Added UserText OSD support on Rapidfire Module

[cnheider]

I also reworked the Rapidfire SPI implementation using the excellent work done by GOROman

https://github.com/GOROman/rapidFIRE_SPI

I implemented OSD support for the Rapidfire Module in ELRS Backpack and verified that it works with RotorHazard.

https://github.com/i-am-grub/VRxC_ELRS

I will post some screenshots later.

[cnheider]

There is a bit of a quirk with the placement of the OSD which seems to be a bit random, unfortunately.

[JyeSmith]

I'm under the impression that the custom osd has been broken... since forever. When was this fixed or what has changed?

[cnheider]

Dunno, the SPI documentation was a bit off as well. I am using Rapidfire Brain v1.3.3. (Latest)
Kudos to @GOROman for figuring this one.
Would be great with an update from the Rapidfire devs.

[vkolotov]

Hey just wondering if you have to downgrade RadpidFire FW to a specific version or it works even with the latest FW?
Wanted to test this, how can I do? I have a backpack installed in my RapidFire module running the latest backpack FW, how do I flash it with this PR? Cheers.

[vkolotov]

Hey @cnheider , I've just tested your PR on my HDZero + Rapidfire + EP82. It works, I can see messaged! Great result! However there are a few issues:

• Because it can only display one line (is this true?), there is a race condition between messages, e.g. "Lap 1..2" and "Lap time", sometimes the first wins sometimes the second so that some messages get lost/ overwritten.
• (probably because of the first issue ^^) looks like the backpack shows some old messages, I suspect messages that was not able to be displayed), e.g. I can definitely see laptime from some previous laps, it is lagging behind.

If it is the case that Rapidfire can only show a single line, then perhaps we should display only those ones that are important. I'd say that would be your laptime. Or maybe somehow format them in one line?