TDA1543 DAC-based I2S board for LPC17?

Design Concepts
1

Hi,

just bought a couple of TDA1543 DAC chip from eBay. Can anyone give me any tips on utilising these chips to give stereo audio output from a LPC17-based Core board? I notice TK has used one for his MIDIBox Speech Synth project, and there is mention of I2S audio output in some of the MIOS32 tutorial applications, but I haven’t been able to find any newbie-friendly documentation on getting them to work. I’m sure the circuitry required is probably very simple, but I’d love to see a circuit diagram or matrix/vero board layout for a basic I2S audio output board.

Cheers,

a|x

2

Hi,

I will draw a schematic soon, but I will be too busy with other things this week…

Best Regards, Thorsten.

3

Thanks TK, that’s great! I’m still waiting for the components now, anyway, so there’s no massive hurry.

Cheers,

a|x

4

My TDA1543 chips arrived the other day, so was wondering if you’d had a chance to draw up that circuit-diagram/layout for the I2C board, TK.

No huge hurry- I have plenty of other things to keep me occupied at the moment. Just thought I’d mention it.

Cheers,

a|x

5

I will have more sparetime this weekend, and the weather forecast is bad as well :wink:

Best Regards, Thorsten.

6

I will have more sparetime this weekend, and the weather forecast is bad as well :wink:

Best Regards, Thorsten.

Perfect for diagram-drawing then :wink:

Thanks Thorsten.

a|x

7

Hi Thorsten. Hope you had a good weekend. Did you have a chance to do a quick diagram for this?

Cheers,

a|x

8

Yes - after two hours trying to install/patch a newer xcircuit version, I gave up and created these schematics with the old version:

http://www.ucapps.de/mbhp_i2s.html

Best Regards, Thorsten.

9

Sidenote: I found that a bigger cap (1000-2220uF) between Vcc and Ground (C3) can help reduce noise dramatically with the TDA1543.

10

Thanks very much TK, that’s excellent! Sorry about your upgrade hassles.

a|x

11

Sidenote: I found that a bigger cap (1000-2220uF) between Vcc and Ground (C3) can help reduce noise dramatically with the TDA1543.

thanks for the input! :slight_smile:

I replaced C3 by 1000 uF, and added C4=100 nF

Best Regards, Thorsten.

12

Interesting. However I just looked at the PCM1725 data sheet via Mouser and it says it is not recommended for new designs. Stock up now I suppose…

13

Quick question:

testing the simple i2s Synth project in trunk/apps/tutorials/024_i2s_synth with my newly-soldered DAC board. Is velocity supposed to be mapped to OSC frequency? I seem to get a different frequency with the same note at different velocities (plus massive amounts of aliasing distortion, too), but if I press each key realllly softly (giving a velocity of 1, I guess), it sounds as expected- ie a clear basic sawtooth wave, tracking the keyboard. Is this expected? Can’t see anything in the code comments to suggest this is how it’s supposed to work. If not, could it be a hardware error somewhere on my DAC board?

a|x

14

Interesting. However I just looked at the PCM1725 data sheet via Mouser and it says it is not recommended for new designs. Stock up now I suppose…

Hi,

I see a similar notice on the TI website for the PCM1725

"Not Recommended for New Design (NRND)

Replaced By PCM1754 – The device has the SAME FUNCTIONALITY as the compared device, but is not pin-for-pin equivalent and may not be parametrically equivalent."

Anyways, thank you for this community. Still learning about all that is happening here.

15

Hi,

I see a similar notice on the TI website for the PCM1725

"Not Recommended for New Design (NRND)

Replaced By PCM1754 – The device has the SAME FUNCTIONALITY as the compared device, but is not pin-for-pin equivalent and may not be parametrically equivalent."

Anyways, thank you for this community. Still learning about all that is happening here.

It might have something to do with the fact that fuzzylizard’s post is more then a year old :wink: