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Subject Code : 3330705 Name Of Subject : Microprocessor and assembly language programming Name of Unit : Introduction to microprocessor Topic : Multiplexed address and data bus Name of Faculty : H.M.Avaiya & N.D.Dhameliya Name of Students: ( i ) Parekh Krishna (038)
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Subject Code : 3330705 Name Of Subject : Microprocessor and assembly language programming Name of Unit : Introduction to microprocessor Topic : Multiplexed address and data bus Name of Faculty : H.M.Avaiya & N.D.Dhameliya Name of Students: (i) Parekh Krishna(038) (ii) Shah Rutu(054) Parul Polytechnic Institute
The multiplexed address/data bus Ad7-AD0 is used to transfer data and address both. • In order to perform the read or write operation , the memory device requires to identify memory location which is specified by 16-bit address. • The higher-order address is available through A15-A8 address lines and lower-order address is available through AD7-AD0.
[ FIG : DE MULTIPLEXING OF MULTIPLEX ED ADDRESS DATA BUS.]
The lower-order address must be latched as it is required by the memory device and AD7-AD0lines must be made free to transfer data. • The ALE signal is used to demultiplex AD7-AD0 as shown in figure. • During initial period of instruction execution ALE goes high and multiplexed address/data bus AD7-AD0contains lower byte of the 16-bit address.
When ALE goes low, this lower – order address is latched into latch and is made available to the memory device. • It makes the multiplexed path free for data transfer.