READY pin function in 8284A Clock Generator chip

Question

Briefly describe the function of READY pin in 8284A clock chip in relation to synchronization with other I/O or memory.

Answer
The ready pin generates the Ready signal for the 8086/8088. Usage example can be seen in the following READ and WRITE cycle where the important process only started after READY pin is set.

8284 Clock Generator using an external source for its frequency

Question
Modify the following  8284A clock generator circuit if it will be using an external frequency from another source.

Answer

EFI - changed from earth to the OSC input from other 8284A (EFI=external frequency input)
F/C' - changed from earth to Vcc (5v) because now the chip is using F(requency) input instead of C(rystal) input
Both X1 & X2 - grounded

Illustrated here

Calculate CLK & PCK frequency of a 8284A clock generator

Question

Given in the following diagram is a simple 8284A clock generator circuit that uses a 15MHz crystal input. Calculate the corresponding CLK and PCLK frequency. 

8284A with 15Mhz crystal diagram

Answer

CLK = 33% crystal/EFI = 0.33 (15Mhz) = 5 Mhz
PCLK = 50% crystal/EFI = 0.5 (15Mhz) = 7.5Mhz

8284A Clock Generator Output (CLK,Ready,Reset) tutorial

Question
There are 3 output generated by 8284A clock generator that is connected into 8088 microprocessor. Explain its function.

Answer
The 8284A clock generator consist of a synchronous divide-by-three counter. It has several output including CLK,PCLK,OSC,Reset,Ready. Out of this 3 pins are connected to the 8088 microprocessor which is CLK,Reset and Ready.

CLK- This is the clock output used by the processor and other devices that directly using the processor local bus. CLK output is 33% duty cycle clock driver.
RESET- This signal is used to reset the 8086 microprocessor
READY-This signal used to indicate the readiness of the microprocessor. It will be cleared after the guaranteed hold time to the processor has been met.