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Forum Index : Microcontroller and PC projects : Is there a pin-compatible, over-clockable, USB-C Pico clone ?
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thwill Guru  Joined: 16/09/2019 Location: United KingdomPosts: 4043 |
Hi folks, Subject says it all. I am running out of original Raspberry Pico's and if possible I'd like my next batch to have USB-C. Best wishes, Tom Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
The RP2040-Zero from Waveshare is ok but is tiny and has less IO. Really cute with a little SPI LCD display though. :) I think Waveshare also do a standard size one with USB-C. That might be what Peter has been using. The YD-2040 only overclocks to 200MHz and is slightly pin incompatible, but it has extra flash and IO. 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: 4247 |
Ah Tom, You are degrading the Bintendo Tomboy. That hurts. ;) Many clones have linear regulators. You may want to check if this matches your design (will it run for 1 lithum cell in full load including backlight and overclocked). 1 cell full is 4.2V, but empty near 3.3V (below 3.7V certainly). Volhout Edited 2023-06-08 01:30 by Volhout PicomiteVGA PETSCII ROBOTS |
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| thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 4043 |
Every time I pull the USB from a standard Pico I think I'm going to rip the socket off the board, I don't get that with USB-C. Best wishes, Tom Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 4247 |
You only need USB when developing. you can use a DC jack (anything robust enough) plug and connect that to Vsys and GND through a diode. That is what Mick does and Peter does.. Edited 2023-06-08 01:34 by Volhout PicomiteVGA PETSCII ROBOTS |
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Sasquatch Guru Joined: 08/05/2020 Location: United StatesPosts: 362 |
These seem to fit the bill: https://www.aliexpress.us/item/3256804731684211.html I bought 10 of them a few weeks ago. I haven't tried them yet. The only issue with overclocking should be the flash memory speed. The part number on the flash memory on the ones I received is Winbond 25Q128JVSQ. Assuming they aren't fake this should be the highest speed version? I'll solder some headers on one and try overclocking it... stay tuned! -Carl |
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| thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 4043 |
Looks good, I will wait with baited breath. Or I could just reverse the LiPO charger module, the USB-C on that is currently facing into the board and unusable, instead it is powered by VBUS on the Pico. This is deliberate to minimise port confusion. The Bintendo has only two ports: 1. The Pico's USB which also serves as the charging port for the LiPO. 2. An optional 2x7 R/A boxed male header which carries the spare I/O (including the analog pins) + duplicates of the two audio pins + multiple 3V3 and GND. There is also a 10-pin header in the controller section which breaks out the GP for the 8 buttons (not including RESET) + 3V3 + GND so that the PCB can be repurposed. Best wishes, Tom Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
Have a look at the RP2040-Plus board by Wavesahar, Tom. It looks like it may be ideal. I bet it will overclock too as Waveshare seem to be pretty good. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Sasquatch Guru Joined: 08/05/2020 Location: United StatesPosts: 362 |
Ok, Based on a sample size of one, It seems to be running fine at 378000MHz. I am running with PicoMiteVGA 5.07.07 I'll let it run Mandelbrots overnight to make sure it's stable. So far I'm, not noticing anything unusual. Any other specific tests I should run to verify the device? It does seem to have a "Buck" regulator for the 3.3V so it's doubtful that it will run on less than 5V input power. The regulator is TD6810. While the datasheet indicates operation down to 2.5V on the input, it also mentions "dropout voltage" and I see no indication that it is capable of "Boost" operation. Edited 2023-06-08 03:31 by Sasquatch -Carl |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
If Tom is running it at 3V7 then a linear regulator is unlikely to be of any use. He'll need the onboard SMPS (or an outboard one) to get a decent battery life. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 4043 |
Yes, I am running the Bintendo from a LiPO at 3V7, so does that exclude the device linked by @Sasquatch ? In ignoramus language can someone explain the linear regulator vs. SMPS argument ? The Waveshare RP2040-Plus looks a bit rich for my blood, almost 10 UKP per device  .Best wishes, Tom Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6100 |
A linear voltage regulator will always have a lower volts out. Usually 0.3 V less for very low drop out ones and up to 2V+ for the usual ones. The switch-mode used in the pico can step the volts UP as well as down so input voltage is not such a problem. Not all switch-modes can put out higher voltage than the input. The disadvantage of switch-mode regulators is they are 'noisy'. Jim Edited 2023-06-08 17:36 by TassyJim VK7JH MMedit MMBasic Help |
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| thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 4043 |
Thanks Jim, how does this inform Mick's comment about battery life: Is this the same argument that explains why the BBC initially insisted that the BBC Micro had a linear power supply ... which didn't last long, most of them have smaller switching power supplies. Best wishes, Tom Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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Turbo46 Guru Joined: 24/12/2017 Location: AustraliaPosts: 1611 |
Switch mode regulators are usually quite efficient 80-90 percent or so while a linear regulator is MUCH less efficient. The power consumed in a linear regulator is determined by the voltage difference between the input and output voltage and the current drawn by the device it is supplying Bill Keep safe. Live long and prosper. |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 9129 |
Take an example 3.7V in 3.2V out using a decent quality low dropout linear regulator What happens to the 0.4 volts? Answer HEAT. So, suppose you are drawing 100mA with your circuit then the efficiency of a linear regulator is 3.3/3.7*100 = 89% with 0.1*0.4 = 0.04 watts of heat BUT Now feed the regulator with 5V and the efficiency is now 3.3/5*100 = 66% with 0.1 * 1.7 = .17 watts of heat SO With a lipo battery a linear regulator will likely be as good or better in efficiency as a switch mode but the advantage disappears quickly as the input voltage increases BUT (AGAIN) The output voltage of a linear regulator will always be not more than the input voltage less the dropout voltage so as the lipo drops to 3.3V then the output assuming a dropout voltage of 0.2 volts will only be 3.1V |
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| Sasquatch Guru Joined: 08/05/2020 Location: United StatesPosts: 362 |
Bottom Line: The "original" PiPico is rated for input voltage (VSYS) from 1.8-5.5V. Most of the "clone" modules have either a linear regulator or a "Buck" mode regulator. As @Matherp points out, these types of regulators will always have a lower output voltage than the input. Just how much lower will depend on the specific regulator device and the current load. The minimum voltage difference between input and output is often referred to as "dropout voltage" In this regard, the "original" PiPico is superior for operation over a much wider range of input voltages (i.e. Battery operation) Now, having said all that, lets look at the specific device I posted the link for earlier: https://www.aliexpress.us/item/3256804731684211.html The RP2040 chip itself specifies operation over the range of 1.62-3.63V with at least 3.135V required for the USB port to function correctly. The other consideration is that no I/O pin should have a voltage applied of more than IOVDD + 0.5V This should not be an issue as long as the regulator on the module is the only regulator in the system. The Winbond 25Q128JVSQ flash memory indicates a working voltage from 2.7-3.6V I suspect overclocking of the flash memory may not be possible at the lower end of the voltage range. The spec sheet for the specific regulator IC used on that module tells us that it is specifically designed to operate with the input below the set voltage (3.3V) with a very low "ON" resistance of a few hundred milli ohm. (see quote in post above) Again, how low will depend on the current draw. Note that this may not be true of other regulator devices! The LiPo battery has a working voltage of 4.2V (charging) to 3.2V (nearly fully discharged) This would cause the voltage at the RP2040 chip to drop below 3.3V when the battery is nearly empty. Theoretically this should not pose any real issues, although operation of the USB port would not be recommended with a nearly empty battery. Of course this is all theory and I haven't run any tests, but the module should work OK with a single LiPo battery provided that the voltage on the RP2040 does not drop too low for overclocking! Give me a couple of days and I will do some testing to see how low the input voltage of the module can go with and without overclocking! On another note, my test module ran overnight at 378MHz with no issues. I have an additional module running "DOOM" in demo mode overnight, also no issues! The build notes for RP2040 DOOM indicate a CPU clock speed of 270MHz with the flash memory slightly overclocked at 135Mhz. This module is quickly becoming my favorite PiPico clone! Edited 2023-06-09 01:31 by Sasquatch -Carl |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
That looks like a good one, Carl. I approve of the colour too. :) One very minor niggle - I can't wire GP25 off the board as the test point is missing. Only the original has that AFAIK. I don't know of anyone else that would want to do that though. :) I might get a few of these. Cheap. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Sasquatch Guru Joined: 08/05/2020 Location: United StatesPosts: 362 |
Ok, here is some data on low voltage operation of the PiPico clone module: The voltage drop across the regulator when operated below the set-point (3.3V) is about 0.1V This is with power applied to the VSYS pin, the regulator on the Pico clone is also running the SD card, RTC and PS/2 keyboard. There is a diode between VUSB and VSYS which would drop another 0.5-1V if power were applied to the VUSB pin. Everything seems to work fine at 378MHz down to about 3.0V on VSYS other than the fact that the VGA colors start to look a bit off. Below 2.8V on VSYS,the SD card won't initialize. At 2.6V on VSYS the PS/2 keyboard is still working, the VGA colors are way off and the LED's on the keyboard are barely visible. I am running Mandelbrot in a continuous loop at 2.6V for some time now with no issues (the SD card is now removed) At 2.5V on VSYS, the Pico clone locks up and requires a hard reset. This may be due to the flash ram operating at high speed below it's specified voltage. Keep in mind this is for a sample size of one. I don't think I'd recommend operating the module below 3.0V but it looks promising for operation with a single LiPo cell down to 3.2V applied to the VSYS pin. Update: At 2.6V the PS/2 keyboard eventually locked up when I hit the "Caps Lock" key to observe the LED. The Mandelbrot is still running! Edited 2023-06-09 03:30 by Sasquatch -Carl |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3150 |
Good information, though. Thanks for doing the research and sharing it. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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ice2642 Regular Member  Joined: 27/05/2023 Location: BrazilPosts: 82 |
Get a look in this board, USB-C and 16mb Chinese pico And very cheap I plan buy some to test. Best regards, MMBasic 5.0707 on PicoMite VGA |
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