MEMORY -ROM-EXTERNAL MEMORY DEVICES-READ or WRITTING
Memory is a essential component of a micro-computer system, it store the binary instructions and data for the micro processor.There are various type of memory,which can be classified in two groups; prime memory and storage memory. .
Magnetic tape and or disk are best example for old days.now a days there are lot of new technologies are available. USB pen drive,memory card, sata hard disk.
The R/W memory is made of register.each register are made by flip-flops.these flip flops are called memory cells.the number of bits stored in a register is called memory words.memory devices are available in various word sizes. The user can use this memory to hold program and and store data . On the other hand , the ROM stores information permanently in the form of diodes,the group of diodes can be viewed as a register . in a memory chip , all register are arranged in a sequence and identified by binary numbers called memory addresses. To communicate with the memory , the MPU should be able to
1. select the chips
2.identify the register
3.read from or write into the register
The MPU uses it's address bus to send the the address bus to send the address of a memory register and uses the data bus and control lines to read from or write into that register .
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...Labels: Intel 8085 microprocessor