Uploading to ATtiny1626

[hmeijdam]

I hooked it up like you have with the 330R and said adapter and it works just fine. I see you power you MCU from the breadboard and not from the FTDI.

So tried that also and with the jumper on the FTDI on 5V and 3V, both work. The only way I can replicate your error is when I remove the voltage selection jumper from the FTDI board completely.

[BitSeeker]

Thank you for your time in replicating the setup. Your result is interesting. I used a 330ohm since I didn't have a 470ohm, but I figured its not that critical. I am not sure, but I think its there to protect both devices by preventing the possibility of a short on one affecting the other.

I also checked using a DMM to make sure the adapter was making good contact with the chip pins and the resistor to the UPDI pin on the breadboard and it was. The breadboard is new, but I had nevertheless wiggled the individual components just in case there was a bad contact somewhere. After reading your comment confirming that the setup does work, there was only one thing left to try. As it happens, I knew I had another one of those FTDI breakout boards somewhere and in the event had a couple of other types I could try. I found the FTDI one this morning and swapped out the one on the breadboard and then tried again. This time it worked on the first attempt! Evidently, there is some problem with that first FTDI breakout board. Incidentally, I also did a test with each diode and it works with either of them.

Now that I have uploaded my sketch, I also have a response from the UART on pins PB2 and PB3.

One thing I am not sure of though, is how the pin designations work? For example, PA7 is not defined, so what pin number is it? What pin numbers are assigned to the other pins?

[hmeijdam]

I always use the direct pin name assignments

blink example:

#define LED PIN_PA7

void setup() {
  pinMode(LED, OUTPUT);
}

void loop() {
  digitalWrite(LED, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(LED, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);                       // wait for a second
}

You may want to read the how to refer to pins

[BitSeeker]

@hmeijdam

#define LED PIN_PA7

Ah, OK, so not 7 or PA7 (the latter as used in MPXLAB), but PIN_PA7. Got it. Thanks.

Had a look at the non-working FTDI board under the microscope. Looks like there was a tiny metallic splinter stuck in the flux between the RX track and one of the pins to which the voltage jumper is connected that was shorting them together. I cleared the flux and the board now seems work as it is supposed to.

Thank you for your help.