I've just acquired a new ATtiny84a-PU from Newark. I went to program it with an Arduino Duemilanove, had some trouble, but eventually got it to work. I can burn a bootloader and upload a program with the Arduino as ISP, but when I tried to upload the Blink sketch, the program uploaded but nothing happened on pin 0 (before anybody asks, yes, I did change the pin in the program from 13 to 0).
Poking around with the multimeter, I can see that I have a full 5 volts to the Vcc pin, 4.8-ish volts on the reset pin, and 0.6 volts on on the other pins... except pin 0. On pin 0, I see exactly 0 volts. Messing with the program, I can see that whatever pin I set the mode as output, 0 volts is shown between it and ground. I've done some looking around on the internet, but can't find anybody with the same problem as me.
Am I missing something about how to use this chip? Is the software wrong? Is there some easy electrical fix? Or is there not any fix and the chip is dead? I really have no idea. Any help would be greatly appreciated.
What hardware package are you using to add support to the Arduino IDE for the ATtiny?
pert:
What hardware package are you using to add support to the Arduino IDE for the ATtiny?
I was wondering about that too.
The tiny84 core provided on DrAzzy's site has a different pin-mapping to the most recent one by David Mellis.
Using the latest David Mellis core, D0 is physical pin 13, whereas DrAzzy's core maps D0 to physical pin 2.
(It had me scratching my head for a while - I use DrAzzy's tiny cores.)
The earlier version of David Mellis' core is the same as DrAzzy's.
Both map D5 to physical pin 8, but all the other digital pins are different.
OldSteve:
The tiny84 core provided on DrAzzy's site has a different pin-mapping to the most recent one by David Mellis.
DrAzzy recently added support for the damellis/attiny pin mapping to ATTinyCore: Add menu option for pin mapping on x4 · SpenceKonde/ATTinyCore@9198b98 · GitHub
pert:
DrAzzy recently added support for the damellis/attiny pin mapping to ATTinyCore: Add menu option for pin mapping on x4 · SpenceKonde/ATTinyCore@9198b98 · GitHub
Thanks for the heads-up, pert. I'll have to upgrade.
I see that he's now merged the Modern core with the main one too. I'll wait until it's available via the Boards Manager, then change over to the new version.
Thanks - yeah. That would be my recommendation.
1.1.0 board manager release is waiting on #50 and #47.
DrAzzy:
Thanks - yeah. That would be my recommendation.1.1.0 board manager release is waiting on #50 and #47.
Excellent. Thanks DrAzzy. I'm more than happy to wait. For my own stuff, I'm sticking to the pin mappings I'm used to from your earlier release. The reversed ones will be good for testing other people's code though.
I appreciate the effort you've put in lately improving your cores, by the way.
I'm using the 'attiny' by David A. Mellis library. I don't really think it matters though, since I can see with a multimeter what pins I select to be outputs. It's just that they don't change voltages when the program says they should. Is there some bug with that library?
I'll try DrAzzy's library today and see if that works.
GravelPunch:
Is there some bug with that library?
Well the reason I asked is that you're using ATtiny84A and I was wondering if that could be the cause of the problem(does the core support ATtiny84 only?). I don't know if it matters.
Tried Dr Azzy's library. The pin mapping was slightly different, but I'm still seeing the same behavior.
This is weird. I would think that if the chip was dead, I wouldn't be able to upload to it. But I'm still not seeing any activity on any of the pins.
84 and 84a are binary compatible. I've always used 84a.
Do other pins work?
GravelPunch:
I can burn a bootloader and upload a program with the Arduino as ISP, but when I tried to upload the Blink sketch, the program uploaded but nothing happened on pin 0 (before anybody asks, yes, I did change the pin in the program from 13 to 0).
What Pin on what PORT are you using?
GravelPunch:
Poking around with the multimeter, I can see that I have a full 5 volts to the Vcc pin, 4.8-ish volts on the reset pin, and 0.6 volts on on the other pins... except pin 0. On pin 0, I see exactly 0 volts. Messing with the program, I can see that whatever pin I set the mode as output, 0 volts is shown between it and ground.
What is the physical pin you are testing?
I have not seen that happen. I am using the ATtiny core that comes with 1.6.7. I use one of my Arduinos as ISP to program my Tinys and not having a problem.
Anyway I loaded the Blink default sketch and uploaded to a ATtiny84A I have and I get the blinking on physical pin 13 which according to the pin layout is PORTA PIN0. I am seeing a small voltage on that pin. And that is with delay(1000).
Hope that helps. 