Specifications

53
LDAA #$0A ;LOAD LINE FEED ASCII
JSR TXBYTE ;TRANSMIT TO SCREEN
RTS ;RETURN
The TXBYTE subroutine checks the serial ports status register to await the clear flag
before sending the data stored in accumulator A through the serial port. It is essential to
await the clear flag before sending data to avoid data contentions.
; TRANSMIT A CHARACTER STORED IN ACCUMULATER A
TXBYTE BRCLR SC0SR1, #$80 ;WAIT FOR CLEAR FLAG
STAA SC0DRL ;SEND DATA THROUGH SERIAL PORT
RTS
;**************************************************************************