so i ordered a 5 pack of attiny85 boards. I finally figured out how to upload a sketch. and i plugged the first board into my power source that i usually use for my nanos and my first attiny fried instantly. after research i found that these little boards are advertized with a voltage regulator but the vcc cant handle more than 5.5 volts. I think its silly that they bother having or advertizing a voltage regulator that can only reduce the voltage by half a volt.
anyways so i plugged board #2 into a regulated 5 volts and board 2 is also blown because i guess i should have used the vcc instead of the 5 volt pin.
so i had board #3 working... horray. but found that since pin number 5 is used for programming that the digital write doesnt put out the same voltage as the rest of the pins because its used for programming the thing. so anyways im not really sure if i burnt out board #3 because the voltages crossed when i plugged in the usb power while hooked to the progect power. or maybe because i have used set a programming pin to output that its just not detecting a signal to take a different sketch??? anyways, board 3 is dead too for whatever reason.
i have two boards left and thought i would ask for "do" and "dont" advice from the community before i blow up my last two boards????
over the last year i have had many different development boards and never fried one like this
thankfully these little things are really cheap. just wondering if they are useless as well
attinys are cheap boards but its appropriate because they do very little. if i am going to pay more i will buy nano's like before and never worry about this silliness
The LDO on those boards drops at least a volt, probably more like 1.5 minimum (dropout), so if feeding from Vin, you should be putting 6.5v or higher if you want 5v.
When you say it "fried" it, what do you mean?
Could you have hooked up the power backwards or something?
Connected the external power supply to 5v instead of Vin?
I'm pretty much certain that you are doing something horribly wrong to damage these boards. What I'm not sure, but these boards are not known for being easy to damage...
Pin 5 is the reset pin. On some digispark clones, they set RSTDSBL, which turns it into an I/O pin, but with very weak drivers, so it can't supply as much current as the other pins; this also prevents programming via ISP (but you can do it through the bootloader).
Have you considered just using bare ATTiny85's (on prototyping board, for example - I sell some nice protoboard, and even one specific for the tiny85) and programming it via ISP (using a USBAsp, for example)? Then you won't have the two pins used for programming constrained by the external parts mounted on it, and you'll get to use the full 8k of flash. For using ATTiny this way, you'd want to install the core linked in my sig.
I have a rather low opinion of the VUSB bootloader digispark clones. They seem to generate a lot of confusion and frustration here, and all the hardware associated with it constrains your design.
Of course, nanos and pro mini's are so cheap that it's hard to justify using anything else....
these boards are not known for being easy to damage...
thank you this is the info i was looking for.
i realize i did something wrong for the first two boards i ruined.
when i say "ruined" i mean that cute little sizzle sound we love followed by a tiny puff of smoke!!!
i learned the hard way! LOL.
now i am powering my new board ok.
Pin 5 is the reset pin. On some digispark clones, they set RSTDSBL, which turns it into an I/O pin, but with very weak drivers, so it can't supply as much current as the other pins; this also prevents programming via ISP (but you can do it through the bootloader).
so now i am down to two questions.
Can I still use pin 5 for an input without any issues?
if i have power plugged into the vcc. can i still plug it into the usb at the same time for programming?
seems one of these two things has rendered my third board useless. it will no longer take a sketch.
not sure if connecting vcc and usb power overloaded something or if maybe utilizing pin 5 is preventing communication with the usb connection. do any either of these theories make sense?
If you managed to get a sizzle and pop, you must have connected something very wrong.
I don't suppose you're able to see where the smoke came from, maybe locate a visibly damaged part? Look for hair-line cracks in IC/diodes, or scorch marks on the PCB.
On boards with RSTDSBL set, yes, you can use pin 5 as an input (I mean, you can use it as an output too if it doesn't need to source or sink much current - but IIRC it's output drivers are really weak). On board where RSTDSBL is not set, driving pin 5 low will reset the chip.
Plugging into USB while connected to external power should be fine - the board I have that looks like that does have the diode so the 5v from regulator can't feed back to the USB port...