When will we return to normal microcontroller stock availability?

[brucehoult]

So you can get a 555 for 5c. Cool. What can you get an ATTiny25 or the equivalent 8 pin PIC for?

Its a long time since I looked, but the reason people were amazed by the 3 cent Padauk MCUs is they a fraction of the price of anything else. I think PICs probably start around 10 cents for those really simple ones in tiny packages, in high volume. As you add more pins the A&T costs rapidly rise.

One factor in the 3c Padauks is that they are OTP. They have ones with flash program memory too, but they cost quite a bit more.

[coppice]

So you can get a 555 for 5c. Cool. What can you get an ATTiny25 or the equivalent 8 pin PIC for?

Its a long time since I looked, but the reason people were amazed by the 3 cent Padauk MCUs is they a fraction of the price of anything else. I think PICs probably start around 10 cents for those really simple ones in tiny packages, in high volume. As you add more pins the A&T costs rapidly rise.

One factor in the 3c Padauks is that they are OTP. They have ones with flash program memory too, but they cost quite a bit more.

That OTP issue intrigues me. It really adds to the die area to make a small flash MCU self-programmable, because of the die area of the charge pump required. However, if you accept that the flash needs to be programmed by an external programmer, and you put the voltage generator in there, the use of reprogrammable flash doesn't really have an overhead.

[SiliconWizard]

Yes it does have an overhead however you see it.
But the main point is elsewhere: as I think we already discussed in earlier threads, CMOS processes that offer embedded Flash are fewer and more expensive, so the cost of dies is significantly higher, whether you actually embed Flash or not, or even if it's just a small area of it. While OTP is usually available on a wider range of CMOS processes at a lower price point.

[coppice]

Yes it does have an overhead however you see it.
But the main point is elsewhere: as I think we already discussed in earlier threads, CMOS processes that offer embedded Flash are fewer and more expensive, so the cost of dies is significantly higher, whether you actually embed Flash or not, or even if it's just a small area of it. While OTP is usually available on a wider range of CMOS processes at a lower price point.

Most modern processes are only set up for flash. Perhaps these tiny MCUs are pad limited, despite their low pin count, so an old large geometry process with EPROM support is still the cost effective solution. Does anyone know who fabs for Padauk?

[PlainName]

Don't those tiny MCUs have a reprogrammable development version? Doesn't matter if it costs £20 or something - you use that single device to develop and then roll out a billion OTP parts knowing you've got the code right.

[coppice]

Don't those tiny MCUs have a reprogrammable development version? Doesn't matter if it costs £20 or something - you use that single device to develop and then roll out a billion OTP parts knowing you've got the code right.

As you said, it not a big drawback. I just found it odd that what appears to be recently developed silicon didn't naturally gravitate to a reprogrammable approach.

[SiliconWizard]

Yes it does have an overhead however you see it.
But the main point is elsewhere: as I think we already discussed in earlier threads, CMOS processes that offer embedded Flash are fewer and more expensive, so the cost of dies is significantly higher, whether you actually embed Flash or not, or even if it's just a small area of it. While OTP is usually available on a wider range of CMOS processes at a lower price point.

Most modern processes are only set up for flash.

Nope. But just have a look at the offering at TSMC, GlobalFoundries and whatever else you like.

[coppice]

Yes it does have an overhead however you see it.
But the main point is elsewhere: as I think we already discussed in earlier threads, CMOS processes that offer embedded Flash are fewer and more expensive, so the cost of dies is significantly higher, whether you actually embed Flash or not, or even if it's just a small area of it. While OTP is usually available on a wider range of CMOS processes at a lower price point.

Most modern processes are only set up for flash.

Nope. But just have a look at the offering at TSMC, GlobalFoundries and whatever else you like.

Specify some actual processes that are not flash, or flash without a charge pump acting like some kind of fake EPROM, that isn't ancient.

[brucehoult]

Yes it does have an overhead however you see it.
But the main point is elsewhere: as I think we already discussed in earlier threads, CMOS processes that offer embedded Flash are fewer and more expensive, so the cost of dies is significantly higher, whether you actually embed Flash or not, or even if it's just a small area of it. While OTP is usually available on a wider range of CMOS processes at a lower price point.

Most modern processes are only set up for flash.

Nope. But just have a look at the offering at TSMC, GlobalFoundries and whatever else you like.

Specify some actual processes that are not flash, or flash without a charge pump acting like some kind of fake EPROM, that isn't ancient.

I don't know the answer to that.

I do know, from my own experience that the SiFive FE310 (TSMC 180nm) and FU540 (TSMC 28nm) both provide a few kb (8 and 16 respectively) of OTP, and no flash. They use external SPI flash for firmware.

Incidentally, the code in OTP (as delivered from the factory on the HiFive1 and HiFive Unleashed boards) starts with a RISC-V FENCE instruction 0x0000000F, which can be easily burned later to an up to ±1 MB relative jump 0xnnnnn06F.

I'd be interested to know the similar tricks that work on other ISAs.

Having all 0s be a NOP would be the simplest thing, but the RISC-V designers deliberately made both all 0s and all 1s be illegal instructions to try to detect execution off into the weeds ASAP.

[passedpawn]

Even 32.768kHz crystals that go with 32-bit MCU's, are in short supply. Some of 12.5pF but 6-9pF is months away. I know quartz crystals takes time to grow I guess it's demand related that shortage?

I am also watching LM555 stock for amusement, not that anyone designs these in - but it's been around for 50 years and imagine the dwindling stock running out.

I actually put one in a design at work last year. We had the 1PPS coming out of a ublox GPS module, which I think has about 100ms pulse width at 3.3v. In the former design it went to the input of a uC, no problem. The requirement changed in that it needed to mimic a military GPS unit for which the 1PPS is specified (if I'm remembering correctly) 5V, 20 usec into 50 ohms. Using a 555 as a one shot, I was able to get a pulse narrower, and have enough umph to drive 50 ohms (picking the right 555). Pulled a DIP 555 out of my at home stash, tried it out on a breadboard, and bingo, it worked. Used an SO8 of the same part for the design. 555 is still useful, but there are simpler ways to blink an LED.

The pps signal on ublox chips is programmable.  Not sure about pulse width, but certainly the pps. 

[Deni]

37 years lead time...

[SiliconWizard]

At least they're not trying to lead you on.
(The situation is not funny though.)

[Monkeh]

"Hey guys, when can we get these parts, our customers are asking"
"2059, now fuck off!"

[Doctorandus_P]

And what is the Lead free time? 

[tepalia02]

Wanna know the answer too.....

[hans]

Atleast it's not on a Friday the 13th. Then atleast, you don't have that bad luck working against you.

[anda3243]

This crazy lockdown in China will not help eather. I think a second big supply chain disruption is coming. The big port in Shanghai has been closed for almost a month. Most businesses in and around Shanghai is closed, including the few IC manufacturers. Have been closed for a month. Beijing will shut down soon I think.
So far the Shenzhen area has had very few shutdowns, but it might come as well. Alot of ICs are made in Shenzen area.

Overall China might not be a huge exporter of chips. But these stupid covid shutdowns will cause more chip related shortages. More than the Ukraine war for sure.

[SiliconWizard]

Noticed that when something I ordered a while ago now was supposed to arrive more than a month ago, and is still blocked there.

[nigelwright7557]

RS Components is limiting semiconductor supplies.
I can get one off PIC32mx230 for £4-ish
Their 30 off much cheaper option is out of stock.
There are plenty of one off's to cover the 30 offs too.

The prices are going up too. A PIC that was around £2 is now nearer £4.

[SiliconWizard]

FPGA prices have gone through the roof as well.