first of all I want to thank you in advance for your help. I want also to apologyze about my english because I'm not not an english speaker.
My name is Javier and I'm having an issue with one board I've designed for a project. I'm using an Attiny45V SOP8 to drive some high power LED's. My board is working fine but I'm struggling a lot to upload the sketch into the Attiny using an Arduino as ISP (I have 10uF cap between GND and RESET pin on the Arduino ISP)
I'm having the following issue:
avrdude: Device signature = 0x000000
avrdude: Yikes! Invalid device signature.
The point is that I can proggram the chip without issues when it's alone and is not soldered into the board, but once is soldered I cannot proggram it. This makes me to think that has to be something related to the schematic design of the circuit. I'm attaching the schematic to see if anyone can point me out what can be the issue.
Don't program the chip in-circuit. Program it before you solder or modify the board to allow complete isolation while programming (maybe by solder bridges or the like). You have rather strong pull-downs which are stronger than internal pull-ups of the UNO.
many thanks pylon and jremington for your answers.
I can do it, but nom i'm in prototyping phase so I will need to adjust some code when testing. That's why I need to be able to program it while assembled in the PCB.
Let me try to explain what I've tested today. I've soldered small cables directly to the Attiny pins and I get rid of the "invalid signature" error and seemed started working but when avrdude started to verify, it ended with "content mismatch" error.
Then I've found the following. I was trying to connect my oscilloscope to the circuit and as soon as I connect the GND of the probe to the circuit GND, it worked fine. I could upload the sketch without any issue. Then I've observed that there was a lot of noise on the GND supply comming from the Arduino. After that I've isolated the power supply from Arduino from the circuit using an external PS and it worked perfectly.
My brain cannot understand what is going on. Seems something related to noise, but I cannot understand.
What do the arrows pointing to P1, P2 etc go to?
How was the Tiny being supplied VCC previously?
What voltage do you see at the VCC pin of the Tiny when you are programming? And also please scope the signals at the programming pins.
Without a complete wiring diagram of your entire setup, and a description of what you have observed, it is impossible to say what the root of the problem is, other than "faulty wiring".
If I supply the Attiny from the +5V and GND from the Arduino and the arduino is powered from USB's, I cannot program it.
But if the Attiny is powered independently from another PS, I can program it without any issue.
I will do, I wanted to scope the signals when programming and that's how I found the issue when connected the GND from the scope.
Seems like too high a power draw from the rest of the circuit when powered solely by the Arduino.
Do please let us know when you are able to check the voltages and current draw.
And as jremington said above, posting the wiring diagram of your full setup (programmer Arduino, ATTiny, power sully, USB, anything else in the circuit) will really help
