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Topic: How to turn ATTiny PB5 RESET and I/O pin into a regular I/O PIN? Changing RSTDIS (Read 3715 times) previous topic - next topic

alexe100

Hi
How can I change the RSTDISBL fuse bit in order to turno PB5 into a regular I/O pin? I am using arduino as ISP and I am programming using arduino approach

Thanks

johnwasser

Once you disable the RESET pin (to use it for I/O) you can no longer use an ISP programmer.

Might be time to invest in a High Voltage Parallel Programmer.
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alexe100

Oops, that is right, tiny85 Pin 1 is connected to UNO Pin D10.

Is it possible to program it with a avr dragon or ISP cable that come with STK300, after turning the RSTDIS fuse?

Tom Carpenter

You can't use ISP once you disable the reset pin, no matter what ISP programmer you get.

You require a High Voltage programmer.
~Tom~

baselsw

You can also make the following shield that turns a arduino to a high voltage programmer.. Here it is: http://mightyohm.com/blog/2008/09/arduino-based-avr-high-voltage-programmer/

Tom Carpenter

That link wouldn't really help much for an Attiny85. This would however:
http://www.rickety.us/2010/03/arduino-avr-high-voltage-serial-programmer/
~Tom~


baselsw


That link wouldn't really help much for an Attiny85. This would however:
http://www.rickety.us/2010/03/arduino-avr-high-voltage-serial-programmer/


Well my link describes how the project started etc.. If you read on you can see at the bottom that there is a link with an updated version like the one posted by hiduino which support t85 and t2313... You can't expect me to give the thread starter everything on a silver plate ;)..

john1993


You can't use ISP once you disable the reset pin, no matter what ISP programmer you get.

You require a High Voltage programmer.


or, as mentioned in the other thread, a tiny arduino bootloader which allows programming with reset pin as io and no 12v required.

Tom Carpenter

Bootloaders can also be used. But to go down that route you have to tune the internal oscillator and hope that it doesn't detune itself.

I modified a version of Optiboot to work properly with Attiny devices. The bootloader includes CodingBadly's TinyTuner sketch to allow you to tune the oscillator and have the tuned value be loaded automatically as part of the bootloader routines. Once the oscillator is tuned, the tinyTuner sketch code is deleted meaning the bootloader takes up only 576 bytes of flash.
The bootloaders can be found here:
https://github.com/TCWORLD/ATTinyCore/tree/master/tiny/bootloaders/optiboot
~Tom~

alexe100

Many thanks.
I dont know nothing of High Voltage programmers and I have to read about it...
But it seems there is other options (you wrote about) and so i have to study them too.
Thanks


fungus


Many thanks.
I dont know nothing of High Voltage programmers and I have to read about it...


They don't work with the Arduino IDE.
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

fungus



You can't use ISP once you disable the reset pin, no matter what ISP programmer you get.

You require a High Voltage programmer.


or, as mentioned in the other thread, a tiny arduino bootloader which allows programming with reset pin as io and no 12v required.


Doesn't that mean you just have to reserve a different pin for the bootloader, making it moot?

No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

Docedison

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"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

Tom Carpenter



Doesn't that mean you just have to reserve a different pin for the bootloader, making it moot?


Nope, just add jumpers. That way you can disconnect the jumpers when programming, and reconnect them when done. I've used an Attiny85 this way before, it works quite well.

Also, if the pins chosen are ones used as outputs then depending on the applications you can probably get rid of the jumpers.

But if you think about it, if you need a HVP, then you would need to be able to isolate all 5 pins in order to program it. For a bootloader you only have to be able to isolate 2.

If you are using a DIP package it doesn't matter as you can simply pull the chip, program it, and then plug it back in.
~Tom~

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