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Forum Index : Microcontroller and PC projects : finally permanent full speed without hickups - pico w
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Plasmamac Guru  Joined: 31/01/2019 Location: GermanyPosts: 554 |
hi, i bought a new pico-w and its the thirst pico which runs on 378000 cpu speed.  Plasma |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 4250 |
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 |
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| Plasmamac Guru Joined: 31/01/2019 Location: GermanyPosts: 554 |
All other picos cant run so high. All from the same seller and all genuine 😀 Plasma |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
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 |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 4250 |
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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