Noisy 595's

Testing/Troubleshooting
1

Hello all

I’m trying to drive a YM3526 chip with the LPC core. Software is all fine, I’ve tested my interface with LEDs so I know that’s good.

The program waits for a button to be pressed,then sends a series of numbers to 2 DOuts and a Tone should be heard through a loudspeaker. I’ve tried doing this with a load of switches and it works fine.

When I use the core and the software, the moment the 595’s in the DOut start changing value, noise is heard which doesn’t stop. The test tone is there but very faint.

Obvious thing to check is the power supply (USB powered), tried that, even using a battery, but its still the same.

Anyone got any suggestions what else to try?

Whilst I’m here anyone else working on a new synth/sound generating device with the new core?

Thanks

Sparx

2

Hi Sparx,

can´t help with the 595s, but regarding your question of someone else using the new core for audio output: have a look at Lee´s fine polyphonic sd sample player - which uses a DAC for output:

http://discourse.midibox.org/t/topic/15972

Greets,

Peter

3

Hi Peter

Yes I’ve seen that, not had much chance to play about with it yet, doesn’t the SD card have to be formatted in FAT?

I was thinking more along the lines of a Soundchip, such as SID, based synth.

Any help on the 595 noise is still requested!

Thanks

Sparx