Advanced Search

All looks great! And tweaking bootloader sweet as it gets, thanks.
I did try editing bootloader graphics. Best I could do was either remove all graphics and replace with just just random pixels..... So pointless for me.

In regards copper logo + less. I just etched some copper foil and stuck that on back piezo grp board, then soldered smd to that. But driving off piezo sounds a much better idea.

You will find more RCGroups diy electronics / flashy rx both of them.

In the links section on the left. there is now a link to all of the bootloaders I have (including the devo7e_256 variant). I also added all of the legacy firmware files I have since Walkera is making it difficult to locate them these days

Well, after many hours of effort, I was able to hack the 7e bootloader to support 256k Flash.
It turns out that the RAM initialization is compressed in the bootloader. This makes it difficult to search for strings. My guess is that this is not some sort of encryption/obfuscation, but instead is a capability of the compiler when aggressive optimizations are enabled.
The compression scheme is simple, it basically has 3 modes:
1) copy from ROM to RAM
2) zero bytes in RAM
3) copy from RAM to RAM

The trick was to find a sequence which decoded the same way and used the same number of bytes (since there is no way to change the size of the byte array). I got lucky, and found that by changing the right 3 bytes, I could change the memory size from 116k to 244k. I then verified that I could use the new bootloader to upload an image >128k in size, and everything worked.

So my 7e is now back in business I have the 'ultimate' firmware built, but I forgot to enable the ADC for the pots, so while they show in the menu, they don't actually work yet. I'll fix that tomorrow, but for now I'm done for tonight.

PhracturedBlue wrote: I want to reiterate that adding analog dials without also upgrading the MCU may not work. I am not sure if there is extra room in the code. The custom version of Deviation I'm building to add the extra dials will hard code the number of analog inputs, and will only support the 256k MCU

Today I ran into another problem. Since my 'Ultimate 7e' is complete (for now) I tried to install the custom firmware on it. Unfortuantely, I forgot that the devo7e bootloader identifies the chip capabilities. Specifically, that the chip only has 128kB of ROM. I have tried to hack the bootloader, but I've been unable to find the code I'm looking for. I've tried installing a custom dfu bootloader, but so far no luck either. So I'm still working on enabling my 'ultimate' 7e...

To replace the MCU, it should be very complex task I guess ....

I want to reiterate that adding analog dials without also upgrading the MCU may not work. I am not sure if there is extra room in the code. The custom version of Deviation I'm building to add the extra dials will hard code the number of analog inputs, and will only support the 256k MCU

Today I ran into another problem. Since my 'Ultimate 7e' is complete (for now) I tried to install the custom firmware on it. Unfortuantely, I forgot that the devo7e bootloader identifies the chip capabilities. Specifically, that the chip only has 128kB of ROM. I have tried to hack the bootloader, but I've been unable to find the code I'm looking for. I've tried installing a custom dfu bootloader, but so far no luck either. So I'm still working on enabling my 'ultimate' 7e...

Well, I finished the hardware mods for now.
I've added the 2 SPDT switches, along with 2 analog POTs. I don't have a UniversalTx board ready yet, so that'll have to wait. Figuring out how to connect to the analog pins took a lot longer than it should have. I stupidly thought it would be easier to do with the hot-air gun. I also thought using my #45 AWG wire would make it easier. After a lot of trying different things, I found a technique that was pretty easy:

1) using a medium ball-tip iron (~ same width as the MCU pins) add extra solder to the MCU pins in question (but don't bridge them)
2) strip about 1 to 2mm off of some #34 AWG magnet wire (soldering iron works well for this)
3) bend tip of wire at 45-degree angle
4) using microscope, get wire close to MCU. touch iron to MCU pin, and touch magnet wire to MCU pin. remove iron and hold until cool.
5) Add hot-glue to hold magnet wire in place (I actually reheated the hot glue with my hot-air gun to get better adhesion

It isn't much fun, but the connection is good, and there are no shorts.

Here are some images of the inside of my box. Taking good pictures of the magnet wire connections is beyond my ability. The box is getting a little crowded too.





I haven't done the software programming needed to enable everything yet. I am not sure if the analog dials can be supported via hardware.ini. the 7e is so tight on space, I am not sure if there is room for the additional logic.

I can't post the 7e bootloader, but PM me, and I can point you in the right direction.

I'm on to replace the MCU on my second devo7E, but where can I download the bootloader ?

The link below only explains how to do it.

Thank you.

PhracturedBlue wrote: That is unlikely. The number of users willing to do this mod would be really small. If you are capable of upgrading the MCU, then you are capable of installing the build system and building the update

Note to anyone considering this: It isn't as easy as just replacing the MCU. You also need a way to install the bootloader. I use a STLink/V2 (~ $25). You can get chinese no-name SWD programmers for ~$10 from ebay though.

It isn't hard; I just documented the procedure here:
www.deviationtx.com/forum/6-general-disc...-7e-bootloader#34250
But it is an additional expense.

Cereal_Killer wrote: Well I thought I had the programmer needed, till you said "20 pin header", I have one of the $5 Chinese "ST-Link V2 mini emulators" that I bought and use for bradwii, will that do the job?

Thats the one your good to go.

Well I thought I had the programmer needed, till you said "20 pin header", I have one of the $5 Chinese "ST-Link V2 mini emulators" that I bought and use for bradwii, will that do the job?

PhracturedBlue wrote: That is unlikely. The number of users willing to do this mod would be really small. If you are capable of upgrading the MCU, then you are capable of installing the build system and building the update

Note to anyone considering this: It isn't as easy as just replacing the MCU. You also need a way to install the bootloader. I use a STLink/V2 (~ $25). You can get chinese no-name SWD programmers for ~$10 from ebay though.

I'm more than capable of the soldering, that's simple [for me, yes even 44pin TQFP and QFN's!] but I have yet to complete building from source. I've tried several times, I've got everything needed (as well as your new MinGW stuff) yet I've still not got threw the process... Admittedly I'm not devoting much of my time to learning, it's something I've currently been putting off cause I'm happy with the nightlies... I really hope that you'll (and the other contributors) will be willing to put our releases for this for people like me!!! As you may have saw I'm waiting on parts for add-on POT's for the 7E via PPM but if the new MCU would allow direct analog input's that's be amazing and I'd pretty much just stop work and devote that time to trying to help out on this.


Thanks man, really really excited about this!

RoGuE_StreaK wrote:

PhracturedBlue wrote: 1) Replace the MCU with a STM32F103RCT6. This will give my 7e 256k FLASH and 48K RAM (smae as a devo10)

Is this the one? ebay US$2.10 shipped

That s the one.

racemaniac wrote: If we can get official builds for devo 7e modded with the stronger mcu, i would definitely upgrade mine too . Sounds like an awesome mod to make .

That is unlikely. The number of users willing to do this mod would be really small. If you are capable of upgrading the MCU, then you are capable of installing the build system and building the update

Note to anyone considering this: It isn't as easy as just replacing the MCU. You also need a way to install the bootloader. I use a STLink/V2 (~ $25). You can get chinese no-name SWD programmers for ~$10 from ebay though.

It isn't hard; I just documented the procedure here:
www.deviationtx.com/forum/6-general-disc...-7e-bootloader#34250
But it is an additional expense.

It turns out I had to do this today, so I can be pretty specific.
1st you need an stlink-v2 and a copy of the devo7e bootloader

You'll be using the 20pin header on the stlink.
on the 7e board, there is a 5-pin unpopulated header below the MCU, one pin is labeled RESET. We;ll call this pin '1'
connect pin1 (reset) on the Tx to pin 15 (NRST) on the stlink
connect pin2 (tms) on the Tx to pin 7 (TMS) on the stlink
connect pin3 (tck) on the Tx to pin 9 (TCK) on the stlink
connect pin4 (GND) on the Tx to pin 20 (GND) on the stlink
connect pin5 (Vdd) on the Tx to pin 1 (Vcc) on the stlink

just above the 5-pin header is a 2-pin unpopulated header. this is BOOT0. you need to place a jumper between the 2 pins.
On the upper left of the 7e circuit board is another 2-pin unpopulated header. This is power bypass. You'll need to short these together too, but not yet.

You need to install the software for the stlink-v2 to your PC (Windows only)

Now, plug in the st-link to the PC. It should be detected and drivers installed
Startthe ST-Link software.

make sure there are batteries in the Devo7e, and apply the jumper across the power bypass.

Now press the connect button in the stlink software on the PC. It should connect. If you get an error message, you have a connection wrong somewhere.

You will need to do a bulk-erase of the chip 1st. then you can load the bootloader and do a program&verify.
your bootloader is now loaded.

You need to disconnect the jumper on BOOT0 and power bypass before you do anything else.

Is there a more detailed writeup of the process, items and files necessary?

I'm good with a soldering iron, etc. Not much knowledge of the processor in the Devo. Done Arduino and others.


Thanks

PhracturedBlue wrote: What did you do that itis necessary?

I don't have a great description, but if you have a SWD debugger/programmer (STLink/V2) , you can install the bootloader by adding jumpers to the boot0 and power-override pads (the only 2-pin 0.1" pads on the board), and then using the STLink sftware to install the bin at 0x08000000

Do as above but also load again at 0x08003000 And this bit is important don't erase memory for second flash!
It does work, honestly.

Thanks. Tried that several times. No life.

Try pulling the battery for 15 seconds. That"s generally enough.

Thanks. Don't know what happened. Was attempting to load Deviation via Linux. Got lots of error messages. Then the thing died. No lights, no nothing. Perhaps it's something worse than a trashed bootloader. Will see.

What did you do that itis necessary?

I don't have a great description, but if you have a SWD debugger/programmer (STLink/V2) , you can install the bootloader by adding jumpers to the boot0 and power-override pads (the only 2-pin 0.1" pads on the board), and then using the STLink sftware to install the bin at 0x08000000

Can someone point me to a good description of how to re-flash the Devo 7e bootloader?


Thanks!

the stm32f072 is actually quite limited as far as I/O goes. It also does not have a hardware divider. It is really not very well suited to use as a base for a DIY transmitter. The primary advantage of this chip is the USB bootloader without need of an external xtal. Otherwise use an STM32F1 or F2 with a 12MHz crystal

Getting Deviation to run on any STM32 board with sufficient ROM/RAM should not be too difficult, though I'm not aware of anyone having done so as yet.