Problem with turn devices on and off with parallel port !!!!

[salem01]

i have a project which use the parallel port to control any device by turn it on or off but i still have a problem ....

when the computer running after shutdown or restart usualy the pins on the parallel port are active which means the devices will be on :x

so i think i have to connect the parallel port to IC or some thing which keep the port off untel i connect by my program which allows me to control all devices

thats all

 

[kubeek]

I think the best solution is to first reset the port before sending data, because windows usually set all pins to high on start-up.
Another solution would be to use negative logic - high on the port means switched off.
If you are not using any self-written program, try to ask some programmer, it is not too hard to make a small program like this.

 

[salem01]

thanks alot Mr.kubeek

but you now i use a program by me and i have some good experince with programming but the problem is no one can keep the port's pins off when computer starting in boot because that comes from BIOS and all what i can do is control the port after the windows starting but through booting i can't do any thing .....



if i use the negative logic it means also the devices will be start ON and OFF without control because the BIOS sending signal and stop sending it ...

the only solution is make a small circuit with IC include In and Out which usualy be OFF but when my program start it will be connected with IC by DLL file as a driver like Printer , Scanner , Camera , ... all kinds og computer devices :?: :!: :?: :!: :?: :?: :?:


Thank You So Much

 

[salem01]

thanks alot Mr.kubeek

but you now i use a program by me and i have some good experince with programming but the problem is no one can keep the port's pins off when computer starting in boot because that comes from BIOS and all what i can do is control the port after the windows starting but through booting i can't do any thing .....



if i use the negative logic it means also the devices will be start ON and OFF without control because the BIOS sending signal and stop sending it ...

the only solution is make a small circuit with IC include In and Out which usualy be OFF but when my program start it will be connected with IC by DLL file as a driver like Printer , Scanner , Camera , ... all kinds og computer devices :?: :!: :?: :!: :?: :?: :?:


Thank You So Much

 

[Nigel Goodwin]

Use the serial port, and send the data out to a PIC, the PIC then switches pins high and low in response to the data sent from the computer.

 

[mstechca]

Use the serial port...

:lol: :lol:

Nigel, you are so funny. You normally go for the latest technology and now you tell the guy to use a serial port which to many computers, is obsolete.

I still think there may be a solution with the parallel port. Doesn't the INIT pin do something when the computer is first turned on?

if not, how about embedding an activation code in your circuit, and write a driver that activates the device. That way, you won't have to worry what operating system is doing to your port. When the driver begins, it send out the activation code to the parallel port. It could even be a 1-byte activation code (which is the easiest), or go nuts and use all of the lines that are meant for output. I can't remeber them all, but there are more than 8.

 

[akg]

if not, how about embedding an activation code in your circuit, and write a driver that activates the device. That way, you won't have to worry what operating system is doing to your port. When the driver begins, it send out the activation code to the parallel port. It could even be a 1-byte activation code (which is the easiest), or go nuts and use all of the lines that are meant for output. I can't remeber them all, but there are more than 8.

using serial will be much more easier than this

 

[kubeek]

And what about to use a buffer with write_enable switch on the interface, and switch in on after the computer has booted?
Or do all the pins stay high after starting the computer, or just the 8 data pins?

 

[mstechca]

using serial will be much more easier than this

and it is slower.

I'm sure the poster wants complete bytes.

by the time you send 8 bytes down serially and decode them back, the speed will be 8x slower on the serial line if the baud rate coming out of the parallel and serial ports are the same, the flow control is the same, and the stop and start bits are the same (and every other property related to speed).

 

[Nigel Goodwin]

using serial will be much more easier than this

and it is slower.

I'm sure the poster wants complete bytes.

by the time you send 8 bytes down serially and decode them back, the speed will be 8x slower on the serial line if the baud rate coming out of the parallel and serial ports are the same, the flow control is the same, and the stop and start bits are the same (and every other property related to speed).

A fine example of inaccuracy and half truths!.

Standard asyncronous serial is TEN bits, 8 data bits, a start bit and a stop bit - neither start bits, stop bits, or baud rate, apply in any way to a parallel port. So assuming it's clocked out at the same rate, a parallel port 'may' be ten times faster.

However, it VERY unlikely that speed is going to be a problem, with a serial port running at 115Kbps you can switch the output pins 11,500 times a second, which is faster than you need for almost all purposes.

 

[salem01]

serial port with PIC IC …
That’s ok but which PIC I can use and how ?
Which pins in the port I have to connect with ?
What are the codes from vb6 to send through the serial port ?


Please tell me HOW? If you know



Thank you so much for all

 

[akg]

serial port with PIC IC …
That’s ok but which PIC I can use and how ?
Which pins in the port I have to connect with ?
What are the codes from vb6 to send through the serial port ?
Please tell me HOW? If you know
Thank you so much for all

Hope u have seen my replay about LPT in ur other thread.

see this tut . it is from Nigel's pic tutorial
it includes more than u need , also use the ICs datasheet.

 

[zhi_yi]

hi salem, how about you use one of the pin from parallel port as "output enable"?? for example, u use the "data register" of the parallel port to switch your devices ON and OFF, you can use one pin of status register as input, if the status register receive logic that is differ from what is normally set by computer after start up, then your devices is active, so one of the status register work as switch, can it be possible for your circuit?

 

[dratomic]

Here I thought I'd be clever and zhi_yi beat me to it.
Guess I should read further before being so smart.
You beat me to the suggestion a month ago.

Ah well

https://groups.yahoo.com/groups/YoungScientistsClub

Need Free components? We help whoever can't afford them with
whatever we have in stock or storage. Why? Why not? Thats how
I started. Someone helped me.

 

[anilmudulakar]

i think i have a soultion for u...
just download userport software from the internet.....after installing the port will be only in off condition after restart and even u can control in WINXP also... i hope this will solve ur problem.

http://www.seed-solutions.com/gregordy/Amateur Radio/Experimentation/N2PKVNA/UserPort.htm#Download

 

[StopGo]

One solution that I dont think has been offered yet is to use a pulsed "watchdog" circuit. This could be used to generate a signal that keeps all your devices turned off until the PC had output several seconds of pulses on one of the parport pins.

This watchdog circuit can be built out of a couple of capacitors, diodes a resistor and a FET, arranged so that each pulse on an output from the port transfers a fixed ammount of charge from the first cap into the cap of an RC time delay circuit.

Hope this makes sense.