Errors in UART read

[BrunoLevy]

Sometimes on the ULX3S I get random characters from the UART.
To reproduce: start FIRMWARE/EXAMPLES/tty_OLED.c
(or use the left arrow in the "commander" GUI to start the shell)

[BrunoLevy]

Fixed using BB/IFS1P3BX combo as follows:
(but I'm not 100% sure of what I deed though...)

 wire RXD_btw;
 BB RXD_bb(
   .I(1'b0), 
   .O(RXD_btw), 
   .B(RXD), 
   .T(1'b1)
 );
 IFS1P3BX RXD_pin(
   .SCLK(clk),		    
   .D(RXD_btw),
   .Q(RXD_internal),
   .PD(1'b0)		    
 );

[Mecrisp]

jamesbowman/swapforth#45
jamesbowman/swapforth#49