YM2149 with Logicstart Sigma delta dac.. possible?


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Hi all from London (UK.)

I'm having fun playing with the new version of Designlab (1.0.7). I have had a Papilio One 500K board with Logicstart Megawing for a while now but haven't had time to do much with it..

I am interested in sound synthesis and would like to know if it is possible to use the YM2149 sound chip component in a schematic with the Logicstart board using the Sigma Delta DAC to send the sound through the on board audio Jack as opposed to using an audio wing like shown in the example.

Is this possible?

Thanks for any help...

Steve.S :)

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I expect it's possible, I suspect it's even easy.  I don't know exactly how, because I haven't used DesignLab.


The main differences are going to be that the DAC is connected to a different pin on the FPGA, and that the audio wing is stereo (2 outputs) while that megawing is mono (1 output).  For the former, DesignLab probably has a way to select what board combination you're using (which is what determines the FPGA pin).  For the latter, it's probably just a matter of not using the "splitter" I see mentioned in the documentation; or else, I'd just take one of the outputs (left or right) and leave the other unconnected.

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Hello Steve,


It should be very easy to do with DesignLab, here are the steps I would recommend:


1) Start from the table of contents and find the existing project for the LogicStart MegaWing.

2) Open up that project and then save it to a new location so you can edit it.

3) Edit the circuit which will open up Xilinx ISE editor.

4) The existing circuit should have a Audio passthrough device connected to a DAC and the audio jack of the LogicStart MegaWing.

5) You should be able to replace the audio passthrough device with the ym2149.

6) Synthesize the design and you should be ready to load the circuit to the board and use any of the ym2149 examples.


Let me know how it goes, I can always record a screencast to help out if needed.



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Hi Jack.  :)

Thanks for the reply. I'm having great fun using the YM2149 library on its own but to get it working with the Logicstart would be excellent as I can use the Joystick , the ADCs and the switches to do some very cool shit. :)

OK. Ive opened up the MegaWing Logicstart sketch in Designlab (I'm using 1.0.7), saved it as another file and opened up the schematic in ISE. I've deleted the Audio passthrough and it's nets and connected the YM2149 to the wing and DAC fine. 

However, I seem to be getting compile errors like this:

ERROR:DesignEntry:20 - Pin "wishbone_in(61:0)" is connected to a bus of a   different width.ERROR:DesignEntry:20 - Pin "wishbone_out(33:0)" is connected to a bus of a   different width.

I'm not sure why... any ideas?

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thanks for the video. i followed all of the steps to the rule. however, i still get the same error. I'm using a papilio one 500k, the zpuino soft processor that appears on the schematic is the "hyperion" version even though i have my board selected as : papilio one 500k zpuino in the tools menu of designlab... :(

what could be going wrong???

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  • 2 weeks later...

Hi Jack. OK, back to it... I looked at your video again and realized that you were using the YM2149 symbol from the DESIGNLAB/LIBRARIES/zpuino_wishbone_peripherals. It doesn't show up for me. 

I've made a jing video showing you the process (there's no sound unfortunately but you should be able to follow..) 

So YM2149 doesn't show up in the list of symbols for the zpuino_wishbone_peripherals library folder even though the .sym and .vhd files are in the folder...

Also, the original design doesn't compile either. So even if I don't change anything, it still doesn't compile...

Here's the screencast link: http://screencast.com/t/60uVXY7A  I do hope you make sense of it and know what i'm doing wrong...



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Aha! The screencast does shed some light on the problem. I noticed you have some old .Papilio entries in the schematic editor from the old Papilio Schematic Library days. This video will show you how to get rid of them and clear this problem up:



Let me know how it goes.



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That did the trick! Thanks Jack it all seems to compile nicely now. I've uploaded the bitfile and the Logicstart sketch and all works as expected.  :D

One thing has hit me though... I can make sounds with the YM2149 library, but as it is now connected to the Sigma delta DAC, how do I go about sending the YM2149 output through it? (the DAC)...

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Yeah! I'm glad you are up and running now. :)


I'm not sure I follow your question about the DAC though... The YM2149 11 bit output should be connected to the 11 bit input of the DAC, the DAC should then turn that into a single channel analog output that can then be split into two analog channels that are then connected to the two audio jack outputs... The result is that when you play something using the YM2149 library you should hear it out of your audio channels...



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I'm using a Logicstart megawing with just the 1 audio output jack from the sigma delta. The schematic takes the YM2149 output and sends it thru the DAC and the DAC output is sent to the Audio block on the Logicstart. No audio splitter. Will it still work?


Ooh. Sack that. I've taken out the sigma delta DAC so I now just have the YM chip connected to wishbone slot 5. The YM output goes to the audio mixer and the mixer out to the Logicstart Audio input.

Working fine now.

Thanks again.  :D

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