reading from a parallel port

[smercurio_fc]

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@Baji wrote:

 smercurio_fc wrote

Also, have you verified that you parallel port is 5V tolerant? Many computer nowadays have 3V parallel ports. 

I like to know, what is 5V tolerant and 3V tolerant. do u mentioned TTL as 5V and CMOS as 3V or something else, please forward the infos or related links.

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It's pretty much just that. Older computers ran with parallel ports that operated at 5V. Newer computers run with parallel ports that operate at 3 or 3.3V. Less power consumption. I'm not sure what information or links you are looking for, since this information would be in your computer's technical specs, or can likely be found on the manufacturer's web site. You should always check with your computer's hardware manual to determine the voltage of your ports lest you blow up your motherboard.

[Ak star]

Hi Baji,

I'm using the AT mode, I receive 5 volts on pin 2 on the parallel port when it is not at the origin and 0 volts at pin 2 when it is at the origin. Pin 2 is data bit 0 on the parallel port and i want to read the data bit 0 on labView. When i used my programme (without the index array) it was all high, but not the last led. With the index array it was all low. 

Message Edited by Ak star on 03-23-2009 09:00 AM

[Dennis_Knutson]

Your use of the index array function makes absolutely no sense. If you want a specific value from the boolean Array, use the index array function on that.

Message Edited by Dennis Knutson on 03-23-2009 08:15 AM

[Ak star]

Hi Dennis,

I implemented the index array the right way now and I improve the programme more. The result I obtain is that the first LED blinks when it receives/update the data (I think), however, this takes a longer time when it isn't at the origin. Also the second indicator blinks at the same time when it isn't at the origin and I think this is the indicator to show the 5V. I'm not sure if this is right and I was wondering if there's a better way (faster) or if i could show the actually voltage coming from the data bit 0.

Thanks

[smercurio_fc]

If you want to change the loop time while the loop is running then you have to place the "millisecond multiple" control inside the loop. Otherwise the loop will only ever see the value it was set to when it was first run. The first indicator, as you refer to it, is all the bit values of the port. The "second indicator" is a specific line, based on the value of the "index" control. If this is set to 0, then the "second indicator" will always show the value of bit 0. If this is set to 1 then the "Second Indicator" will always show thte value of bit 1.

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Ak star wrote:

The result I obtain is that the first LED blinks when it receives/update the data (I think), however, this takes a longer time when it isn't at the origin.

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Where the object is would make no difference on the rate of change of the LEDs. The rate of change of the LEDs is strictly controlled by your loop time, which is how fast you are reading the parallel port. 

[gaurav_sharma]

Hi dear,

 I am going to make RF robot using parallel port want to control mainly only two motors but i can able to understand that how In port.vi reads the parallel port mean in which pattern it reads the parallel port. Secondly, If it reads only data or the whole port i.e 25 pins.

 Please reply fast as my project is stucked.

Thanks in advance.

Regards

Gaurav Sharma

Message Edited by gaurav_sharma on 04-13-2009 10:52 AM

[Dennis_Knutson]

How much data you read will depend on what type of the In Port function you use. If you select the In Port8, you read 8 bits or 1 byte starting from the specified address. If you use the In Port16, you read 16 bits or 2 bytes. The In Port32 reads 32 bits or 4 bytes. Right click on the function and do a Select Type> to change.

Have you looked at the examples? Open the example finder and do a search for 'parallel'.

[gaurav_sharma]

Hi

 Actually I want to know that in that exmaple of "parallel port read and write loop.vi " that is present in LABVIEW I cant able to understand the cluster order of the parallel port present under IO Connector Status tab I know cluster order from 0-7 as this is so beacuse the data directly starts from pin 2 but I cant able to understand the rest of order of parallel port cluster present over there.

Secondly, cant able to understand how parallel port cluster changes its pattern for differnet port bytes i.e In port8, In port16, In port32.

Please explain it so that I cant understand.

Thanks in advance.

Regards

Gaurav Sharma

[Dennis_Knutson]

The function used in the example is the In Port32. This returns 32 bits of which only the first 24 have any meaning for the parallel port. The first 8 bits is the data register contents - 8 pins of the printer port. The next 8 is the status register - 5 pins of the printer port . The last 8 bits is the control register - 4 pins of the printer port. The physical order of the pins is obviously different than the logical order so the subVI 32bitread_to_dsub remaps them. It does that by using a cluster and ordering the controls in the cluster. So, pin1 in the cluster is actually element 16 in the cluster and pin 2 is element 0.

[gaurav_sharma]

As I am making PC controlled RF robot using parallel port in labview so in front panel I have provided five round led's(on - off) for front, back, right, stop and left movement. But I want to bind the key W, A, S, D for front, left, back and right movement respectively. So Please tell me how to bind this keys to round led's. As there is no alphabet key available under key navigation tab.

Or send any demo vi for better understanding.

Thanks in Advance.

Please reply fast.....

Regards

Gaurav Sharma

Message Edited by gaurav_sharma on 04-14-2009 12:52 PM