Ch 10: Hardware Interrupts and PIC 8259

Read the following passage carefully and fill in the blanks in order: "Serial port is also accessible via ________ ports. ________ is accessible via ports 3F8-3FF while ________ is accessible via ports 2F8-2FF. The first register at ________."

MOV DX, 0x3F8
IN AL, DX

Read the following passage about UART serial port architecture and registers, then fill in the blanks in order using the provided word bank: Word Bank: (I/O, COM1, COM2, Transmitter, buffer, bit 0, 3FA) "Serial port is also accessible via ________ ports. ________ is accessible via ports 3F8-3FF while ________ is accessible via ports 2F8-2FF. The first register at 3F8 (or 2F8 for the other port) is the ________ holding register if written to and the receiver ________ register if read from. Other registers of our interest include 3F9 whose ________ must be set to enable received data available interrupt and bit 1 must be set to enable transmitter holding register empty interrupt. Bit 0 of ________ is set if an interrupt is pending and its bits 1-3 identify the cause of the interrupt."

MOV DX, 0x3F9
IN AL, DX
OR AL, 0x01
OUT DX, AL