Parallel Port 16bits data half-duplex

[Catalinp]

Can I configure the PC's parallel port for a 16bits halfduplex comunication?Where can I find a .VI doing that ?

[Zvezdana S.]

There is no VI that would allow you to do this.
Actually, the parallel port cannot have 16 lines for input or output. I believe there are 8 output lines and 5 input lines.
Zvezdana S.

[wha@atmel]

Hi Zvezdana & Catalinp,

in general you are right, the Printerport allows only 8Bit transfer (bidirectional is possible) - but you should not give up too fast. With a little help of simple circuitry like
74HC4094 (4 of them are needed) you can solve this problem. Have a look to Datasheet of 4094 and you will see, how to clock Data into this Chip and how to connect a second Chip in series.
If only the parallel port is available you should "serialize" the 16bits and shift them out into two of these 8-stage-shift-and-store-registers - like a typical SPI-Interface. The same has to be done for Input operation. The speed of this Interface will be not very fast because of this overhead of clocking-out and �in ; but it will work.
Hope this leads to some
new ideas about this issue.

Regards
Werner

[Catalinp]

Thank you Werner!
So there is an answer...I don't understand very much of your comment...but I'll try to read more on the subject. I think my problem is more simple (than your comment), I need to write to parallel port on more than 8 bits...and my ideea was to use the input bits-for output too. It's possible...is an answer&thanks again !

[wha@atmel]

Hi,

there are of course other possibilities if you need to output 16Bits. Find attached a piece of schematic - there are two 8bit Latches used. The io-board.vi uses the control-port-Pins of Printerport for clocking Data into these Latches or to make them transparent. In case you select out0x, the circuit D2 in schematic is meant, out1x ==> circuit D3. The 5 bits of schematic in input direction are used with InPort.vi. (third address of LPT-sub.vi).

still questions ???????????

Werner