December 08, 2020
Characteristic description of rom.
ROM is a solid-state semiconductor memory that can only read data stored in advance. Its characteristic is that once the data is stored, it cannot be changed or deleted. Usually used in electronic or computer systems that do not need to change data frequently, and the data will not disappear because the power is turned off.
The data stored in the ROM is generally written before loading into the complete machine, and can only be read out during the working process of the complete machine, rather than being rewritten quickly and easily like a random access memory. The data stored in the ROM is stable and will not change after the power is off; its structure is simpler and it is easier to read out, so it is often used to store various fixed programs and data.
Except for a few varieties of read-only memory (such as character generators) that can be used in general, the content of read-only memory required by different users is different. For ease of use and mass production, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM) and electrically erasable programmable read-only memory (EEPROM) have been further developed.
How to calculate rom address line and data line?
If there are n1 address lines,
n2 data lines,
Then calculate the n1 power of 2 and multiply it by n2,
You can get the number of storage units.
A piece of ROM has 10 address lines, 8 data output lines, ROM has a total of 8192 storage units;
A piece of ROM has 32768 memory cells and 8 data output lines, while the ROM has 12 address lines.