PlatformIO on emonpi can't access tty port

technerdian · 2017-11-29T13:07:52.130Z

I’m modifying the firmware to return real and apparent power from both CTs in order to use these to calculate the power factor in a Virtual Feed in emoncms. I’ve bought 4 emonpi units and am doing this with all of them.

I have completed this on one emonpi unit - happy days!

On the second unit however, the firmware builds but PlatformIO fails to upload. Upon trying to connect to /dev/ttyAMA0 it fails with message: “*** [upload] Device or resource busy”

Any ideas? Do I need to open the unit and start checking connections?

Thanks,

Gareth.

glyn.hudson · 2017-11-29T13:22:49.004Z

Nice work.Have you stopped emonhub?

sudo service emonhub stop

Also I think platformio will require sudo

technerdian · 2017-11-29T14:40:43.062Z

Good thought.

The page I followed last time had both of those in it. Part 1/3: PlatformIO open-source embedded development ecosystem - Blog | OpenEnergyMonitor

Today I was using Firmware Modification - Guide | OpenEnergyMonitor which doesn’t mention either.

However, even stopping emoncms and using sudo to run pio … I’m getting the same error.

I’m going to work on the next one and see if it behaves differently.

technerdian · 2017-11-29T15:24:04.105Z

Never mind! It helps if you stop the right service.

I stopped emoncms … now having had lunch I paid attention and stopped emonhub.

Thanks Glyn.

glyn.hudson · 2017-11-29T15:51:53.299Z

Excellent. Ah yes, it’s emonhub you need to stop. Emonhub is a python service which reads the serial data from the emonPi on /dev/ttyAMA0 and posts to Emoncms / MQTT.

The section 3b “Using ttyAMA0 GPIO to upload direct to emonPi” at the end of the Platformio blog post mentiones that stopping emohub is required.