3 ms·
The 8086 has 40 external pins [1]. There are 20 address lines shared with 16 data lines, so it's a 16-bit computer that can address 1 megabyte. The remaining p
by kens 6y ago
The 8086 has 40 external pins [1]. There are 20 address lines shared with 16 data lines, so it's a 16-bit computer that can address 1 megabyte. The remaining pins are mostly assorted control signals. (Intel liked to keep the pin count pointlessly low, so the pins are multiplexed and have several uses.)
The external pins are switching at the 5 MHz clock speed, and there are four clock periods for one memory bus cycle. The address pins send out the address the first cycle, wait a cycle for memory to respond, and read or write the data the third cycle.
The CPU and the memory bus are working at the same clock speed. (Although somewhat decoupled because the 8086 had prefetching.) I think you're going the wrong direction with kHz I/O and delivery bursts.
I've simplified things a bit. The 8086 User's Manual [2] explains all the signals in great detail if you really want to know.
[1] I see that you carefully counted the 45 wires off the die. The power and two grounds each use two bond wires in parallel for more current. There are two wires to bias the substrate. So that's the "extra" 5 wires.
[2] http://www.bitsavers.org/components/intel/_dataBooks/1981_iAPX_86_88_Users_Manual.pdf http://www.bitsavers.org/components/intel/_dataBooks/1981_iA...
- supernova87a 6y agoThanks! I will have a read through that manual!