What is the function of sid and sod in 8088 processor?

Answer 1

The Serial Input Data (SID) and Serial Output Data (SOD) pins on an Intel 8085 are single wire I/O connections usable with the RIM and SIM instructions. Use of these pins is up to the hardware designer, but they can be used for serial data communications. There is no bit cell timer, however, such as provided by the 8253 USART. You have to provide all of the timing protocol with code, or with some other interrupt train, such as on RST 7.5.

Answer 2

The 8086/8088 and later processors do not have SID (Serial Input Data) or SOD (Serial Output Data) pins. The 8085 does, and they can be manipulated with the RIM (Read Interrupt Mask) and SIM (Set Interrupt Mask) instructions. While they can be used to implement serial communication, they can also be used to implement simple one bit hardware control of various things.