Bootloader for 9X (M128) - Works

[MGeo]

Hi,

I've learned much from this forum so thought I would post a working mod on my 9X in case it helps others. I like the bootloader feature on my Taranis, and want something similar for my 9X. I also wanted to use already existing connectors if possible, AVRDUDE/eePe compatible. Maybe this already exists but I missed it? So...

I have a Turnigy 9X with the following mods:
- M128 processor mod
- Telemetry pin relocate mod on 9X main board
- FrSky DJT module with RX-TX brought out to Pin 2-5 respectively
- MAX3232 based level converter between M128 RX-TX pins and module connector pin 2-5
- LCD Backlight and backlight PWM transistor drive mod (not needed for the purposes of this post).

I started with a fairly well documented AVR109 compatible M128 bootloader avrprog_boot from http://siwawi.bauing.uni-kl.de/avr_proj ... rprog_boot. This bootloader has a few start-up options including one that goes to bootload if you pull a defined pin during power-up. I changed this to use the 9X "DOWN" button pin. So to enter bootload you hold DOWN while you power up. It runs at 38400 bps so you have to set the right AVRDUDE flag in your command options ('-b'), and of course specify the correct COM port ('-P') that matches your serial adapter (or hardware serial port if you and your computer are old enough:). You also need to tell AVRDUDE you are using and AVR109 based programmer ('-c').

With this option it exits to the main program after programming complete. I got this working with AVRDUDE but found it would not work with eePe, which uses multiple AVRDUDE entries to save EEPROM and then burn. So I mod'ed the bootloader to stay in bootload continuous. When done you exit by powering down and then power back up for normal run. You have to load the bootloader first via ISP programming but after that you can just use the bootloader.

So now I program by pulling the DJT module out, and use an FTDI programmer connected to RX, TX, GND pins of the module connector without cracking the case open. I have to use FTI's FT_PROG utility to invert the TX/RX pins to make it compatible with my MAX3232 converter inputs. I've also done this wireless Bluetooth using an HC-06 adapter to prove to myself it works. For that I had to use another converter (ugh!) to invert but it works fine.

The pic shows my FTDI connector plugged into the module TX-RX lines. I'm powering the TX off the FTDI with the case still open for test (connected to my ISP Power and Ground connector pins. But I've also tested it using battery power and module TX-RX-GND connection only.

If interested, to use you would use ISP to set your M128 fuses using the txt file settings I attached below. Then program flash with the main.hex file attached. With the right hardware modes you are done. In eePe, make sure you set the -P COM port, -c AVR109 programmer, and -b 38400 flags in 'Options'. And off you go. I've included the source main.c if you are interested what the changes look like to the bootloader code.

Hope this helps someone.

Thanks,
George

[jhsa]

Later versions of Er9x for m128 already have a bootloader. To enter bootloader mode just start the radio with both horizontal trims pressed inwards.

I use a FTDI connected directly to the main programmer MISO, MOSI and GND lines.. no need to invert the FTDI. This is already TTL level. On the back of the radio is RS232 level as far as I know. No need to remove the RF module.

João

[MikeB]

See this thread: viewtopic.php?f=5&t=6525&hilit=bootloader+128

Mike.

[MGeo]

Oops , sorry about that. I did look at that thread (too) quickly and decided it was about the MegaSound board.

Oh well, I learned a bit about bootloaders and AVRDUDE in the process.

Best Regards,
George

[MikeB]

I have the bootloader running on the M64 as well, but the FrSky version is so nearly full I've chosen not to include it.

I've used the "Optiboot" code that I first used on the Megasound board. When I get a chance I shall try to get it on to the '2561 as well.

Rather than start in the bootloader, I've chosen to still start in the main application, but if I find both trim switches active I jump to the bootloader code.

Mike.