5. Memory
R/WM – The microprocessor can write into or read
from this memory; popularly known as RAM. This is
volatile memory
6. Memory
Static RAM (SRAM) – This memory is made up of flip-
flops;
It stores the bit as voltage.
Low density
High speed
Expensive
Consume more power
7. Memory
Dynamic RAM (DRAM) – This memory is made up
MOS transistors gates.
It stores the bit as charge.
High density
Low power consumption
Cheaper
Require refreshing as capacitor discharges.
8. Memory
ROM – The ROM is non-volatile memory; it retains
stored information even the power is turned off.
This memory is used for programs and data that need
not be affected.
9. Memory
Masked ROM – In this ROM a bit pattern is
permanently recorded by masking and metallization
process.
10. Memory
PROM – This memory has nichrome or polysilicon
wires arranged in a matrix; these wires can be
functionally viewed as diodes or fuses.
11. Memory
Flash memory - This is a variation of EEPROM that is
becoming popular.
The major difference between the flash memory and
flash memory is in erase procedure.
The EEPROM can be erased at a register level, but the
flash memory must be erased either in its entirety or at
the sector (block) level.
It can be programmed at least million times.
12. Memory
The R/W memory is made of registers and each
register has a group of flip-flops or field effect
transistors that store bits of information.
In memory chip, all register are arranged in a sequence
and identified by binary numbers called memory
address.
To communicate with the memory, MPU should be
able to
Select chip
Identify the register and
Read from or write into the register
