2 ms·

> maybe just add GPIO to your PC By this I assume you mean “dangle an Arduino off the side”. Other than PI, what PC actually drives its own GPIO?

dangus 2y ago
https://www.adafruit.com/product/2264 https://www.adafruit.com/product/2264
throwup238 2y ago
> Other than PI, what PC actually drives its own GPIO? They used to be able to using parallel ports. When the controller was on the southbridge and accessible via DMA, you could get hard realtime even on Windows using device drivers and interrupts (pre-Vista, which changed the security model). There was software like Mach3 that could control a whole CNC off of a parallel port and lots of hardware companies used Wintel instead of SBCs or rolling their own PCB. San Francisco BART still uses parallel ports to control their trains and they have to hunt down for replacement parts on eBay [1]. Nowadays a PCIe GPIO card is at least a few hundred dollars and you're unlikely to get hard realtime guarantees unless it supports uploading custom firmware. Sharing functionality with the most common printer interface was a boon for PC GPIO but that's gone now. [1] https://news.ycombinator.com/item?id=32884814 https://news.ycombinator.com/item?id=32884814
- sirtaj 2y ago
  Back in the late 80s before ubiquitous digital audio, someone published a design for a sound card that used the parallel port and a super simple circuit with just some resistors. I found a similar recent one: http://jubatian.com/articles/building-an-lpt-dac/ http://jubatian.com/articles/building-an-lpt-dac/
  - epcoa 2y ago
    Not only that, it was a commercial product: https://en.wikipedia.org/wiki/Covox_Speech_Thing https://en.wikipedia.org/wiki/Covox_Speech_Thing
- supermatt 2y ago
  Can’t you just use a USB to parallel port adapter? Less than $5 on Aliexpress.
  - throwup238 2y ago
    No, the controller used to be part of the motherboard chipset in a way that allowed DMA access to GPIO registers (so the CPU didn’t need to actively bit bang the port, drivers could just fill a buffer and offload it to the hardware) and interrupts that had priority over all other processes. USB simply doesn’t work like that.

dangus 2y ago

https://www.adafruit.com/product/2264 https://www.adafruit.com/product/2264

throwup238 2y ago

> Other than PI, what PC actually drives its own GPIO? They used to be able to using parallel ports. When the controller was on the southbridge and accessible via DMA, you could get hard realtime even on Windows using device drivers and interrupts (pre-Vista, which changed the security model). There was software like Mach3 that could control a whole CNC off of a parallel port and lots of hardware companies used Wintel instead of SBCs or rolling their own PCB. San Francisco BART still uses parallel ports to control their trains and they have to hunt down for replacement parts on eBay [1]. Nowadays a PCIe GPIO card is at least a few hundred dollars and you're unlikely to get hard realtime guarantees unless it supports uploading custom firmware. Sharing functionality with the most common printer interface was a boon for PC GPIO but that's gone now. [1] https://news.ycombinator.com/item?id=32884814 https://news.ycombinator.com/item?id=32884814

sirtaj 2y ago
Back in the late 80s before ubiquitous digital audio, someone published a design for a sound card that used the parallel port and a super simple circuit with just some resistors. I found a similar recent one: http://jubatian.com/articles/building-an-lpt-dac/ http://jubatian.com/articles/building-an-lpt-dac/
- epcoa 2y ago
  Not only that, it was a commercial product: https://en.wikipedia.org/wiki/Covox_Speech_Thing https://en.wikipedia.org/wiki/Covox_Speech_Thing
supermatt 2y ago
Can’t you just use a USB to parallel port adapter? Less than $5 on Aliexpress.
- throwup238 2y ago
  No, the controller used to be part of the motherboard chipset in a way that allowed DMA access to GPIO registers (so the CPU didn’t need to actively bit bang the port, drivers could just fill a buffer and offload it to the hardware) and interrupts that had priority over all other processes. USB simply doesn’t work like that.