flag26838 Posted February 3, 2015 Report Share Posted February 3, 2015 forum,i can't make this example work: http://gadgetfactory.net/learn/2013/12/02/the-quickest-way-to-implement-pc-to-fpga-communication-using-a-papilio-fpga-board/ according to the author i should: "Just build the project, download the project to the FPGA, open a terminal program (I recommend “Putty”), connect to the higher number COM port on the Papilio with the following parameters:9600 baudNo parity1 stop bit Then press some keys to light some LEDs." but the only led that i see blinking, is the TX led on the papilio board (every time i press a key on the terminal emulator, the led blinks - confirming that one byte was transmitted on the line), but the 8 leds on the logicstart megawing don't lit up. So, while trying to debug it, i slightly changed the design: http://pastebin.ubuntu.com/10042389/ 1) i connected the data_strobe line to the dp signal of the 7seg and set an initial value of '1' (DP should be off)2) i flipped the tmp signal ( <= '0' - turning on the DP) insided the if-block when the oversampled_bits vector was checked against the starting bit3) i "enhanced" the starting bit check, adding the check for the stop bit too what i expected was for the DP to stay off until i sent the first char, but to my surprise the DP was immediately lit up (even if i didn't open the terminal emulator, so having nothing connected to the ttyUSB line - and i was sure the TX led on the papilio boatd was off all the time).At this point, as another experiment, i changed the check for the stop bit (from "111" to "000"), and again the DP lit up immediately - so, no matter what i checked there, that if-block is always executed. Any idea what i'm doing wrong here or how to debug it?rs232_rx.tar Quote Link to comment Share on other sites More sharing options...
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