At what point of the design process do you commit to buying the hardware?

[charliex]

So I'm curious at what point do people making large runs of products (but not like we own our own fab size, say in the 1000+ board range), commit to buying the parts?

I made a board on parts that were available, I made a few cnc'd boards, did a test fit, got the quotes etc. then the CPU went out of stock everywhere, so i recoded the firmware to be half the size so it'd fit on a smaller part that was available.

Of course the moment i'm ready, the second CPU goes out of stock everywhere. Then the AT45DB chip i'm using also goes out of stock..

I wanted to make sure everything worked correctly, that the board fitted, made sense, that it worked and tested out ok.

I just cannot source the parts anywhere, and the lead times seem to be largely just made up, since they haven't really changed or gotten worse since i started looking worldwide.

So what approach do you take ? Where do you commit to the hardware.

Hopefully this semiconductor shortage gets over with soon, but i'm really against the idea of using anything from Atmel in the future, since all three chips are Atmel parts, and i've noted a few other people saying they've had problems sourcing AVR's

At this point i may have to switch to another CPU and new PCB, which basically means starting from scratch.

[mikeselectricstuff]

Leadtimes are getting a bit tricky nowadays, so the only way to guarantee production is to buy all critical parts as soon as you know they will do the job, or design in something that is showing plenty of stock everywhere.
And of course wherever possible make provision for alternate parts, different packages etc.

[EEVblog]

Damn, which Atmel parts were they?
I've just speced in an ATtiny48...

Dave.

[charliex]

AT90CAN128-16AU, replaced with an AT90CAN64, then the AT45DB32 SU, been unable to find the 16 and 8 ,but 8 is really pushing it, the other guys were looking for Mega's i believe. I've searched high and low, a few days ago one place had 1,700 of the 64's in stock, next day 0.

I know its an older part, but theres nothing i've seen about Atmel EOL'ing it. They still list it as a viable part, same for the AT45's

Im looking at using an ARM to replace it, since they seem like they're more easily available.

Still if anyone see's them in decent quantities, i'd appreciate a nod.

[DavidDLC]

I have had some issues like you, that today pretty much I buy the hardware at the very beginning, and from there continue the project.

[charliex]

Yeah i just wasn't sure about the scratch design, and it got changed along the to add the external memory.

Still i suppose if i bought 1000+ cpus i could resell em since no one has any, hopefully its not because no one wants any.

Ahh the joys of hardware

[DavidDLC]

I didn't totally understand the question.

Yes for large quantities is not what I posted before.

[TheDirty]

As a low volume buyer there's just not that much we can do.  Had this issue with MSP430's in the last year.

[charliex]

Yeah i'm hosed unless i find some stock somewhere, or just hope the lead times are fairy tales, in my favour. I've got enough for 50 boards or so.

Oh well gives me an opportunity to try out an ARM solution.

Cheers

[charliex]

I think someone is following me around buying the parts, I bought half of mousers stock, went back to get the other half and its gone just in a few hours ! 

whomever it is, email me and sell me some chips !

I just got back my first batch of PCB's from Batchpcb (sparkfun) they're pretty decent, especially for the cost and the turnaround time was about what they say. I was going to use advance circuits for the test run and kitting (they're bad at communication), but on first visual these look pretty good.

[charliex]

Well i laid my hands on what i could, and then ordered a LPC2378 ARM dev board from Keil.

I did find some more chips at farnell in Oz since we have offices there and they don't ship here apparently, but lordy you guys are getting screwed on prices over there, almost double!

[TheDirty]

If you are replacing AVR chips, you should be trying the LPC13xx or LP17xx Cortex-M3.  They're faster, cheaper, and easier to use.

[charliex]

Thanks Mark, that does indeed look like a better match LPC1768 looks pretty close to my needs and cheaper!