Boolean indicator doesn't update after reading from FIFO

[Loop3r_III]

Hi folks, 

I build a simple VI that reads the value in line DIO0 of 9401 module and it works I see the boolean indicator blinking. 
My purpose is to transfer boolean values from FPGA to the host and I used FIFO. When I execute the VI the indicator output from FIFO.read doesn't blink. I don't know how to resolve this issue. 
I uploaded a screen with VI code. 

[JensG69]

Please also post the code of the host-VI.

Regards, Jens

[Loop3r_III]

Hi Jens,

I uploaded the host code

[JensG69]

I assume the FIFO To_fpga goes from host to the FPGA?

Do you write to that FIFO anywhere? Otherwise the FPGA will wait infinitely at that node before writing another element to the FIFO to your host.

Regards, Jens

[Loop3r_III]

I executed the host VI and I obtained the error -50400, I attached a screen with the explanation of the error. 

[JensG69 · Accepted solution]

As I already stated your FPGA code is stuck at the FIFO node "To_fpga", as long as you do not send data from the host to this FIFO. It will only put 1 sample inside the FIFO "From_fpga". Therefore your HostVI cannot read 100 samples as you request which results in an error.

I strongly recommend to redesign your FPGA-code.

Regards, Jens

[Loop3r_III]

I tried to figure out how to redesign FPGA code but I don't know from where to start. I am working to a thesis and I have to develop a operative code.

[Loop3r_III]

I redesigned the FPGA code and now the boolean indicator has a true value and does not blink. Is this because in the FIFO I stored only one value? 

[JensG69]

Can you explain what you want to achieve?

Your last code is meaningless since the FPGA will not have an HMI. It just pushed the state of the DI before the first loop starts from one loop to another as fast as possible...

Regards, Jens

[Loop3r_III]

I wanted that the boolean indicator output from read method blinks, and I solved putting DIO0 inside the while loop.