Devo 12

You underestimate the number of tasks (and other hobbies / responsibilities) I have going on at any one time. The Devo12 has been out of its box just long enough for me to take a single picture.

As I've stated before, a proper Devo12 implementation will be quite an undertaking since the larger screen will require redesigning virtually every configuration page.

My hope is to do a crude port which uses the devo8 interface (scaled to the devo12 screen) as a quick&dirty 1st implementation so that we can at least have something to start with.

I certainly won't start until I'm done with the Devo7e work though.

Don't do the latter.
While I haven't checked it yet, the memory layout may be different on the devo12. If it is, you could corrupt your bootloader and have something which requires a SWD debugger to fix. That is the worst case scenario.
The best case scenario is that everything works but you can't see anything on the screeen.

Now that the Devo7e code is merged, I've started looking at the Devo12.
Interestingly, they used a 2MB SPI flash (probably for model and configuration files) and a 2nd 16MB parallel-flash (probably for the images). The devo8/10 have a 4MB SPI flash, and the Devo7e has a 2MB SPI flash. You might say 'Cool 16MB + 2MB is way bigger than 4MB'. However, there is a problem. the 16MB ROM has 128kB page sizes whereas the SPI flash has 4kB page sizes. This means you need to erase 128kB at a time on the big flash chip. Additionally, while there is a 2MB SDRAM, it is dedicated to the display and I don't think is accessible by the MCU. That leaves us with 64kB of RAM for use. That makes building a filesystem quite challenging, since you can't easily store more than 1 file per page unless you have the ability to copy the contents of a flash page to memory, modify and write it back out.

So we might end up with the Devo12 only supporting a usb filesystem for the models, and not for the rest of the system.

Additionally, the Graphics driver they used is not very popular, so I haven't yet found an example library for it (well, epson provides one, but it isn't useful to me). That means writing my own, which will slow things down a little.

On the plus side, this thing is very cool. It is really well built (much better than any of the other Walkera Tx), and weighs less than my Devo10 despite being much bigger.

A bit more Devo12 info:
I've mapped out a bunch of the pins, though by no means all of them. One annoyance is that the Trainer port is not attached to the UART, so getting a debug terminal is harder.
Still, I can power on/off the Tx, and read/write from the SPI flash, so that is a good beginning.

Well, after a bunch of banging my head against the wall, I finally figured out how to get the display working. So that is one more big item checked off.

I am going to limit the screen to 320x240x16 initially so that we can reuse the Devo8 GUI, but I am able to write to the entire 480x272 screen in 24bit color right now.

I still need to learn how to interface with the parallel-ROM, and figure out how I want to use it.

I also need to check if the touch sensor works the same way it does on the Devo8.

After that it is mostly a matter of figuring out all the buttons and switches, and then we should have a Devo8 port working on this beast.

While they did not use the same pins for the PPM and UART, they were nice enough to put pin-headers on the UART pins on the circuit board, so hooking up a debug terminal was easy after all.

Well, I'm getting really close I hope.
I have all analog inputs working
I have all switches working
I have all buttons working
I have the SPI and Parallel ROMS working

I have not yet tested the touch sensor, but it is the same one used on the devo8, so I assume it'll just work.
I have not yet figured out how sound works on this Tx.
I have not yet tested USB, though I assume that will just-work too

All the work I am doing now is just hardware enabling. Once I've got all the hardware functional and documented, I then start working on the actual transmitter code.

One thing I found is that to support the Devo12 properly, I need to rename the dual-rate switches in all transmitters. All switches will be one-hot instead of binary. that means that 'AIL DR' becomes 'AIL DR0' and 'AIL DR1' (or in the case of the Devo12 AIL DR0, AIL DR1, AIL DR2)
However, I am not yet sure how to make this change backwards compatible with all existing model files.

I also learned how to detect charging and 'powered by outlet' conditions. I think I can do it on the Devo8 too, though mine is too modified and no longer detects these conditions.

PhracturedBlue wrote: One thing I found is that to support the Devo12 properly, I need to rename the dual-rate switches in all transmitters. All switches will be one-hot instead of binary. that means that 'AIL DR' becomes 'AIL DR0' and 'AIL DR1' (or in the case of the Devo12 AIL DR0, AIL DR1, AIL DR2)
However, I am not yet sure how to make this change backwards compatible with all existing model files.

It's easy. All the previous dr key value is equivalent of the new dr1...

AIL DR = AIL DR1
!AIL DR = AIL DR0

We can read and parse from ini file 'old' or 'new' value and then save to ini file only 'new' value.

Flashing back to the original firmware is fine, I've done it several times.
You will loose all settings and models though, unlike the devo6/8/10