ISA (Industry Standard Architecture) was first used with the IBM PC in 1981. It was the first open system for PC architecture. No restriction was put on the use of this interconnection method by the IBM. IBM offered free licensing of this PC architecture technique which resulted in more popularity of this. Some main features of 8 bit ISA are:
1) It was introduced by IBM and was the first open system for PC architecture.
2) It provides data transfer rate up to 4.77 Mbps.
3) ISA interface contains 62 pins to interface add on cards. These 62 pins are arranged in two rows, each containing 31 pins.
4) Distance between each pin is 0.1 Inches.
5) 8 Bit ISA make use of Following signals:
3 Ground Signals
2 +5V DC Supply
+12,12,-5V DC supply
Bidirectional 8 bit data Bus.
20 Address line, hence memory address space of 1MB (220=1MB)
3 DMA request lines
3 DMA acknowledge lines.
Six Interrupt Support
2) It provides data transfer rate up to 4.77 Mbps.
3) ISA interface contains 62 pins to interface add on cards. These 62 pins are arranged in two rows, each containing 31 pins.
4) Distance between each pin is 0.1 Inches.
5) 8 Bit ISA make use of Following signals:
3 Ground Signals
2 +5V DC Supply
+12,12,-5V DC supply
Bidirectional 8 bit data Bus.
20 Address line, hence memory address space of 1MB (220=1MB)
3 DMA request lines
3 DMA acknowledge lines.
Six Interrupt Support
Table given below illustrates all signals used by this connector along with their functions:
