Книга: Introduction to Microprocessors and Microcontrollers
Memories
Memories
The function of a memory is to store information – almost the same as we said for the register. Generally, a register lives within the microprocessor and stores small quantities of data for immediate use and it can do useful little tricks like shift and rotate. A memory is designed for bulk storage of data but that is all it can do – no tricks this time.
Well, almost no tricks – some types can remember the data even when the power is switched off. The ability to remember data after the power is switched off is the dividing line between the two main types of memory. If it loses its data when the power is switched off, then we call the memory RAM or volatile memory. If it can hold on to the data without power, we call it ROM or non-volatile memory (volatile means ‘able to evaporate’). This is seen in Figure 6.13.
Figure 6.13 The two classes of memory
Оглавление книги
- A flip-flop or bistable
- A register
- Shift registers
- Rotate registers
- Memories
- RAM
- Accessing memory
- Two types of RAM
- Memory organization
- Three types of ROM
- Pin layout of an EPROM
- Pin layout of a SRAM
- Pin layout of a DRAM
- Some more memories that don’t fit into the general pattern
- Memory maps
- Quiz time 6