cannot burn atmega1284 PU (Mightycore)

Greetings,
I’m trying to burn -unsuccessfully- ATMega 1284 PU , DIP 40.
System: Ubuntu 16.04
Arduino IDE: 1.8.9 (64 bit)

The are the steps I’m following:

  1. I followed these instructions and schematic about ATMega1284 wiring

  2. As suggested, I added the ATmega 1284 board inserting the URL: “https://mcudude.github.io/MightyCore/package_MCUdude_MightyCore_index.json” in my Arduino IDE/preference. This was succesful as I could find the target board in Tools->Board after installing the mighty core boards.

  3. As suggested, I left unaltered all the default parameters:

  • BOD: 2.7V (max low level voltage)
  • Standard pinout for Mightycore
  • Variant: 1284P
  1. I compiled and uploaded in my Arduino UNO the sketch “ArduinoISP”

  2. In Tool/Programmer I selected “Arduino as ISP”

  3. I burned the bootloader, but obtained the error "
    avrdude: stk500_initialize(): (b) protocol error, expect=0x10, resp=0x01
    avrdude: initialization failed, rc=-1
    Double check connections and try again, or use -F to override
    this check."

The complete error message is in the attachment.

Thanks.

error.txt (3.34 KB)

Try connecting a 10 uF capacitor between the reset and ground pins on the board you're using as an Arduino as ISP.

I added the cap as suggested.
Again an error, but the log is slightly different:
“avrdude: Device signature = 0x1e9706 (probably m1284)
avrdude: Expected signature for ATmega1284P is 1E 97 05
Double check chip, or use -F to override this check.”

In attachment the complete log.

UPDATE: I tried right now to change the VARIANT field in Tools: I switched from 1284P to 1284.
The operation seemed to go ok! Now I’ll try some test to see if I manage to upload some sketch on the board!

error2.txt (3.16 KB)

That's progress! The problem is that the default setting is for the ATmega1284P, but you have the ATmega1284.

You just need to select Tools > Variant > 1284

pert: That's progress! The problem is that the default setting is for the ATmega1284P, but you have the ATmega1284.

You just need to select Tools > Variant > 1284

Yep. I'm not an expert, on the chip I can read: ATMEL ATMEGA 1284 PU 1708

I errouneously thought "PU" was for variant "P"

[UPDATE]: I can confirm that it works. After burning the bootloader, I successfully uploaded on 1284 a simple sketch where I tested serial communication, analogRead(), alalogWrite(), digitalWrite etc...

In the Atmel days, ATmega1284-PU was the model of the DIP-40 package of the ATmega1284 chip. The equivalent ATmega1284P is ATmega1284P-PU. The TQFP surface mount package version is ATmega1284-AU and the VQFN surface mount package is ATmega1284-MU.

I think Microchip modified how things are labeled a bit after they bought out Atmel. I'm not recalling specifics of how things were changed though. All my chips are from back in the Atmel days.