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Forum Index : Microcontroller and PC projects : cpu speed of picomite...
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| hhtg1968 Senior Member  Joined: 25/05/2023 Location: GermanyPosts: 114 |
Hello. i have about 8 picomites. some run with 378 mhz, some with 252 mhz, one only with 126 mhz. are there rp2040 from different sources? is it random? |
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| hhtg1968 Senior Member Joined: 25/05/2023 Location: GermanyPosts: 114 |
i have running a picomiteVGA with 378 mhz for about one week without problems (if i test it with my finger: it is not hot!). my cmm2 is running at 480 mhz and you could cook on the cpu...! the picMz on my colour maximite 1 (i have the all...) stays cool... |
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stanleyella Guru  Joined: 25/06/2022 Location: United KingdomPosts: 1650 |
378 mhz works on my 4 and one is waveshare with lcd. it really speeds things up and the chip never goes above 27C |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5750 |
I think all (or at least most) of the official RPi Pico boards will run happily at 378MHz. The Waveshare RP2040-Zero that I'm currently playing with is also happy at this speed. The problem comes with some of the Chinese copies, which seem to use slower flash chips, particularly if they are 16Mb. They still run perfectly at the official RPi spec of 133MHz so there's nothing actually wrong with them in that respect, they just can't handle overclocking. Note that RPi don't test at 378MHz so there's no guarantee that any of their boards can do it either. You may find some that won't. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| stanleyella Guru Joined: 25/06/2022 Location: United KingdomPosts: 1650 |
any links to fake Chinese copies... to avoid? Edited 2023-06-16 07:57 by stanleyella |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5750 |
They aren't "fakes" at all. The Pico design is open, anyone can use it providing they aren't actually cloning the RP2040 itself - and it's probably uneconomical to do that as bulk prices for the official chip are very low. There is nothing wrong about selling your own boards using the RP2040, Raspberry Pi encourage it! YD-RP2040 runs out of steam at 200MHz, otherwise it seems to be a not bad 16Mb board, although slightly pin incompatible. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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Plasmamac Guru Joined: 31/01/2019 Location: GermanyPosts: 503 |
Have several picos from different sellers, only 2 can run 378 Mhz. And if i remember right my cmm2 will not become hot , need check this weekend Plasma |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9070 |
As Mick says, it would appear to NOT be the 2040 chip that can't handle the overclocking, but the flash memory chip that cannot handle the faster clock on some of the cheaper modules. So, I would not be worried about "Clone" 2040 chips, as I expect they are all genuine product, for the exact same reason that Mick states.(they are so cheap in bulk anyway, that making clones really is not saving anything, so it is unlikely to be done) I myself am dubious about overclocking. I have NEVER liked the idea, and so never try to do it in anything, including PC CPU's etc when you could. Perhaps I am just being paranoid, but I find running hardware faster then it was designed to run, is somewhat similar to running an engine at red-line. YES, you CAN do it, but how long will it last before it blows itself to bits is anyone's guess. My 2c only.  Smoke makes things work. When the smoke gets out, it stops! |
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| barewires Newbie  Joined: 13/04/2015 Location: United KingdomPosts: 25 |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5750 |
What shortens a chip's life is temperature. An increase in temperature can be for all sorts of reasons: High ambient, excessive voltage, insufficient heatsink. Overclocking isn't the problem in itself, it just leads to increased dissipation and hence an increase in temperature. The RP2040 is very effective at dissipating heat. It's a tiny die and the package is relatively large in able to get all the necessary pins. Consequently it dissipates heat very well just by natural convection and conduction into the PCB. The hottest I think I've run one was a 378MHz RP2040-Zero with a die temperature of 47C (according to the on-die sensor diode using PIN(TEMP)) at an ambient of 25C. That's well within the possible 135C capabilities of the silicon and it's run all day like that for several days. The package didn't feel warm as just about all of the heat is conducted into the PCB and dissipated from there. On the RP2040 you can't do things like increasing the core voltage to get "real" overclocking so you aren't stressing on chip components to cause hot-spots around voltage regulators etc. Pushing up the clock speed is relatively mild and is very unlikely to ever cause problems. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8600 |
if(Option.CPU_Speed>200000)vreg_set_voltage(VREG_VOLTAGE_1_25); // Std default @ boot is 1_10 |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5750 |
Oh! I didn't know about that. I've obviously not read the 600 or so pages of the Datasheet closely enough. :D Whatever - the die is tiny so will heat fairly equally and I'm more than happy with the temperature at 378MHz anyway. :) Edited 2023-06-16 17:38 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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