The X 86 Microprocessors: Architecture, Programming and Interfacing (8086 to Pentium) 2nd Edition by Pearson

11-22

THE

x86 MICROPROCESSORS

iii) Each of the transmitted bytes is framed and sent. In the receiver, the framed charac-

ter is received only if the start bit is sensed. This is done automatically by the 8251.

iv) After the mode word and command word are sent to the control/status register, this

register is ‘read’ to confirm if T × RDY is high (for transmission) and R × RDY

is high for reception. Only after this is ensured, the data for transmission is sent to

the data register (for transmission), and the received byte is read (in the receiver

program).

v) The characters to be sent are stored in a memory location named TRANS at the

transmitter. On reception, they are saved in a location named RECD at the receiver

side.

11.4 | Internal Reset ...