Mikael Ulfenborg

If anyone is interested: I've tested all digital input/output and the ADC and everything works. The only glitch was that the pins for UART1 were configured for serial communication. Next step was to test TWI/I2C and this does not work. I've compared the 328p and the 1248p and they are the same. Even different AI-chats (they sometimes have a hard time with Forth, but thats ok with me :) ) agree with me, it should work. When I inspect a simple i2c.ping with a logic analyzer the CLK-signal generates...

It looks like the full swing oscillator did the trick. I thought i had tried that but obviously not... Big thanks for the time you've invested in this!

I've done some more testing and have "reliable" boot after reset with "E FlashForth 5 ATmega1284 05.03.2026" displaying each time. Here's an example of output with a few key press from me: FlashForth 5 ATmega1284p 05.03.2026 � ? ok<#,ram> after that it is non responsive I got it to work TWO TIMES and tried "words" and a few calculations, all working perfectly. Electrically the chip sits on a breadboard with decoupled +5V from the FTDI. As I said before the setup works with a 328p. Fuses are: LOW:...

I use UART0 (pins 14=RXD0, 15=TXD0). I also use the "same" breadboard setup (obviously with shifted pins) for an 328p and it works. I will check all connections (for the umpht time) later today.

Hello and thank you for your time! It sort of works, it boots with the message: E FlashForth 5 ATmega1284p 05.03.2026 But then it stops. I've tried several methods of programming the chip (TL866II+ ZIF and ICSP) and avrdude through an usbasp. The latter feels more robust. I've also tried to power it with both external 5V and with the FTDI adapter. The only thing I can think of is the fuses. I've (sort of) read the documentation and concluded it should be the same as the 328p. As this is only an hobby...

Hello! Is there any documentation for how to compile for the Atmega 1284p? I've found one in my component storage and it would be nice to test this chip. I'm used to electronics and programming but I have no experience with compiling for Atmega processors (and quite rusty when it comes to assembler)