DOS ain't dead

controlling GPIOs from DOS (Announce)

posted by Damien, 05.12.2013, 19:55

> Regular parallel ports can easily exceed 1 Mbps, so it doesn't sound like
> speed is your issue -- you don't need an "improved" parallel port in that
> sense. It sounds like your main concern is the interface, not the speed.
>
> Does it need to be an I/O interface, or would the regular INT 17h BIOS
> interface for the parallel port work for you? Of course the INT 17h
> interface only allows for a byte at a time to be transferred instead of a
> dword, but you could easily create a function/procedure to handle that
> automatically (the "simple" interface you're looking for could be a
> function call, could it not?).
>
> In my USBPRINT program, I've added some INT 17h extensions to allow for the
> transfer of entire blocks of data (not just a byte or even a dword at a
> time), and also to allow for data to be received from the device instead of
> just being sent. The data in the reverse direction (from the device to the
> computer) must be sent in nibble mode (IEEE 1284 specification), so isn't
> as fast as the forward direction, but it does work. The main purpose of
> USBPRINT is to be a driver for USB printers and USB-to-parallel converter
> cables, but also adds some enhancements to regular parallel ports. It may
> be able to help you with your quest.

By 1 Mhz I mean that each access to the port (read or write) is 1 µs. so it corresponds to 8Mbps in your speed system measurements.
I am not looking for big data transfer, but I need to access the "real world" quite often and with a short cpu time. At the present time I use paralle port with "inportb(0x378)" instruction, and it takes about 1us. I would prefer if it took less time, for example 0.1us. But I don't know much about efficient low-level access.

For example I don't know how to use int 17h, I guess I shall try to understand it.

Complete thread:

• controlling GPIOs from DOS - Damien, 03.12.2013, 22:54 (Announce)
  • controlling GPIOs from DOS - RayeR, 04.12.2013, 01:08
    • controlling GPIOs from DOS - Damien, 04.12.2013, 21:27
      • controlling GPIOs from DOS - RayeR, 05.12.2013, 01:07
  • controlling GPIOs from DOS - bretjohn, 04.12.2013, 17:26
    • controlling GPIOs from DOS - Damien, 04.12.2013, 21:38
      • controlling GPIOs from DOS - bretjohn, 05.12.2013, 03:18
        • controlling GPIOs from DOS - RayeR, 05.12.2013, 10:59
          • controlling GPIOs from DOS - bretjohn, 05.12.2013, 16:28
            • controlling GPIOs from DOS - RayeR, 06.12.2013, 03:09
              • controlling GPIOs from DOS - Zyzzle, 06.12.2013, 07:57
          • controlling GPIOs from DOS - Damien, 05.12.2013, 19:45
        • controlling GPIOs from DOS - Damien, 05.12.2013, 19:55
          • controlling GPIOs from DOS - RayeR, 06.12.2013, 03:17
            • controlling GPIOs from DOS - Damien, 07.12.2013, 00:39
              • controlling GPIOs from DOS - RayeR, 08.12.2013, 03:01
          • controlling GPIOs from DOS - bretjohn, 09.12.2013, 05:15