support Arduino Mega / stk500v2 protocol

[tve]

Currently none of the flashing options work for the mega with the stk500v2 protocol. It's not clear why nothing works, so some logic analyzer work is required...

[jcw]

Different baud rate, perhaps?

[ykri]

Might help your investigation, I tried this with Mega:

1. Installed MCU bootloader -> uploaded OTA with esp-link -> SUCCESS!!
2. uploaded OTA with esp-link -> FAILURE!!

i.e. it uploads ok after a fresh bootloader but then any subsequent upload fails.
It's like the first upload meshes up with the bootloader???
Any subsequent upload can succeed only by manually pressing MCU RESET and only at port 23.

[Xerxes3rd]

This sounds like an electrical problem- like the board isn't resetting at all or isn't resetting when the software thinks it is. See this post on the arduino forums for more information, noting that the symptoms described in the post are very similar to this issue (resetting and programming works fine with a 328/Uno but not a 2560/Mega):

http://forum.arduino.cc/index.php?topic=310109.0

[bestbuddyrohit]

hi,
Any update with atmega2560. i also experienced the same. i i press the reset button i have a bit chance that mcu is programmed. but yes if the chip is freshly loaded with the boot loader, it will program at once without external reset required. after that same behaviour.

[Grtschnk]

Remark: I used the -D flag, but I'm not so sure if this is completely kosher. Flashing without -D flag gives: avrdude: stk500v2_command(): command failed

Found a quick fix for my Arduino Mega clone (equipped with CH340 Usb to Serial)! Don't know if it will work with a "proper" Mega

One way:

1. avrdude -p m2560 -c stk500v2 -P net:192.168.0.27:23 -b 115200 -U flash:w:yourhex.hex -D
   It won't work anyway but now you can access it via ArrowUp in your console window
2. Try: avrdude -p m2560 -c stk500v2 -P net:192.168.0.27:2323 -b 115200 -U flash:w:yourhex.hex -D
   ..and wait for the first timeout (after all it might work on the first try?)
3. Ctr+C (abort sequence) The next command must follow immidietally!
4. avrdude -p m2560 -c stk500v2 -P net:192.168.0.27:23 -b 115200 -U flash:w:yourhex.hex -D
   (to be fast you hit ArrowUp twice and then return in your console)

Other way:
Hit the reset uC button in ESP-link and quickly follow step 4.

What happened? My theory (I'm certain someone with more knowledge might have a better explanation): The Mega needs the stk500v2 protocol, but ESP-Link doesn't detect it as a flashing sequence and doesn't reset the MCU. Using port 2323 in step 2 forces a reset of the MCU. Unfortunately it doesn't work immediately, maybe timing issues? By aborting (via Ctr+C) and immediately using the command with port 23 we just forward the flashing sequence from avrdude. Basically it is like hitting the reset button by hand - only remote.

Found this out while experimenting without the connected reset line first and noticed that manually hitting the button sometimes worked. After an hour or two I got the timing right most of the time 😆

My clone board has an LED that's on when it is in flash mode. Sometimes ESP-link manages to set it into flash mode via -c arduino, but then it just hangs at the "not in sync" error. (I read somewhere that the Mega only supports the stk500v2 bootloader // wiring works too with this method!)

A possible "proper" fix might be (just speculating) to change the delay time between reset and start of communication when using port 2323. Might mess up flashing of other chips, so it should be user configurable in the UI.

[dannybackx]

This issue is bothering me. Can anyone tell me where to look to debug/fix this ?

[tve]

I think the first step is probably to read up which char sequence starts the programming and add it to esp-link: https://github.com/jeelabs/esp-link/blob/master/serial/serbridge.c#L169-L182
The second step is probably to look at the TX and RX lines with a scope and see what the timing looks like, I hope the Mega responds with something similar to the way the 328p does....

[janchrillesen]

One thing I noticed is that I can't program my Mega2560 over USB when the ESP8266 is connected. I have two Mega2560 with ESP8266/ESP-link connected to a prototype cape.

One board is using a simple voltage divider on the Mega2560 TX line towards the ESP8266 and TX of the ESP8266 directly connected to the Mega2560 RX. On this cape I need to remove the ESP8266 to program using USB
The other board is using "real" (MOSFET based) levelshifters on both RX and TX lines and on this board I need to remove the entire cape - so it seems like there may be some hardware level stuff stopping programming from working.

Does anyone else see this issue?

[dannybackx]

@tve If I understand this correctly, the Mega programmer sends a sequence which esplink needs to intercept, put the Mega in programming mode, and only then get avrdude and the Mega to talk to each other ?

When I run
avrdude -patmega2560 -cwiring -t -Pnet:esplink:23 -x snooze=1 -v -v -v -v
it says [...]
avrdude: Send: . [1b] . [01] . [00] . [01] . [0e] . [01] . [14]
avrdude: ser_recv(): programmer is not responding
avrdude: stk500v2_ReceiveMessage(): timeout

So I'm guessing I need this sequence in serial/serbridge.c like
|| (len == 7 && data[0] == 0x1b && data[1] == 0x01 && data[2] == 0x00
&& data[3] == 0x01 && data[4] == 0x0e && data[5] == 0x01 && data[6] == 0x14)
and then I should see the reset sequence being triggered as
59746> SERBRIDGE Accept port 23, conn=0x3fff9828, pool slot 0, ix 0, mode 0
59747> SERBRIDGE Accept conns 0x3fff9828 0x00000000 0x00000000 0x00000000
59801> SERBRIDGE Accept ports 0x3fff6fb4 0x3fff6fd0
60050> MCU Reset=gpio5 ISP=gpio-1

[tve]

If the reset sync sequence is really that long, yes. You could also start with just matching the first 3 chars, for example.

…

On 12/11/2016 1:36 AM, dannybackx wrote: @tve <https://github.com/tve> If I understand this correctly, the Mega programmer sends a sequence which esplink needs to intercept, put the Mega in programming mode, and only then get avrdude and the Mega to talk to each other ? When I run avrdude -patmega2560 -cwiring -t -Pnet:esplink:23 -x snooze=1 -v -v -v -v it says [...] avrdude: Send: . [1b] . [01] . [00] . [01] . [0e] . [01] . [14] avrdude: ser_recv(): programmer is not responding avrdude: stk500v2_ReceiveMessage(): timeout So I'm guessing I need this sequence in serial/serbridge.c like || (len == 7 && data[0] == 0x1b && data[1] == 0x01 && data[2] == 0x00 && data[3] == 0x01 && data[4] == 0x0e && data[5] == 0x01 && data[6] == 0x14) and then I should see the reset sequence being triggered as 59746> SERBRIDGE Accept port 23, conn=0x3fff9828, pool slot 0, ix 0, mode 0 59747> SERBRIDGE Accept conns 0x3fff9828 0x00000000 0x00000000 0x00000000 59801> SERBRIDGE Accept ports 0x3fff6fb4 0x3fff6fd0 60050> MCU Reset=gpio5 ISP=gpio-1 — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#87 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AACaOJxvwX5K5p5zoWF58kK1oAeM7weyks5rG8QSgaJpZM4G9fKr>.

[FernandoGarcia]

Hi @tve !

I don't know if it's possible or how to make but I would like to give this suggestion.

I have tested this library with an Arduino nano and worked very well. I'll try with Arduino Mega later.

https://github.com/esp8266/Arduino/tree/master/libraries/ESP8266AVRISP

Maybe you could join this library to ESP-link to make possible programming via ISP instead UART.

With ISP is possible burn hex file to any type of Arduino.

Best regards.