What is memory in an embedded system, exactly? Memory in an embedded system is a physical storage embedded device used to store two data types. The embedded system retrieves data from memory, processes it, and outputs data saved in memory. The data held might be intermediate data generated during the execution.
The instructions or opcode executing the processor's function refer to the programme information. When the programme runs, the CPU retrieves and executes the instruction from memory.
Types of Memory based on Storage Medium
The memory may be volatile and non-volatile, depending on whether the data holds (Storage Medium).
As long as power is provided to the memory device, volatile memories will preserve the data. The memory contents will wipe when the power is switched off. It's where we keep the data and the programme instructions.
Random Access Memory (RAM)
RAM is the processor's short-term memory, which it uses to run all the apps. As a result, accessing the RAM is extremely quick. Without RAM, the embedded system will not be able to function. A simple analogy is used to show how RAM works.
It's a sort of RAM that stores each bit with latching circuitry, which is made up of flip-flops. As a result, there is no need to refresh the memory.
When compared to DRAM, Static Ram operates at a faster rate and uses less power. It also serves as cache memory. They're more with low-cost microcontrollers.
Each bit is stored in DRAM using capacitors and transistors. There is charging and recharging cycle for the capacitors. Periodic refreshing is required to maintain its content, which refers to "Dynamic RAM." It uses more energy, which results in more incredible heat. DRAM is packed more densely than SRAM.
When the power to the memory device switches off, the content retains in non-volatile memory. After restarting the machine, the saved data may be recovered using this memory. In most cases, the bootup settings are saved in non-volatile memory. They are slower than volatile memory, but they can store more data for a longer time.
Non-volatile memory is available in a variety of forms. Addressed and addressed non-volatile memories are the two types of non-volatile memory.
A PROM is a logic gate-based programmable memory. The programmer can save data in PROM. Once the information holds in the gadget, it cannot be programmed.
EPROM stands for Erasable Programmable Memory, and it is made up of floating gate transistors. The end-user can save, wipe, and reprogram the data. To wipe the contents of an EPROM, it must be removed from the computer. It deletes by exposing the data to a UV light source.
Electrical signals store and delete information. At one moment, large chunks of data may be deleted. It does, but, have a set lifespan for wiping and reprogramming data.
In embedded systems, flash memory is a non-volatile electronic memory. Toshiba developed it in 1980, using EPROM technology. The read operation on the data stored in the flash memory is faster than the writing process.
NAND and NOR flash memories are the two types of flash memory. They're made up of logic gates that are either NAND or NOR.
Write and read operations are conducted page-by-page in NAND Flash Memory (Implantable eMMC, UFS, SSD, SD card). Omit, the erasing procedure is done block by block. NAND memory, which is utilised in USB flash drives, is often smaller. SD cards, or Secure Digital Cards, are non-volatile flash memory cards. It features a large capacity as well as a fast access speed. As a result, it exists in a wide range of consumer gadgets, including cell phones and so on. They come in a variety of sizes to suit various applications.
The memory selection impacts the performance of the embedded system. Some of the aspects to consider while choosing memory for an embedded system have been highlighted in this article.
Factors to Consider
When choosing a memory in an embedded system, the time it takes to read or write data should be considered the most crucial factor. In general, speed will not be a significant concern for small embedded applications. Yet, read/write access times should be faster for medium and high-range applications.
Latency is the delay between starting a data request and receiving it. The data stored in the memory is requested when the processor instructions are executed. For rapid operation, the processor must retrieve the needed data. Less latency means a faster process.
If your programme requires less than 60 MB of memory, 64 MB is the best option. At the same time, the worst sensation we get with a digital device is running out of storage. As a result, it is critical to select the Longsys capacity required for the application.
The memory device should be suitable for the embedded system in size. The size of the memory in hand-held devices should be small. If it's a desktop computer, the size considers medium. When choosing memory, choosing the right size is essential.
Memory consumes electricity to read or write data. Power consumption will be higher at fast access speeds, resulting in more power dissipation. The embedded system's lifetime will be shortened as the temperature rises. As a result, designers should use memory in an embedded system with the lowest power usage.
The selection of appropriate memory in an embedded system is critical in developing an Longsys embedded system. The designers must select the most suitable memory for their system. Your embedded application's purpose reflects in the memory device you choose.
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