Hi all. Here is my problem.
I have done an application with manipulates the parallel port in several functions. But there is one that is giving me lots of problems. One of the functions switches one bit in the data register (0x378 address) periodically to sound a key matrix, this switch is asociated to a timer (50 ms period). The function to manipulate the port only changes one bit, but sometimes all bits in the port (included tho correspondant to control register) resets to a logic 0. I wrote a function associated to another timer which restores the previous values in the registers, but it isn't a valid solution for the design requirements.
I force the application to load the load of the low level NI driver at the beginning of the application andI'm using the outp(address,data) function.
I don´t know if it would be possible to solve this issue by using the VISA library.
Thanks
