Post by thread:[OT] Re: Visual Basic and Port Control

I wrote a Visual Basic program to sample an IO port every 10 mS. The program seems to miss samples when other programs are running in Windows. Is there a way of reading an IO port in VB without missing samples ? Thanks. On 26 Jul 2002 at 10:30, Tim McDonough wrote: > I just finished a project where I needed to provide a Windows based > utility that would in-circuit program the EEProm in a non-PIC device. I > wrote the PC application using VB6 and an IO Active X control from JS > Payne (http://www.jspayne.com). The IO control gives you all sorts of > individual control of the serial and parallel port lines and is quite > well documented. > -------------------- Marcelo Puhl spam_OUTmarkTakeThisOuTcpovo.net http://py3ss.cjb.net -------------------- -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

On Fri, 26 Jul 2002 14:25:44 -0300, Marcelo Puhl wrote: >I wrote a Visual Basic program to sample an IO port every 10 mS. >The program seems to miss samples when other programs are running in >Windows. > >Is there a way of reading an IO port in VB without missing samples ? The IO Control I used will sample the state of the serial ports or the parallel port each time the appropriate function is called. It also includes it's own Timer-like object that works down to 1mS. Windows is far from a real-time operating system. You have little control over how long other programs hog the CPU when they are running. In my experience an I/O card or external device with its own micro is the best way to collect/control time critical things. Then you can hand the data or results off to Windows when it decides it's ready to talk with your device. Tim -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

If you just use the built in COM control, you dont have to sample at any rate, you will just get an MS_COMM event when anything is received from the port. Then, you can use the CTR/DTR lines as a control if you realy need one. I have a device at the other side of a VB program and just shoot serial data back and forth (use the interupt in the PIC to know when the PC sent something). I use 19.2 and have no problems with synch or missed chars (not that i know of anyway ;) ) Shawn {Original Message removed}

On Fri, 26 Jul 2002 14:02:52 -0400, Shawn Yates wrote: >If you just use the built in COM control, you dont have to sample at >any rate, you will just get an MS_COMM event when anything is >received from the port. Then, you can use the CTR/DTR lines as a >control if you realy need one. I have a device at the other side of >a VB program and just shoot serial data back and forth (use the >interupt in the PIC to know when the PC sent something). I use 19.2 >and have no problems with synch or missed chars (not that i know of >anyway ;) ) I hope I haven't confused anyone here. In my application I am not using the serial port for any of its "normal" features. In conjunction with the IO control I mentioned it's an easy way to have a few individually controllable I/O lines on the host PC. The PC isn't hooked to a conventional RS232 port. Tim -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

I don't know about VB but for VC++ you have to use multimedia timers to get high resolution timer events (down to 1ms). Ruben {Quote hidden}> I wrote a Visual Basic program to sample an IO port every 10 mS. > The program seems to miss samples when other programs are running in > Windows. > > Is there a way of reading an IO port in VB without missing samples ? > > Thanks. > > On 26 Jul 2002 at 10:30, Tim McDonough wrote: > > > I just finished a project where I needed to provide a Windows based > > utility that would in-circuit program the EEProm in a non-PIC > > device. I wrote the PC application using VB6 and an IO Active X > > control from JS Payne (http://www.jspayne.com). The IO control gives you > > all sorts of individual control of the serial and parallel port > > lines and is quite well documented. > > > > -------------------- > Marcelo Puhl > .....markKILLspam@spam@cpovo.net > http://py3ss.cjb.net > -------------------- > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > ============================== Ruben Jönsson AB Liros Elektronik Box 9124, 200 39 Malmö, Sweden TEL INT +46 40142078 FAX INT +46 40947388 rubenKILLspampp.sbbs.se ============================== -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

High resolution timer isn't the issue. Missed events are. On 27 Jul 2002 at 1:42, Ruben Jönsson wrote: {Quote hidden}> I don't know about VB but for VC++ you have to use > multimedia timers to get high resolution timer events > (down to 1ms). > > Ruben > > > I wrote a Visual Basic program to sample an IO port every 10 mS. > > The program seems to miss samples when other programs are running in > > Windows. > > > > Is there a way of reading an IO port in VB without missing samples ? > > > > Thanks. > > > > On 26 Jul 2002 at 10:30, Tim McDonough wrote: > > > > > I just finished a project where I needed to provide a Windows based > > > utility that would in-circuit program the EEProm in a non-PIC > > > device. I wrote the PC application using VB6 and an IO Active X > > > control from JS Payne (http://www.jspayne.com). The IO control gives you > > > all sorts of individual control of the serial and parallel port > > > lines and is quite well documented. > > > > > > > -------------------- > > Marcelo Puhl > > .....markKILLspam.....cpovo.net > > http://py3ss.cjb.net > > -------------------- > > > > -- > > http://www.piclist.com hint: PICList Posts must start with ONE topic: > > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > > ============================== > Ruben Jönsson > AB Liros Elektronik > Box 9124, 200 39 Malmö, Sweden > TEL INT +46 40142078 > FAX INT +46 40947388 > EraseMErubenspam_OUTTakeThisOuTpp.sbbs.se > ============================== > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads