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Forum Index : Microcontroller and PC projects : Bummer .....
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hitsware2 Guru  Joined: 03/08/2019 Location: United StatesPosts: 719 |
....With this one Blinks the LED, but doesn't hold the program when unpluged  my site |
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panky Guru Joined: 02/10/2012 Location: AustraliaPosts: 1114 |
Doesn't hold MMBasic or an entered program? ... almost all of the Maximites, the MicromMites, the MM Extremes, the ArmMites, the PicoMite and loving it! |
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| toml_12953 Guru Joined: 13/02/2015 Location: United StatesPosts: 442 |
Since it has no FLASH memory onboard, I don't see how it could. It has FLASH on an external QSPI but the mechanism for writing to it is different than with the CMM2 or other systems that have onboard FLASH. |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7937 |
Are OPTIONs being saved? Are the Flash slots working? Does AUTORUN n work? Which MBasic release? Edited 2021-11-02 17:22 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7937 |
The RP2040 has no Flash, toml, just the 264k RAM and a bit of cache memory. The Flash is always external to it. The difference in this case is that they have provided a bigger chip. It is accessed using QSPI just as it is on the Pico. Edited 2021-11-02 17:33 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| hitsware2 Guru Joined: 03/08/2019 Location: United StatesPosts: 719 |
After unplug - plug back in ...... It is no longer a serial port Appears like original ( as far as I see ) my site |
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| hitsware2 Guru Joined: 03/08/2019 Location: United StatesPosts: 719 |
This one I have'nt got further than blinking a led ... my site |
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| hitsware2 Guru Joined: 03/08/2019 Location: United StatesPosts: 719 |
Pico works fine  my site |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 10310 |
The reason could be that they are doing something strange with GP21 Out on interest try the attached which removes GP21 from the initialisation PicoMite.zip |
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| robert.rozee Guru Joined: 31/12/2012 Location: New ZealandPosts: 2442 |
looks like GP21 is tied to the BOOTSEL switch: adafruit_products_QTRP_sch.pdf cheers, rob :-) Edited 2021-11-02 23:31 by robert.rozee |
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| hitsware2 Guru Joined: 03/08/2019 Location: United StatesPosts: 719 |
Same .... It is possible I some way bricked that one . I ' ve ordered 2 more plus two of these so we ' ll see what happens . my site |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7937 |
This is probably always going to be a problem. We don't know, and have no control over, what pins are allocated to on-board stuff. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| scruss Regular Member  Joined: 20/09/2021 Location: CanadaPosts: 91 |
I don't have any of the QtPy RP2040s in stock to try it with, but the PicoMite ran on the quite different SparkFun Pro Micro - RP2040 which moves some things around: f'rinstance, the LED pin (GP25) now runs a WS2812, so at least you don't get the infernal blinking when the board's idle. |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9610 |
...you can disable the blinking LED on the PicoMite if it is annoying you.  Page 107 of manual: SETPIN GP25,DOUT | HEARTBEAT I guess that does not fix the idle state you refer to, but so long as a code is running, you can turn that blinking LED off. You could always cover the LED with a bit of blu-tak or something - that would make it effectively invisible under all conditions. Smoke makes things work. When the smoke gets out, it stops! |
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| hitsware2 Guru Joined: 03/08/2019 Location: United StatesPosts: 719 |
Thank You !  With an audio amp near by , that LED radiates enough RF into the circuit to be audible ( sounds more like breathing than heart beating ) my site |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2640 |
The "breathing" sound could be hash coming from the 5V to 3.3V converter, the LED blinking is changing the load on it. Assuming the amp has it's own power source, put a 4.7 to 22 ohm resistor (trial and error for the best value) in the earth link between the amp and the PicoMite. This may reduce the noise somewhat. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7937 |
That dc/dc converter is *very* noisy. The LED probably doesn't radiate any RF but the converter almost certainly does! You can disable it by grounding the 3V3_EN pin (37) then use an external 3V3 linear LDO regulator from 5V (VBUS or VSYS) into the 3V3(OUT) pin (36). While shut down the converter goes into a very low current mode and turns off its output mosfet , so it's effectively isolated. Don't be too worried about doing this, it's in the data sheet for the chip. :) 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: 5089 |
The Raspberry Pi Pico has a switching regulator that is noisy. Most of the boards discussed here have linear regulators. Check the schematics ! Not sure if the noisy LED discussion relates to a switching regulator. It could be that the board layout is not very good and the chip itself emits RF noise. Volhout PicomiteVGA PETSCII ROBOTS |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7937 |
Raspberry Pi say that the Pico board layout was designed at the same time as the RP2040 and is optimised for it. That's why there are so many ground connections, it's not just for convenience, it's to reduce EMF from the very fast signal edges that can occur. The dc/dc converter is what it is - if you fit one you get noise. All switching converters are noisy, it's just that some are worse than others. :( Luckily you don't *have* to use it. AFAIK modern LEDs aren't particularly noisy. At one time you could get a lot of impulse noise from them (and use them as a front end in random number generators!). You'll get plenty of noise from many LED light fittings, but not from single LEDs. Edited 2021-11-03 19:17 by Mixtel90 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: 5089 |
Multicolor led's like the WS2812 may be noisy.... The serial datastream certainly may be. PicomiteVGA PETSCII ROBOTS |
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