UART in nexys3 by VHDL

[devchandil]

I am trying to send an 8 bit data by UART to my terminal, the baudrate I have selected is 9600 and my clock frequency is 100Mhz. The output I am getting on my screen is all garbage. Any help would be very valuable

com.vhd

uart_tx.bit

uart_tx.ucf

uart_tx.vhd

uart_tx.xise

[hamster]

Hi,

I think I see your problem.... do you ever set INDEX back to zero?

It might be easier initially to send additional 1 bits after the data to simplify things.... e.g. 0,a,b,c,d,e,f,g,h,1 and then 22 '1's (where the letters are your data bitsfrom the switches), and just repeat that over and over. Just have INDEX counting from 0 to 31,

You can then enhance that only send when the key is pushed (e.g not rolling from 31 back to 0 unless KEY='1', and then speed it up by sending fewer extra bits, until you are running at full speed.

[hamster]

On second glance you are setting INDEX back to zero, just not where I expected in the "IF (TX_FLG='0' AND START = '1') THEN" block.