Comparison Between 8085 & 8086 System Bus

There are three types of BUS, consists of following parts

1. Address Bus
2. Data Bus
3. Control Bus

These three bus have their own importance and their own defined work, we will discuss those on some other article.

Here is the comparison of 8085 and 8086 bus system.

8085 System Bus

• The 8085 system bus has 16 bits of address but with address lines A0 to A15.
• It has 8 bits data bus multiplexed with the lower order address bus to form a common address and data lines AD0 to AD7.
• It fetches one instruction byte at a time.
• The 8085 system bus is slower than the 8086 system bus.
• The 8085 microprocessor has the capability of addressing 2^16 = 64K of memory with its 16-bit address bus.

8086 System Bus

• The 8086 system bus has 20 bits address bus with address lines A0 to A19
• It has 16 bits data bus multiplexed with the address lines A0 to A15 and four status signal lines multiplexed with the address line A16 to A19.
• It fetches up to 6 instructions byte at a time.
• The 8086 system is faster than the 8085
• The 8086 microprocessor is capable of addressing 2^20 = 1024K = 1 MB of memory with its 20-bit address bus.