Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Comm and VCSP port twiddling controls sigs
#1
I am back playing with comm ports again.  Way back in the old days it was possible to talk using inp and outp  to twiddle RTS n DTR.  As well as read DTR n CLS.  Nowadays it's not possible to get to those signals.  It's all because of VCSP (virtual comm serial port).  It's possible to have 255 serial ports in windows.  In the original PC comm ports maxed at 4 physical ports.  Now the VCSP port could be a alternative to a 8250 comm chip.  Or even not a comm port but a Ethernet serial interface device.

I am trying to test the above control signals, to identify bad ports (combination of loop back and such).  I need a way to set and read the control signals.

I suck at DLL interfacing with QB64.  Which is where I assume be VCSP signals need to be accessed.

Any help here maybe ?
Reply
#2
(06-08-2023, 12:12 PM)doppler Wrote: In the original PC comm ports maxed at 4 physical ports.  Now the VCSP port could be a alternative to a 8250 comm chip.  Or even not a comm port but a Ethernet serial interface device.
What kind of hardware are you using, are you sure it gives you that level of control? I didn't think the 8250 or any of the other UART controllers allowed you to directly set/read those signals, rather only the parallel port gave that kind of control. If your hardware can't do it then the software aspect doesn't really matter.
Reply
#3
(06-08-2023, 05:08 PM)DSMan195276 Wrote:
(06-08-2023, 12:12 PM)doppler Wrote: In the original PC comm ports maxed at 4 physical ports.  Now the VCSP port could be a alternative to a 8250 comm chip.  Or even not a comm port but a Ethernet serial interface device.
What kind of hardware are you using, are you sure it gives you that level of control? I didn't think the 8250 or any of the other UART controllers allowed you to directly set/read those signals, rather only the parallel port gave that kind of control. If your hardware can't do it then the software aspect doesn't really matter.
Yes you could get to those control sigs.  The base ports were 3F8, 2F8 and 3E8, 2E8 for serial ports.  Parallel ports had 3BC monochrome card and 278, 378 parr only cards.  Win98 flavor you could go directly using INP(port) and outp(port).  You had to know the internals to the 8250 or 16550 chips.  When win2000 (winNT) started.  Direct access was impossible or use PortIO driver.  PortIO is possible but you have to know the internals of the VCSP device.  Too many flavors there.  So a comm interface DLL now must be used.  By the interface those pins or the equiv function of the pins are accessible.  That is what I need to get to.  RS232 has not changed much in it's function.  Only the hardware has changed.
Reply




Users browsing this thread: 1 Guest(s)