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Grogster

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Posted: 12:53am 06 May 2023

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The latest FW supports the 4822 DAC chip, which seems to be a lovely additional feature to have.

Can you use this with PLAY WAV, or is it only designed to work with PLAY SOUND or PLAY TONE?

I have seen plenty of examples of using PLAY SOUND and PLAY TONE in the threads, but no mention of being able to play WAV files off the SD card via this chip.

Yes you can?
No you can't?

Assuming you can, the manual mentions that WAV files have to be 8-bit sampling.
With the 12-bit DAC chip, can I assume that WAV files can now have 12-bit sampling?

Yes?
No, must remain at 8-bit?

Peter also mentions in one of his posts about the DAC, that it uses a bit more of the grunt of the 2040 processor then the passive L/C filter method does. ROUGHLY how much more CPU does using the DAC involve?

Smoke makes things work. When the smoke gets out, it stops!

matherp
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Posted: 06:55am 06 May 2023

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The DAC can do everything the normal audio can including playing FLAC files
WAV files have always been able to be up to 16-bit. This is then truncated to 12 for the DAC and just over 11 for the PWM audio - don't know where 8-bit came from
The difference in processing is just that the audio interrupt routine has to output via SPI which takes a finite time. I haven't quantified this impact

Grogster

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Posted: 07:49am 06 May 2023

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Thanks very much, Peter.

8-bit thing came from manual(5.07.06, Rev 1), page 112:

Perhaps the manual is simply out of date now with respect to the new DAC feature etc.

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Geoffg

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Posted: 08:49am 06 May 2023

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It is and will be fixed. Thanks.

Geoff Graham - http://geoffg.net

Grogster

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Posted: 08:55am 06 May 2023

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YAY!

Smoke makes things work. When the smoke gets out, it stops!

Quazee137

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Posted: 09:23am 06 May 2023

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Is the DAC code in the picomite ?

I see a player with the disk jacket on the display under it the wave form
scrolling across the bottom. on the side or top is music selection gui's.

The SD card would have the disk/song image and wav files with same name
just the extensions different.

this is just FUN stuff

Quazee137

1.8", 2.4" or even a round display

with the sd card and audio I could give instructions on setting up the
controllers.

Oh this is getting sooo FUN

Edited 2023-05-06 19:38 by Quazee137

Grogster

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Posted: 09:49am 06 May 2023

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My understanding is that that FW now streams the digital audio information to the DAC chip, and it processes it.

The DAC is EXTERNAL to the PicoMite and MMBASIC, although it is ultimately controlled by it. IE: The DAC chip itself contains the DAC routines, and all it needs is a serial data stream, which is what the latest MMBASIC provides.

So, NO - The DAC code will not be in MMBASIC as I see it, it just FEEDS the extenal DAC chip, which then does the job of interpreting it.

That's my understanding, anyway.

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JohnS
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Posted: 10:08am 06 May 2023

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I think it's set up by such as

SETPIN GP23,OFF: SETPIN GP24,OFF: OPTION AUDIO SPI GP24, GP22, GP23

John

Quazee137

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Posted: 10:26am 06 May 2023

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What I am asking is does/can the Picomite firmware allow use of the DAC
or just the PicomiteVGA ?

Quazee137

It does just looked at the "NEW manuals" Had old picomite manual on desktop.

Mixtel90

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Posted: 10:42am 06 May 2023

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The DAC doesn't actually do any decoding, as such, it (simply!) outputs some digital registers to analogue pins - very much like the VGA output on the green pins but with 12 virtual pins instead of two physical ones.

The Pico is streaming data to the DAC via SPI (there's no MISO as there's no point in trying to read from a DAC). Each time the registers are updated a pulse on LDAC updates the two analogue outputs simultaneously so it's glitch-free. Very neat.
.

Mick

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

Quazee137

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Posted: 12:26pm 06 May 2023

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What I was asking is

PLAY WAV file$[,interupt]
using the DAC like in peters new board
that is using PicomiteVGA firmware.

if connecting up the DAC to a Picomite will this work?
PLAY WAV file$[,interupt]

as JohnS showed
SETPIN GP23,OFF: SETPIN GP24,OFF: OPTION AUDIO SPI GP24, GP22, GP23

it does.

Quazee137
Edited 2023-05-06 22:30 by Quazee137

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