tonygo2
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Numbers on Pico Chip

Sat May 08, 2021 10:31 am

I've got several RP2040 boards and noticed that the numbers printed on the top or the RP2040 chip are very different.

RP 2040 Chip Numbers
# Board ID1 ID2 ID3 ID4
1 PICO UK RP2-80 20/34 P64M15.00 TTT
2 PICO UK RP2-80 20/34 P64M15.00 TTT
3 PICO UK RP2-B1 20/38 P64M16.00
4 PICO UK RP2-B1 20/43 P65A42.00
5 PICO Malaysia RP2-B0 20/34 P64M15.00 TTT
6 PICO USA RP2-B1 20/38 P64M16.00
7 Pimoroni Tiny 2040 UK RP2-B1 20/43 P65A42.00
8 Adafruit ItsyBitsy 2040 USA RP2-B1 20/43 P65A42.00

It may not be essential to how they run but I'd be interested to know what they mean.

drgeoff
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Re: Numbers on Pico Chip

Sat May 08, 2021 10:50 am

The B0 is the original production version. There was a subsequent minor respin (IIRC changing the ROM code) and that is the B1. I don't know what the other numbers mean. Possibly related to manufacturing dates or plants.
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rpdom
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Re: Numbers on Pico Chip

Sat May 08, 2021 11:07 am

The 20/34 etc will be the manufacture date. Week 34 of 2020.
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aallan
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Re: Numbers on Pico Chip

Sun May 09, 2021 12:57 pm

tonygo2 wrote:
Sat May 08, 2021 10:31 am
RP 2040 Chip Numbers
# Board ID1 ID2 ID3 ID4
1 PICO UK RP2-80 20/34 P64M15.00 TTT
2 PICO UK RP2-80 20/34 P64M15.00 TTT

You'll have misread these, that'll be RP2-B0, not RP2-80.
3 PICO UK RP2-B1 20/38 P64M16.00
4 PICO UK RP2-B1 20/43 P65A42.00
5 PICO Malaysia RP2-B0 20/34 P64M15.00 TTT
6 PICO USA RP2-B1 20/38 P64M16.00
7 Pimoroni Tiny 2040 UK RP2-B1 20/43 P65A42.00
8 Adafruit ItsyBitsy 2040 USA RP2-B1 20/43 P65A42.00

B0 and B1 signifies the B0 and B1 versions of the chip, the B1 is a minor respin with some bootrom changes, see the RP2040 Datasheet for details.

TTT signifies "typical" silicon, i.e. it's not corner silicon, https://en.wikipedia.org/wiki/Process_corners.
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tonygo2
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Re: Numbers on Pico Chip

Sun May 09, 2021 1:14 pm

Thank you.
Much more information than you normally get on a chip face.
I'm surprised how long it was between manufacture and launch.

(Eyes not so good after 76 years - but I'm trying to keep up.)

hippy
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Re: Numbers on Pico Chip

Sun May 09, 2021 3:21 pm

aallan wrote:
Sun May 09, 2021 12:57 pm
TTT signifies "typical" silicon, i.e. it's not corner silicon, https://en.wikipedia.org/wiki/Process_corners.
So, if a chip is not marked "TTT" does that means it's not "typical", is "corner silicon" ?

The way I am reading that Wikipedia page is that "corner silicon" is potentially more dodgy or unreliable than that which is "typical". Is it as bad as it sounds to me ?

Or is "corner silicon" marked so unmarked sits between "TTT" - the good stuff - and "corner silicon" - the potentially less good stuff ?

cleverca22
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Re: Numbers on Pico Chip

Sun May 09, 2021 3:56 pm

hippy wrote:
Sun May 09, 2021 3:21 pm
The way I am reading that Wikipedia page is that "corner silicon" is potentially more dodgy or unreliable than that which is "typical". Is it as bad as it sounds to me ?
i would assume that the 125mhz rating in the datasheet, covers corner silicon as well
the "typical" silicon may accept a larger overclock, compared to corner silicon, but your operating outside of the official limits

hippy
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Re: Numbers on Pico Chip

Sun May 09, 2021 6:06 pm

That makes sense. All chips will have passed testing for what the standard ratings are, but going beyond that isn't guaranteed, some chips can be pushed further.

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aallan
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Re: Numbers on Pico Chip

Mon May 10, 2021 8:28 am

hippy wrote:
Sun May 09, 2021 3:21 pm
aallan wrote:
Sun May 09, 2021 12:57 pm
TTT signifies "typical" silicon, i.e. it's not corner silicon, https://en.wikipedia.org/wiki/Process_corners.
So, if a chip is not marked "TTT" does that means it's not "typical", is "corner silicon" ?

The way I am reading that Wikipedia page is that "corner silicon" is potentially more dodgy or unreliable than that which is "typical". Is it as bad as it sounds to me ?

Not exactly, the Wikipedia page is somewhat sparse. There will be a distribution of speeds in a batch of chips, because process variables like oxide thickness, effective channel length, and doping concentration all have statistical distributions. There will then be a mean and a standard deviation associated with this speed distribution. The typical process model is supposed to model the mean speed that you would expect to see, and the process corner models are supposed to capture some variation from the mean. If other words corner silicon can be "better" than typical silicon as well as "worse".

Process variation is why you're seeing folks able to overclock some RP2040 chips more than others. However all the parts should perform within the tolerances laid out by the datasheet.
Or is "corner silicon" marked so unmarked sits between "TTT" - the good stuff - and "corner silicon" - the potentially less good stuff ?

You'll only see the part marking for typical or corner silicon on B0 chips. The B1 chips aren't marked.

There is no corner silicon in circulation outside of the company and available to the public AFAIK.
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jamesh
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Re: Numbers on Pico Chip

Mon May 10, 2021 9:16 am

tonygo2 wrote:
Sun May 09, 2021 1:14 pm
I'm surprised how long it was between manufacture and launch.
We needed to get Pico's made and fill up the supply chain and also get devices to third parties who were making their own boards. That's quite a lot of time.
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