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Mixtel90

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Joined: 05/10/2019
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Posted: 12:19pm 26 Aug 2025

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I'm attempting to lay out a 16-bit parallel SSD1963 board. I notice that the manual describes the ADC OPEN numbering thus:

Quote The range of pins are GP26, GP27, GP28, and GP29 for the RP2940 and
RP2350A. Plus GP55, GP56, GP57, GP58 on the RP2350B.

As well as the obvious typo for the RP2040, I don't understand how these numbers are derived for the RP2350B. There are no ADC channels below GP40 or above GP47 and there are no obvious pin numbers for the chip.

I'm guessing, and it's only a guess, that MMBasic remaps the RP2350 pins:
RP2040 - RP2350
GP26 = GP40
GP27 = GP41
GP28 = GP42
GP29 = GP43
GP55 = GP44
GP56 = GP45
GP57 = GP46
GP58 = GP47

I want to bring some ADC pins out, so it would be a good idea if I could find out which. :)

Mick

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

matherp
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Joined: 11/12/2012
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Posts: 10377

Posted: 12:27pm 26 Aug 2025

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Quote The range of pins are GP26, GP27, GP28, and GP29 for the RP2940 and
RP2350A. Plus GP55, GP56, GP57, GP58 on the RP2350B.

should be

Quote The range of pins are GP26, GP27, GP28, and GP29 for the RP2940 and
RP2350A. Plus GP40, GP41, GP42, GP43 on the RP2350B.

Edited 2025-08-26 22:28 by matherp

Mixtel90

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Posted: 12:37pm 26 Aug 2025

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So, I'm free to use GP30-37 as usual, as expected.

ADC0 on the RP2040 will be mapped to GP44(ADC4) and what would be ADC4/GP30 on the RP2340 if it existed will be mapped to ADC0(GP40) on the RP2350?

Mick

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

matherp
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Posted: 01:30pm 26 Aug 2025

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Quote ADC0 on the RP2040 will be mapped to GP44(ADC4) and what would be ADC4/GP30 on the RP2340 if it existed will be mapped to ADC0(GP40) on the RP2350?

In English?

Mixtel90

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Posted: 02:55pm 26 Aug 2025

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hehe...

Legal values for ADC OPEN are GP26, GP27, GP28, GP29, GP40, GP41, GP42 and GP43 for the RP2350B.

GP26-GP29 are ADC0-ADC3 on the RP2040 and, I assume, for MMBasic in general.

However, on the RP2350 the actual ADC numbers are ADC0 on GP40 up to ADC7 on GP47. There is no ADC0 on GP26. So, is GP26, when used in the ADC OPEN command on a RP2350 being re-mapped to GP44?

How do you use the ADC channels in MMBasic on the RP2350?
I assume
SETPIN GP44, AIN
will work and will connect to ADC4, however if you use the ADC OPEN command GP44 isn't legal and will throw an error.

Mick

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

matherp
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Location: United Kingdom
Posts: 10377

Posted: 03:15pm 26 Aug 2025

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The RP2350A is the same as the RP2040
The RP2350B has 8 ADC pins - GP40-GP47
All valid pins can be used by SETPIN AIN/ ? PIN(n)
The ADC OPEN command only supports 4 ADC channels. In the case of the RP2350B these are GP40-GP43. GP44-GP47 are not valid for ADC OPEN

Mixtel90

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Posted: 03:25pm 26 Aug 2025

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Ah, thanks. I understand now. :)

Mick

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

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