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hhtg1968
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Joined: 25/05/2023
Location: Germany
Posts: 139

Posted: 06:24am 28 May 2023

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seems very cool. i have such sd card adapters...

i do not understand the foto (i tried to zoom). the capacitor is between wich points? same for the resistor.

can i use the "normal" pins for ground and + from the sd card board after adding capacitor and resisitor?

can you create a symbolic explanation or picture?

Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 7938

Posted: 07:46am 28 May 2023

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Peter's standard SD card adapter beats them all for breadboard use. :)

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

paceman
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Joined: 07/10/2011
Location: Australia
Posts: 1329

Posted: 08:19am 28 May 2023

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I'm using the Catalex SD Card Adapter V1.1 direct to the PicoMite without any changes and it's all working fine. It's powered straight from the USB 5v going into the Pico. The SD module looks identical to the photo in Phill's last post but with the Catalex logo silkscreen. The buffer chip on it is a 14 pin PG8SD and the regulator is an HT1117 3.3.
looks like there are two versions 'in the wild' because there was a change in the design back about 2016. Seems the MISO line going back to the Pico had the buffer changed from being connected to Gnd to now being connected to the CS line. That apparently fixed people's issues, see here

Greg

Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 7938

Posted: 08:27am 28 May 2023

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[GRUMPY]
I don't like that site - it doesn't like my browser (Pale Moon) and I refuse to change to an insecure one simply because they can't write standard, compliant HTML.
[/GRUMPY]

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

phil99

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Joined: 11/02/2018
Location: Australia
Posts: 2642

Posted: 08:29am 28 May 2023

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Having 5V on the Pico pins is risky. Bypassing the regulator allows it to be powered from 3V3. The added components filter the supply to the SD card but aren't always needed.

Do NOT use 5V with this modification It will destroy the SD card.
Use 3V3 supply only.
Edited 2023-05-28 18:36 by phil99

IanRogers

Senior Member

Joined: 09/12/2022
Location: United Kingdom
Posts: 151

Posted: 08:33am 28 May 2023

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Remember I had the exact same problem.. I had to remove the level shifting altogether.
Mine however! was only resistors..

Even when I converted to 3v3 it still didn't work..

I'd give my left arm to be ambidextrous

Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 7938

Posted: 10:06am 28 May 2023

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It's a lot of fuss when you only need to solder a bit of male header onto a micro SDcard converter. :)

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

hhtg1968
Senior Member

Joined: 25/05/2023
Location: Germany
Posts: 139

Posted: 04:31pm 28 May 2023

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hi phil99. thank you so much. now - with 3.3v - i feel more secure.

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