wiretap wrote on 2021-08-23, 19:55:

I don't think there is enough room. I mean it may be possible if you're super good at placement & routing and use 0402 size caps/resistors. But I didn't check any assembly services to see if they even have these components available. Some are pretty specialized.

But, anyone is free to give it a go, as the project files are all there and it is open source.

Maybe add an extra board on top, with an arduino, two push button or a rotary encoder, and maybe a tiny oled display 😉

though I took a look at the datasheet of the Si5351 and wonder what clock speed will be output at first powerup without any data in the NVM of the Si5351 ?

I get the impression that a configuration will have to be written, which can afterwards be altered using the I²C bus, though if set at 50MHz, it won't be usable in an old 386sx16, and since it's a OTP NVM...

I'm not sure what would be there initially. Probably null. What I would do is program it to the original oscillator specification for the motherboard, then just write values to its RAM to change frequencies afterwards. That could be done with a rotary knob or buttons and an arduino with a screen/LEDs. You would essentially be selecting scripts to run to program oscillator output #1.

It has been nearly 3 years since this thread began. I have a few questions:

Has anyone assembled the variable full can oscillator version? If so, how did it work out, especially at high frequencies, e.g. 80-110 MHz?

Looks like the gerbers are 2 layers. Would there be any benefit in adding an inner ground layer?

Was JLCPCB able to source the components and do the assembly?

Has anyone priced the components yet? I noticed that Adafruit sells the Si5351A for only $7.95. If the components from wiretap's full can model are all to the Si5351A, I was wondering if it would be cheaper to buy the Adafruit unit and transplant all the components onto wiretap's PCB.

PCB's are cheap, $4.50 for 30 pieces, or $2 for 5 pieces.

Thanks.

I know at least one person on an Amiga discord group I'm on made one like a year ago and it worked. (variable model) No idea who it is though.. I just remember someone thanking me.

weedeewee wrote on 2021-08-23, 20:15:

Maybe add an extra board on top, with an arduino, two push button or a rotary encoder, and maybe a tiny oled display ;-) […]
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wiretap wrote on 2021-08-23, 19:55:

I don't think there is enough room. I mean it may be possible if you're super good at placement & routing and use 0402 size caps/resistors. But I didn't check any assembly services to see if they even have these components available. Some are pretty specialized.

But, anyone is free to give it a go, as the project files are all there and it is open source.

Maybe add an extra board on top, with an arduino, two push button or a rotary encoder, and maybe a tiny oled display 😉

though I took a look at the datasheet of the Si5351 and wonder what clock speed will be output at first powerup without any data in the NVM of the Si5351 ?

I get the impression that a configuration will have to be written, which can afterwards be altered using the I²C bus, though if set at 50MHz, it won't be usable in an old 386sx16, and since it's a OTP NVM...

Stacking a micro on top of an oscillator circuit is a great way to trash your clock signal quality

feipoa wrote on Yesterday, 15:31:

Si5351A for only $7.95

Si5351A devboards are <$2 on aliexpress, its a $0.5 part in bulk. You cant program its NVM, SL/Skyworks keep it under NDA and last time I checked no one knew how to do it on the open internet, thus it needs small micro ($0.5-1 whatever) on board to program initial clock values.

Programming via I2C shouldn't be a problem for me. I have an old EtherTen (arduino based) from 2010 that I keep around for situations like this. https://www.freetronics.com.au/products/etherten

The price for the Si5351A on AliExpress is irresistible, at $1 USD with free shipping. EDIT: Its only $1 if you are new to aliexpress; $2.22 otherwise.

I did add up the values from the BOM, placed into digikey, then converted to USD. For enough components to assemble 10 units, it would cost (after tax and shipping), $64.25 USD. That's $6.42 USD for components for 1 oscillator unit. With AliExpress, I can get the components for $1 and transplant them to wiretap's PCB ($2).

Thus, $3 USD is the unit cost.

Unless you guys think the quality of the parts from Aliexpress will be substantially lower than what is on digikey and effect oscillator noise, reliability, etc.?