Hi I am trying to interface USART to 8051. In command register of 82C51 what is the purpose of bit4 (SBRK).I am actually trying to interface a modem to USART.The USART chip I am using is MSM82C51A.
It's defined in the Datasheet:
www2.okisemi.com/.../Intro-6080.html
See p11, and the timing diagram on p17