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Forum: FPGA, VHDL & Verilog Nexy's 3 Dada reception help


von (unknown) (Guest)


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Hi all,
I am now using the uart prot on Nexy's 3 board to receive 8 bit data in 
9600 baud rate from PC. My design will simply respond "#" when upper 
case vowel is typed in hyperterminal and respond "N" when others are 
typed. However, the result will only echo N whatever I typed. I assumed 
that it was the endian problem on receiver side. May I know that If the 
PC send 01010101 to the board, will the Nexy's 3 board automatically 
change it to 10101010 or remains the same? Anyway, I have tried both way 
but the result only echo N but not #. I have also check the clock 
frequency. It is 100MHz on board and 9600 baud from PC. Therefore I made 
a counter to count every 100M/9600 = 10416 clk cycle to read one bit. 
Could any one help me to get out this situation? Thanks.
Tom

von P. K. (pek)


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Tom Sun wrote:
> My design will simply respond "#" when upper case vowel is
> typed in hyperterminal and respond "N" when others are typed.

Why not just echo what you typed? This would make debugging much easier, 
as you possibly could see regularity in characters being altered...

von Anja (Guest)


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> but the result only echo N but not #
so the baud rate and the timing of the sending routine seems to be 
correct.

> Therefore I made
> a counter to count every 100M/9600 = 10416 clk cycle to read one bit.

Usually you would want to read all bits in the middle of the bit.
So you should read the start bit 5208 clk cycles after the falling edge.

best regards

Anja

von Lothar M. (Company: Titel) (lkmiller) (Moderator)


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@Tom Sun
Pls attach your code file(s). The problem may be buried there...

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