I am using AVRStudio v4.08 and I have problem with UART simulation. I've done simple code to send one byte by UART and if I observed PINE register during simulation there was not activity in time (TXD pin was set to high).
Code is following:
; 4MHz clock
sts UBRRH,r17 ; baud rate H-byte
sts UBRRL,r16 ; baud rate L-byte
sts UCSRB,r16 ; enable TX+RX
sts UCSRC,r16 ; 1stop + 8data