Author Topic: how doesthe status&control pins of parallel port work another than Printer usage  (Read 21956 times)


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how many functions in inpout32.dll..only input32 and output32 functions are there (or)
any other direct function to work with statsu pins and control pins.Here i cannot write the control pins function.Always it shows C0=1,even if changed the bit position values of control pins.Controlling data pins by decimal number is easy.How to read/write the control pins and reading of status pins..I can change only data pins not the control pins.As per the Printer concept the strobe pin(C0) will acts as invert position Suppose if we set to zero the resultant shows the value 1.After changing the bit position too the control pin (C0) remains unchanged(default value is 1).the status bit value is 127.How does these control and status pins works?? I could find only printer related concept of controla and status bits?? how could i use the status and control pins for the pCB board having 8 leds and 8 relays.
having SN74Ls244N,ULN2003AN fitted on can i relate the control,data and status usage combinely So that i can communicate the PCB through my C# application by PC.

Jan Axelson

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This FAQ explains the port bits:

Status port is base address + 1. Control port is base address + 2.

To use the control bits as inputs, first write C0,C1,C3=0; C2=1. (I'm not 100% sure this technique still works on modern ports.)

Then you will have 4 control inputs, 5 status inputs, and 8 data outputs.

To expand the I/0 capabilities further, you can use decoders, data selectors, and flip flops. My Parallel Port Complete book shows how.

« Last Edit: June 27, 2015, 09:41:40 am by Jan Axelson »