Identify/programm Attiny on tamiya rc light controller

Projects General Guidance
1

Hello together,

I am currently trying to reprogram a purpose build, cheap, tamiya rc led controller.

It takes 3 PWM channels as input and then switches 6 LED channels on/off depending on logic.
I do not really like the integrated logic.

So I opened it up and found an unmarked iC. Tracing and measuring the different pins, I am pretty sure that this is some kind of Attiny board.

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  • Pin 4 seems to be reset, tied to VCC to block a reset.
  • Pin 11 is tied to GND, dont know why?
  • The LEDs are sink driven

I disconnected Pin 4 from VCC and was able to reset the board with it. Visible becasue the rythmic blinking of the LED does reset and start from the beginning when I pull it to ground.

From the rest of the pinout it looks like a attiny 44/84. But I am not able to read the signature.

I tried with avrdude using an ArduinoISP2 and a CH341a.
I also tried using NPN Resistor with 12 V source to do a high voltage reset.

But whatever I try I do not get a valid signature. (00 00 00).

Maybe I am wrong with my Attiny assumption? Maybe someone have some more insight?

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If all fails, I might just replace the controller.

Thanks in advance, best regards

2

Probably the easiest solution. Build your own with an ATtiny.

3

Short update here, I tried TPI programming with an Arduino nano real quick.

But so far I was not successful in getting a sigbature. But it seems the controller switches in a different mode when being reset by the tpi programmer, so maybe I am on the right track.