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Forum Index : Microcontroller and PC projects : finally permanent full speed without hickups - pico w

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Plasmamac

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Joined: 31/01/2019
Location: Germany
Posts: 500
Posted: 06:18pm 19 May 2023
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hi,

i bought a new pico-w and its the thirst pico which runs on 378000 cpu speed.

Plasma
 
Volhout
Guru

Joined: 05/03/2018
Location: Netherlands
Posts: 3422
Posted: 12:20pm 20 May 2023
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I only have genuine RP boards. Mijne all run 378 MHz.

When in doubt , buy original.

Volhout

P.s. But I have plenty Arduino clones..
PicomiteVGA PETSCII ROBOTS
 
Plasmamac

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Joined: 31/01/2019
Location: Germany
Posts: 500
Posted: 01:46pm 20 May 2023
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All other picos cant run so high. All from the same seller and all genuine 😀
Plasma
 
Mixtel90

Guru

Joined: 05/10/2019
Location: United Kingdom
Posts: 5645
Posted: 02:55pm 20 May 2023
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I don't think it's a problem with the essential bits of the design. AFAIK all the clones meet the *standard* for the Raspberry Pi Pico. We are the ones that push them too hard. :)  The clones are fine *if you want clones of the Pico* (often with enhancements). I think they usually use slower rated flash chips, which saves money and they are still within the Pico spec. You may find some that run fast, but they may not be reliable (mind you, the Pico isn't officially rated for overclocking either).

You pays your money and you takes your choice. Just don't expect top performance at cheap prices. :)
Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs
 
Volhout
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Joined: 05/03/2018
Location: Netherlands
Posts: 3422
Posted: 07:29pm 20 May 2023
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Peter will correct me if I am wrong, but I remember a discussion about overclocking the pico.
The ARM processor runs at the speed we use in OPTION CPUSPEED
The SPI memory runs at different speed when we overclock.
The SPI device (I checked datasheet) is designed for 133MHz clock speed.

So a picomite at 126 or 133 MHz can read the SPI device at maximum speed.
But a 378MHz ARM can not expect the SPI device to run at 378MHz (the RP2040 IO pins won't even do that). That is why Peter has implemented different SPI speeds.

The SPI speed changes depend on the CPUSPEED setting.
I think up to 200 or 250MHz the speed is the same as the CPU, and above it is divided down to a lower speed.

So it may be possible your picomite does not run at 180MHz, but it will at 252MHz.
At 180MHz the SPI chip is very much overclocked, but at 252MHz it could be running at 126Mz (252:2) and operate within spec.

Again, the above numbers may not be correct, but in essence I think this is what is happening. And it may pay of to check various settings.

And about "your milage may vary...."
This is very much depending on chips, tolerances, board layout, power supply(*).

Volhout

(*) when chips are driven to the extremes, they consume more power. That is why some have water cooled PC's....
PicomiteVGA PETSCII ROBOTS
 
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