ATTINY23 chip heats way up

[crazybutable]

I've been using my USBtinyISP for years, and it has always worked great. Until today!

I made a homemade minimalist board out of an adafruit 1/2 size breadboard PCB. I plugged in my USBtinyISP and avrdude didn't recognize the chip. avrdude recognized the USBtinyISP and was talking to it (I got the "initialization failed, rc=-1" error).

I unplugged my circuit to quadruple check my wiring, and everything appeared to be okay. Then I hooked up power (but not the USBtinyISP!) to my minimalist board and started probing with a meter, and again, everything appeared to be okay. Then I smelled the magic smoke.

It wasn't coming from my circuit or my power supply. I was baffled, until I felt my USBtinyISP and it was quite warm. And smelly. And only connected to my computer via USB, NOT connected to my circuit at all. I quickly unplugged it from my computer, and tried to find the source of the smell and the heat. Turns out it was the ATTINY23.

Now, I wanted to make sure I wasn't going crazy. So I plugged it back in again real quick, and it appears to talk to the computer just fine. But it will not recognize any chip I hook up to it.

So, I'm assuming the ATTINY23 is toast. Should I worry about the rest of the USBtinyISP? Or just replace the ATTINY23?

[adafruit_support_bill]

It is possible that it was toasted by some transient or a momentary short. But I'd give the whole board a close inspection before plugging a new chip in.

[crazybutable]

I have an older one with a shift register, and I put all of the resistors in. Do I need to worry about any of those components?

I inspected the whole board but I don't see any charred or blackened parts or PCB areas.

[adafruit_support_bill]

If there is no obvious damage or visible evidence of a short, you should be OK.