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Vehicle Controllers and Communication
Published in Iqbal Husain, Electric and Hybrid Vehicles, 2021
There are five basic types of memory: RAM, ROM, EPROM, electrically erasable programmable ROM (EEPROM) and flash memory. A RAM has the capability to both read and write so that the stored information can be retrieved (read) and new information can be stored (write). This type of memory is typically of static type, which means that the memory contents are lost once the microcontroller is powered down. The ROM allows data to be read from, but do not allow writing into the memory. ROM is a non-volatile memory that retains its contents even after power is removed. ROM is used for storing the user code that does not change during execution of the software instructions. The EPROM devices allow the user to apply ultraviolet ray to erase the contents of the memory and reprogram it. EPROMs are generally used during the development stage when the user’s code often changes. The EEPROM is a type of ROM whose contents can be erased electrically and reprogrammed. Flash memory is the latest type of non-volatile memory similar to an EEPROM. Once programmed, the contents of the flash memory remain intact until an erase cycle is initiated through software, and the device has not been powered down. The contents of flash memory can be erased electrically.
Spin manipulations in magnetic nanostructures
Published in Guo-ping Zhang, Georg Lefkidis, Mitsuko Murakami, Wolfgang Hübner, Tomas F. George, Introduction to Ultrafast Phenomena from Femtosecond Magnetism to high-harmonic Generation, 2020
Guo-ping Zhang, Georg Lefkidis, Mitsuko Murakami, Wolfgang Hübner, Tomas F. George
A computer memory is any physical device capable of storing the binary information. There are two types of computer memory: volatile and non-volatile. A volatile memory requires electric power to maintain stored information. For example, an operating system of your computer uses random-access memory (RAM) to process your commands. Most RAM available in the market uses semiconductor technology, i.e., it is electric-current dependent and therefore inevitably volatile. Each bit of information in semiconductor RAM is stored in a memory cell which consists of a tiny capacitor and a transistor called MOSFET (metal-oxide-semiconductor field-effect transistor). Billions of such memory cells are mounted on an integrated circuit (IC) or so-called microchip. A typical speed of RAM in a personal computer is a few GHz, which means that it can read or write a few billion bytes per second. Roughly speaking, it is said that the number of transistors in an IC doubles about every two years, which is called Moore’s Law.a (There is of course a limit as to what extent in time this law is valid.)
Programmable-logic controllers and operation
Published in Raymond F. Gardner, Introduction to Plant Automation and Controls, 2020
Memory, such as read-only memory (ROM) and random-access memory (RAM), is used by microcomputers and PLCs to retain the states of functions and devices. ROM is retentive memory that is maintained during a power-off cycle, and RAM is volatile that requires power to be maintained. The memory can be classified as program-executive memory (ROM), system memory (RAM), I/O status memory (RAM), data memory (RAM), and user memory (RAM or EPROM). These types of memory are allocated to addresses within the PLC memory chips. The executive memory is programmed once by the manufacturer, and the memory executes the program and does the scans. The system memory is where the operating system is loaded and where temporary information is stored during program execution, including error codes. I/O memory is where the input-and-output-device states are stored and modified, including virtual devices. Data memory is where results of mathematics, timers, counters, accumulators, and process parameters are stored. The user memory is where the program is stored and where the program deposits and recovers data values occurring during the program scans. The user memory also includes storage of ASCII messages, subroutines, and program functions that may be called as part of the main program.
The impact of scaling on single event upset in 6T and 12T SRAMs from 130 to 22 nm CMOS technology
Published in Radiation Effects and Defects in Solids, 2018
N. S. Yusop, A. N. Nordin, M. Azim Khairi, N. F. Hasbullah
Static random access memory (SRAMs) cells are high-speed semiconductor memory that use flip-flop to store each bit. The circuit is said to be static as the stored data can be retained indefinitely if power is being supplied. Basic SRAM (Figure 1) consists of two PMOS and four NMOS transistors that build up a single memory cell, where each bit is stored. Millions of cells make an array of memory (1).
Node Voltage and KCL Model-Based Low Leakage Volatile and Non-Volatile 7T SRAM Cells
Published in IETE Journal of Research, 2022
C. S. Hemanth Kumar, B. S. Kariyappa
In recent days because of faster growth and more significance of portable handheld electronic devices, such as smart watches, cellphones, PDAs, etc., need energy-efficient hardware. Random Access Memory (RAM) Chips are used in every electronic device essential for daily life.