4 ms·

RVPC: The 1-Euro RISC-V computer with VGA and PS/2

33 points by unwind 2y ago

DrNosferatu 2y ago
What about a little more expensive version with enough memory to handle VGA mode 13h? PS: If I’m not mistaken, this would mean a minimum of 256K video memory - so, say, another 256K for general RAM. So perhaps a 512K or 1MB system.
- DrNosferatu 2y ago
  The manufacturer’s similar chips max out at 64K - still it would make a more beginner-friendly project: Color makes a big difference in impact!
  - snvzz 2y ago
    >The manufacturer’s similar chips max out at 64K Perhaps these should be considered. 64KB is a world better than the 2K in the selected variant (CH32V003) in that micro-controller family.
    - brucehoult 2y ago
      As pointed out in my other comment, you can add vast amounts of extra functionality for very little cost, up to a Linux-running board with 64 MB RAM for $5. But that's not the point. The point is: what is the cheapest stand-alone usable computer you can make? "Usable" in the same sense as a ZX80 or Altair 8800 or Apple I of course, not in the sense of a modern computer. If you pay 50c for the CPU instead of 10c then you just increased the total cost by 50%.
      - snvzz 2y ago
        >If you pay 50c for the CPU instead of 10c then you just increased the total cost by 50%. True. But is the difference actually 5x? CH32V003 shouldn't be the only option.
- DrNosferatu 2y ago
  Perhaps the ESP32-C3?
- brucehoult 2y ago
  There is not a lot of pricing room between a $1 board with 10c 48 MHz 2 KB RAM chip (as here) and a $5 board with 1 GHz 64 bit 64 MB RAM board running Linux (Milk-V Duo). That gap is pretty much filled by boards using e.g. the ESP32-C3 with 400 KB RAM, running at 160 MHz. You cvan find quite a few of those for around $1.80. https://www.aliexpress.us/w/wholesale-esp32%2525252dc3-board.html https://www.aliexpress.us/w/wholesale-esp32%2525252dc3-board...
- snvzz 2y ago
  >to handle VGA mode 13h? While VGA is the interface used for the analog video signal, no attempt is being made to emulate the old "VGA controller".
- DrNosferatu 2y ago
  I guess you could always get the Agon Light, but that’s 50€! The ESP32-C3 can be had for under 2€. …and a killer app for such a nano computer would source ports of people’s favorite retro games ;)
poulpy123 2y ago
What do you plug on VGA and PS/2 nowaday ?
- snvzz 2y ago
  A PS/2 Keyboard and a VGA monitor. Alternatives include e.g. a PS/2 compatible USB keyboard via passive adapter, and a HDMI monitor through an OSSC (Open Source Scan Converter).
AstroJetson 2y ago
/sigh, I just tossed a stack of PS2 keyboards and two monitors that took VGA into the electronic recycle station. "Nothing does PS2 anymore, and everything is HDMI" now ring hollow in my head. So I'm going to buy a $1 computer and $30 worth of adaptors to play with it. :-)

33 points by unwind 2y ago

What about a little more expensive version with enough memory to handle VGA mode 13h? PS: If I’m not mistaken, this would mean a minimum of 256K video memory - so, say, another 256K for general RAM. So perhaps a 512K or 1MB system.

DrNosferatu 2y ago
The manufacturer’s similar chips max out at 64K - still it would make a more beginner-friendly project: Color makes a big difference in impact!
- snvzz 2y ago
  >The manufacturer’s similar chips max out at 64K Perhaps these should be considered. 64KB is a world better than the 2K in the selected variant (CH32V003) in that micro-controller family.
  - brucehoult 2y ago
    As pointed out in my other comment, you can add vast amounts of extra functionality for very little cost, up to a Linux-running board with 64 MB RAM for $5. But that's not the point. The point is: what is the cheapest stand-alone usable computer you can make? "Usable" in the same sense as a ZX80 or Altair 8800 or Apple I of course, not in the sense of a modern computer. If you pay 50c for the CPU instead of 10c then you just increased the total cost by 50%.
    - snvzz 2y ago
      >If you pay 50c for the CPU instead of 10c then you just increased the total cost by 50%. True. But is the difference actually 5x? CH32V003 shouldn't be the only option.
DrNosferatu 2y ago
Perhaps the ESP32-C3?
brucehoult 2y ago
There is not a lot of pricing room between a $1 board with 10c 48 MHz 2 KB RAM chip (as here) and a $5 board with 1 GHz 64 bit 64 MB RAM board running Linux (Milk-V Duo). That gap is pretty much filled by boards using e.g. the ESP32-C3 with 400 KB RAM, running at 160 MHz. You cvan find quite a few of those for around $1.80. https://www.aliexpress.us/w/wholesale-esp32%2525252dc3-board.html https://www.aliexpress.us/w/wholesale-esp32%2525252dc3-board...
snvzz 2y ago
>to handle VGA mode 13h? While VGA is the interface used for the analog video signal, no attempt is being made to emulate the old "VGA controller".
DrNosferatu 2y ago
I guess you could always get the Agon Light, but that’s 50€! The ESP32-C3 can be had for under 2€. …and a killer app for such a nano computer would source ports of people’s favorite retro games ;)

poulpy123 2y ago

What do you plug on VGA and PS/2 nowaday ?

snvzz 2y ago
A PS/2 Keyboard and a VGA monitor. Alternatives include e.g. a PS/2 compatible USB keyboard via passive adapter, and a HDMI monitor through an OSSC (Open Source Scan Converter).

AstroJetson 2y ago

/sigh, I just tossed a stack of PS2 keyboards and two monitors that took VGA into the electronic recycle station. "Nothing does PS2 anymore, and everything is HDMI" now ring hollow in my head. So I'm going to buy a $1 computer and $30 worth of adaptors to play with it. :-)