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P2: No more FPGA?? — Parallax Forums

P2: No more FPGA??

So I've been gone for a while. I like to stop by from time to time and see how things are going around here. From what little I read, looks like the P2 might be a reality this year?

If so, I've got 2-3 projects already that could benefit from it. Two of them are going to be using FPGA's which, to be honest, isn't my cup of tea. So I'm "forcing" myself to learn them because I can't find a better way.

The specs (that I've read) on the P2 make me want to believe my days of FPGA work will be over. At least for a few more years.

I don't have anything against FPGA, BTW. I'm just overwhelmed by the documentation, tool sets, etc. that FPGA brings with it.


Anyway, if I may, I'd like to ask a few questions on the P2. Please forgive me if these have been asked ad nauseam.

1) Would a hobbyist like me be able to get my hands on a P2 this year? (2018)

2) What do you think will be the average street price for single units?

3) I'm really into building "retro" themed computers. It seems to me that a single P2 could quite literally be the RAM, ROM, GLUE and Video for a retro-themed computer running in the 1-4 MHz range. Does that sound practical? Meaning, could the P2 respond to external CPU's, RAM, etc. running as high as 8 MHz?

4) What video modes (if any) have been "baked in"? Can we expect easy VGA, NTSC, etc.? For me, 640x480 VGA with 256 colors over HDMI would be HIGH-END. Seems like the P2 should be able to handle that easily.

5) Seems like I read the P2 will have a DAC or two? If so, will producing audio (like maybe the way the Amiga does it) be as simple as streaming some bytes through the DAC? What kind of external audio components would be needed? I'm assuming some type of op-amp or something like that.


That's all for now.

Thanks so much for your help!

Comments

  • cgraceycgracey Posts: 14,133
    1) Maybe.

    2) Maybe $12.

    3) Totally!!!

    4) VGA, NTSC, PAL, at whatever resolution you want using 512KB internally, up to 190MHz pixel clock. Add a HyperRAM to get way bigger display memory.

    5) Every pin has a selectable 8-bit (16-bit with oversampling) 123-ohm or 990-ohm 3.3V DAC, which can also be a 75-ohm or 600-ohm 2.0V DAC. One pin can directly drive a TV baseband input. Three pins can be used to output R, G, and B, signals for VGA. A single pin in 16-bit DAC mode can make a great audio output - just use a 10uF series cap to remove DC bias, so that it's +/-1.65V.
  • Holy Smile. That's amazing!!

    So, I can literally take three pins and directly drive VGA with no R-2R ladder or anything like that? And, being 8-bit (or even 16!) I would get 256^3 colors?

    I cannot wait for this chip. And $12 sounds like an excellent price. Most of the FPGA's that I've been looking at were in the $8-$20 price and for what I need, severe overkill. But they don't have DAC's!
  • cgraceycgracey Posts: 14,133
    To get full 16-bit DAC function, you need 256x oversampling, so 16-bit samples can be output at up to 190MHz/256 = 742KHz.

    For video, you are limited to 8 bits per pixel clock, as there's no time for oversampling. If your pixel clock were 16 system clocks, you could custom code a 12-bit DAC output, where you oversample 16x to get another four bits. Lots of things are possible. Really, though, I've found that 8 bits is below the threshold of perception, already.
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