SIDKick pico 2350DAC (SID 6581/8580-replacement) at PCBWAY

[wdsmith123]

Hi,
I'm getting some of the new 2350DAC boards built at PCBWay. They are asking for me to confirm the orientation of all the components. Unfortunately, there aren't enough pictures or design files posted either here or at PCBWay to help with that. Is it possible to at least post a closeup of the component side so they can check the orientation? Thanks!

[frntc]

This happens from time to time (it seems the person in charge for reviewing the order changes). Can you try to refer them to my own original order of the PCBs w/ assembly (they have it in their records) and tell them that they should do it exactly the same way?

(does your order include the LED on the top? then I'll dig out an image, it wasn't included in my order)

[wdsmith123]

I did point them to the community project. Not sure if that is sufficient. If you can share your original order number, I can also point to that. I am getting the LED, too. Not sure I need it, but why not? :)

[frntc]

ok, let's do it this way: ask them to contact me, and I'll try to explain that they should always follow my original order. Maybe that prevents the same questions again in the future :)

Here's the pin numbering of the LED (a WS2812B-B/W)...

[wdsmith123]

Thanks! I will respond with this and see what they say.

[bmmcwhirt]

I am also interested in ordering a few sets of boards and have a few questions. I thought it better to keep these in a single thread for anyone else who does a search.

1. When ordering from PCBWay to the US do you or anyone know what the import tax ends up being? PCBWay seems to only use FedEx and I've had issues with them trying to bill me outrageous amounts. ex: I placed a ~$150.00US order from Thonk (modular synthesizer modules), and FedEx tried to collect ~$200 in import taxes, which is more than the value of the order.

2. I am guessing that the 2350DAC version is still considered beta/order at own risk, since it's not been made official in the repository yet. Is that accurate?

3. Is there a Digikey or Mouser part number somewhere for the round header pins?

[bmmcwhirt]

That "coming soon" was only meant for the interactive BOM. I guess not many want to build it themselves...

Not sure if I got you: for the SKpico2350DAC you don't need a Pico2, everything's on the PCB.

I'd say for hobby projects mixing lead-free solder and leaded HASL doesn't matter, generally it's better to not combine leaded and lead-free.

I did not read closely enough and was assuming it was like the previous version. That actually makes these a much better deal.

[bmmcwhirt]

Also want to advise that you head frntc's suggestion and order the header pins and the WS2812B-B/W LED from LCSC. Even after shipping to the US and excise taxes it's cheaper than ordering from a US distributor. I ordered enough headers and LEDs for 40 boards for less than what it would have cost for parts for 10 boards from Digikey.

@frntc Thank you so much for your work on this, and your guidance. My boards have passed audit, but I'm still waiting on the build to pass so I can complete my order.

We'll see if my PCBWay order or my Founders Edition C64 arrives first.

[wdsmith123]

@frntc PCBWay finished assembly and asked again if the placement was correct. I am asking them to contact you. Hopefully they will and get my order shipped soon. :) I can also post the picture if you want to do it here.

They did get the LED correct with the picture you posted earlier.

[frntc]

They didn't contact me, you can post the picture here or (maybe better) send it via mail, the address in the source code

[wdsmith123]

I said the LED was OK since I could check it with your picture and the LED datasheet. I guess they took that as everything is OK and shipped the order. It's due tomorrow, so I will let you know what shows up and how I get along with it.

[wdsmith123]

They arrived and the first one at least seems 100% fine.

[wdsmith123]

Any way to add LED brightness or disable in case we decide it's too bright? :)

[wdsmith123]

And the flat pins I suggested above did work just fine and are really low profile.

[frntc]

Great! Are these the "long leg female headers"?

So far I've been too lazy to implement LED control in the config tool ;-)

[wdsmith123]

From above, these are (mouser part number 571-1544210-2). Just a long continuous strip that I cut to length. Already cut up a bunch, but the last little bit is the piece on the left.

[wdsmith123]

@frntc Hi again, I've noticed that these don't pass the "6581 Control Port" test of my diagnostic harness. I don't have any mice or paddles to test any other way. You can see from the pictures that the resistors are installed. I measured them to be 470ohms. A regular 6581 does pass. Any ideas?

Edit... I do have a Koalapad and it doesn't seem to be working. Checked with 6581 and it's good.

[frntc]

Adding an offset of 0x10 fails the 6581 test. Adding an offset of 0x20 passes the 6581 test. This is in RAW mode. Seems like a lot considering a 6581 doesn't need an offset. But I am far from a SID POT expert.

I guess it's ok. Mice and paddles should also work without the offset, and it's only required to make the diagnostic test happy ;-)

I don't have a Koala pad (nor know someone who has one). Reading X and Y should work (definitely if you do not use the smoothing options).

What you describe above is how paddle reading works! The SID doesn't read analog values, it looks for the voltage levels to pass a certain threshold. It might be that the 2V is already a bit too high, but I'd have to double check. Are there Koala pad schematics available?

[wdsmith123]

Thanks! Yeah, I plan on outfitting a bunch of C64 breadbins with these and selling them at VCF Southwest. I just needed to know all the ins and outs and make sure this assembly lot was done correctly. Too many breadbins in my stash have bad SIDs unfortunately.

So back to the Koalapad... I'm just now learning how the ADC in the SID works. I used to test much more fancy ADCs for a large company and this old one takes some getting used to. Also, there are no schematics for a Koalapad that I have been able to find. But if it's as you suspect, there are many ways to lower the starting voltage a bit. A large resistor to ground (4.7K maybe) at the 2350 pin would shift all values a bit lower (voltage divider with the 470 series resistor). If I understand correctly, that would also shift the offset down and may fix the diagnostic harness values? Maybe a tweak to the Koalapad itself if you think the 4.7K is a bad idea. I can take mine apart and draw out the schematic sometime. Let me know.

[wdsmith123]

@frntc I received a set of paddles and they work as expected with no offset in the setup menu. I think you are right that the trigger level is different between a real SID and a SIDKick. There are differences in the scope waveforms where the SIDKick always pulls down to 0V and then the RC ramps from there. The real SID actually pops up to ~1V and then the RC ramps from there. The MOS6581 datasheet says the trigger level for the ADC is VCC/2 and the returned values with a SID match that. I estimate that the trigger level for the SIDKick must be ~1V. The Pico datasheet says that a high is 2V, but that is the guarantee. I bet that the high is the low value of 0.8V plus the hysteresis of 0.2V.

I have another Koalapad on the way that needs some work, so I will try and make a schematic and send it over.

[bmmcwhirt]

Adding an offset of 0x10 fails the 6581 test. Adding an offset of 0x20 passes the 6581 test. This is in RAW mode. Seems like a lot considering a 6581 doesn't need an offset. But I am far from a SID POT expert.

I guess it's ok. Mice and paddles should also work without the offset, and it's only required to make the diagnostic test happy ;-)

I don't have a Koala pad (nor know someone who has one). Reading X and Y should work (definitely if you do not use the smoothing options).

What you describe above is how paddle reading works! The SID doesn't read analog values, it looks for the voltage levels to pass a certain threshold. It might be that the 2V is already a bit too high, but I'd have to double check. Are there Koala pad schematics available?

A full Koala Pad schematic has never been made public. This Lemon64 post has links to front and back sides of the board and some patent links.

[wdsmith123]

@bmmcwhirt

A full Koala Pad schematic has never been made public. This Lemon64 post has links to front and back sides of the board and some patent links.

Is the public clamoring for one? I've spent some time with mine and I think I have it all straight and in KiCad now. I can see where the 1V pedestal comes from when the Koala Pad is holding the POT lines low. I guess I could try removing the 1N4148 diodes or maybe finding some Schottky diodes instead?