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Forum Index : Microcontroller and PC projects : Colour Maximite 1.5? or something

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phil99

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Joined: 11/02/2018
Location: Australia
Posts: 2135
Posted: 10:37pm 13 Mar 2024
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VBUS is on Pin 40 of the Purple module.
A regular USB-A to C cable can be used with an adapter made from a dual USB-A socket with the pins of the two sockets wired together.
Edited 2024-03-14 08:38 by phil99
 
bigmik

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Joined: 20/06/2011
Location: Australia
Posts: 2914
Posted: 11:04pm 13 Mar 2024
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Hi All,

Some interesting comments there.

Honestly, it is ‘horses for courses’

If you need to get the extra functionality of extra GPIO then you probably have to go for the individual components mounted on the PCB approach, at a sacrifice of a more difficult to repair status.

Yes, you could use a Purple or Black clone Pico but, after looking at the pictures of them, if you want USB support you will have to use a sacrificial cable to gain access to the D+, D- pins of the Pico. Quality also seems to be an issue with some of these clones not being able to reach the speeds of a genuine Pico.

If you want the possibility of replacing a Pico because of future damage that it may receive and you are happy with the reduced GPIO (in many cases the reduced IO will not be an issue) then you can opt for a design that uses a socketed Pico.

With respect to the latter condition…. Watch this space.

Kind Regards,

Mick (the big one)



.
Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<
 
matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 9115
Posted: 08:35am 14 Mar 2024
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  Quote  If you can make your own PCB use Peter's circuit with a "RP2040 16M Purple" module. It has the extra pins and 16Mb flash.
Same size as a standard Pico but different pin layout. Less ⏚ pins to make room for the extra GPIO pins. A little cheaper too, eg.


I hadn't seen that one - very useful unit - has anyone tried one?

You could certainly do my board using this module to have a "replaceable" RP2040 if that is a big deal. The only downside is having to use a USB-C to USB-A adapter for most keyboards but at least USB-C is reasonably robust unlike micro-USB AND USB-C keyboards are now widely available.

All my development of the USB code was using a standard Pico and I can absolutely guarantee that micro-USB is not fit for purpose if used for a keyboard/hub connection. I spent too much time bending the micro-USB shell to try and get a good connection when things that were working stopped for no reason.

Note though that none of the Pico modules have the 15K pulldown resistors on the USB D+ and D- lines that indicate the post is a USB-host. This doesn't seem to matter but is incorrect and these are included on my designs.
Edited 2024-03-14 18:45 by matherp
 
phil99

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Joined: 11/02/2018
Location: Australia
Posts: 2135
Posted: 11:46am 14 Mar 2024
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  Quote  has anyone tried one?
Have been using one for a year, runs reliably at 378MHz. The 3.3V reg. is linear so less noise but also lower max. current.
 
bigmik

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Joined: 20/06/2011
Location: Australia
Posts: 2914
Posted: 03:21am 15 Mar 2024
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Hi Lizby, Peter, All,

I have Lizby's faulty board and found that there was a short at pins 5 and 6 (D+ and D-) of the CH340 chip, The easiest way to track this down was to remove the CH340 but the short was still there.

Scanning the schematic it looks like these 2 pins ONLY go go the USB connector so I fired up the heat gun and removed the USB-C connector. I could see no sign of a short before removing the connector but after doing so and cleaning the pads the short was gone. Re-soldering the USB-C and re fitting the CH340 and it is now working.

It looks like a nice little board and much smaller than I visualised.

Thank You Lizby for sending it to me to hack about with, I owe you a beer or 6.

Kind regards,

Mick (The big one)




.
Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<
 
lizby
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Joined: 17/05/2016
Location: United States
Posts: 3150
Posted: 03:24am 15 Mar 2024
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Glad you were able to get it working, Mick. Your investigations involved work beyond my skill level, and also beyond my patience level.

Four out of 5 working for me is still a bargain.
PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed
 
bigmik

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Joined: 20/06/2011
Location: Australia
Posts: 2914
Posted: 03:32am 15 Mar 2024
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Thanks Lance,

Truth be known it was NOT easy to change the USB connector, Removing it was easy enough with the heat gun but re-flowing the solder after cleaning the pads and pins of the connector didn't `quite' go to plan, using my microscope I found 2 pins did not `take' and I had to hit them with my iron, if not for the microscope and my 3x magnifying glasses I wouldn't be able to do it.

Regards,

Mick
Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<
 
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