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Topic: An Attiny85 I/O Network (Read 3 times) previous topic - next topic

dritchie0042

You guys are something else! Thanks for all the help. That's great to hear the reg. situation can be simplified.

Back to square one I suppose.

I've got one other question if you don't mind. As for programming the boards, it would cost far more in resources to make a dedicated "ISP programming board". Trying to cut down on my budget and overall costs, couldn't I just add a 2x5 pin shroud to each board and use the USBasp ISP programmer? (Haven't tried out that programmer yet.)

Maybe its just me, but I don't like using the Arduino to program Attinys. Switching out chips back and forth and whatnot.

strykeroz

If swapping out the microcontroller to program it bugs you, there's always the option of putting a 6 pin header on your board and programming them in-place too.  If you add a dedicated programming board, are you thinking that would just be a set of headers and some kind of switch to select the target uC to program?  If so that sounds like headers on each uC level would be cheaper/simpler to me, but entirely your call of course.

Cheers !
Geoff
"There is no problem so bad you can't make it worse"
- retired astronaut Chris Hadfield

GoForSmoke

If you have lots of them, why not set up a ZIF socket and ISP circuit on a breadboard?
Then your modules wouldn't need headers either.

Another thing to give you mileage would be to use SPI shift-registers to light the leds and 1 Tiny to send data to many daisy-chained shift registers. A Tiny running at 8 MHz can send SPI data at 1 MBps or less which allows longer SPI bus lines but still you could change 40 8-bit registers 20,000 times a second with cycles to spare for another 6,214... which would give time to communicate with other Tinys on the same SPI bus.

I wouldn't bother with boards for something so simple, there's another buck apiece for many pieces. I like sockets, you can plug leads (headers too?) in the holes as easily as chips and either solder to the legs or push them into connectors. They're cheap and even cheaper in quantity, and a few extra pins don't hurt do they?

Well anyway, that's just stray thoughts.


I find it harder to express logic in English than in Code.
Sometimes an example says more than many times as many words.

dritchie0042


If swapping out the microcontroller to program it bugs you, there's always the option of putting a 6 pin header on your board and programming them in-place too.  If you add a dedicated programming board, are you thinking that would just be a set of headers and some kind of switch to select the target uC to program?  If so that sounds like headers on each uC level would be cheaper/simpler to me, but entirely your call of course.

Cheers !
Geoff


I know what I said before, but things change as new ideas develop.

Now, I pretty sure I would like all the boards made equal. But they will still have all the functionality as before. 

I think that is possible with the USBasp. Cuts down on: costs, overall work, wires and frees up my Arduino. The most practical solution I can see is simply adding a few male pins for the 5x2 native USBasp connection.

To be honest, I'm very unsure. New territory for me. So your input is very much appreciated.

____

On a side note, one thing I forgot was 10k pull-down required between signals. AH, that is going to be hard to incorporate. Probably have to use a DIP switch.

strykeroz

There is no wrong way in this choice (at least I don't think there is).  I'm working on a small board now with ATTiny where I'll have 60 made up - the first 10 prototypes arrived tonight in fact.  The programming for this one is unlikely to be often, so I'm going for a socketed ATTiny to cater for those occasions rather than soldering 60 sets of headers.  Colour me lazy maybe  :)  In contrast, if you think these things will be programmed often I'd do what you're suggesting with the ICSP headers (or equivalent) for sure.

I've seen some designs using bare pads for the ICSP so a rig with pogo pins can be used for programming also.

It's good to see you're taking this one back on.  Do keep this thread updated.  Cheers !
Geoff
"There is no problem so bad you can't make it worse"
- retired astronaut Chris Hadfield

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