check this out today after clearing some other stuff from my plate. I don’t yet have an RPi 3 (They should arrive on Friday and I’ll give another report based on that), but you can access the Mini-UART on the RPi 2 by using a device tree overlay. Add:


to your /boot/config.txt and you’ll end up with a /dev/ttyS0 that are on the same pins as /dev/ttyAMA0. Pins BCM14 and BCM15 have both UARTs available on them.

I did this and hooked up a PiDV to the RPI 2 and ran AMBEserver -i /dev/ttyS0. I then used Buster to listen to a reflector. No audio dropouts and everything seems to work fine.

The issues I’ve been seeing around using the Mini-UART are all surrounding using it as a console, not as a peripheral after boot-time. There are issues with the clocks being gated correctly and such. The firmware does some initial setup, and if you’re not careful you can gate the wrong clocks and really mess up the system. We’re watching the clock code rather closely because we are using one of the general purpose clocks on the RPi in the soon-to-be-released UDRC.

But the upshot of this all is that the PiDV should work okay on the RPi 3. I will post a definitive answer when I get a RPi 3 for testing.


John G8BPQ
Jeremy McDermond (NH6Z)
Xenotropic Systems

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