What is Flash memory

Flash memory is the core of storage for solid-state drives, USB drives, and memory cards. It can typically store hundreds of gigabytes of data in a space the size of a fingernail. It is an invention that is as renowned as the Nobel Prize. Flash memory storage relies on floating-gate MOSFETs. Before discussing floating-gate transistors, let’s briefly introduce MOSFETs, as floating-gate transistors are an improvement based on MOSFETs. The principle of MOSFETs is quite understandable. These three black areas are metal conductors, and the n-type semiconductors on both sides contain many free electrons. If we apply electricity to the n-type semiconductors, they can conduct, acting like a piece of wire. The p-type semiconductor in the middle has very few free electrons, so when we apply voltage to the base, it is cut off because the concentration of free electrons in the p-region is too low to form a conductive channel.

To make the MOSFET conduct, we can apply a voltage to its gate, attracting the electrons in the p-region towards the gate.
Because there is a layer of silicon dioxide between the gate and the p-region, which is insulating, free electrons cannot pass through under normal circumstances. So, when we apply voltage to the gate, the free electrons in the p-region gather near the insulating layer, forming a conductive channel, and thus it conducts.

Floating-gate mosfets

However, when we remove the gate voltage, the electrons gathered near the insulating layer disperse, and no conductive channel is formed. Since no current flows, the MOSFET is cut off at this time. This is the circuit symbol for a MOSFET. Simply put, when we apply a high voltage to its gate, it will conduct, and when we apply a low voltage, it will be cut off.

Floating-gate MOSFETs are very similar to MOSFETs, except for an additional bar in the middle, which represents the floating gate. Since they are both MOSFETs, their structures are similar. A floating-gate MOSFET has an additional conductive floating gate layer added to the oxide layer of a MOSFET, allowing it to store information. Let’s talk about how to write information first. If we apply a high voltage of 20 volts to the gate and 0 volts to the substrate, some of the free electrons in the channel will be attracted to the floating gate layer. Even if we then power off, the free electrons will still be stored in the floating gate layer because the floating gate layer is insulated by silicon dioxide layers above and below, and the free electrons simply cannot escape. This is how information is stored, with the charge stored being considered a logical zero.There is also a question about how electrons can pass through the tunnel oxide layer, which is also an insulating layer. This is actually due to the tunneling effect. For example, a silicon dioxide oxide layer is normally insulating, but if we apply a voltage large enough, greater than 10 million volts per centimeter, electrons can pass through this insulating layer. This is the tunneling effect. When we apply a 20V high voltage to the gate, due to the thinness of the tunnel layer and the high voltage per unit thickness it withstands, electrons from the p-region are attracted. It is important to note that at this time, do not apply voltage to the drain, or a sub-threshold conduction channel will form, and electrons will flow in this manner, which would hinder the occurrence of the tunneling effect.

When we apply a low voltage of 10 volts, electrons cannot pass through the insulating layer, just like a conventional MOSFET. Understanding the principle of flash memory writing makes it easy to understand its parameter principle. We just need to apply a high voltage of 20 volts to its substrate while applying 0V to the gate. At this time, the free electrons imprisoned in the floating gate layer will be attracted out, and the data will be erased. Erasing is writing a logical one. Storing one bit of information requires only one floating-gate MOSFET. To store 1GB of information, at least 8.5 billion floating-gate transistors are needed. How do we control so much information?

How does nand flash work​

You can see this is a flash memory block that can store 16 bits of information. The middle ones are floating-gate MOSFETs that store information. The top and bottom ones are conventional MOSFETs that play a controlling role here. The horizontal ones are its word lines, connecting the gates of these rows of MOSFETs. The vertical ones are its bit lines. Its writing minimum unit is a page. A page is a row. When we want to write, we first need to erase all the data in this entire block, which means releasing the electrons stored in the floating gate layer, and all storage units will become logical ones.

How do we write by page? For example, if we want to write the page “word1,” we need to apply 20 volts of high voltage to the radiation MOSFETs of this page, and other MOSFETs should not be given high voltage. In this way, only the data of this page with 20 volts of high voltage can possibly be written. If we want to store a charge and write 0, we write 0 to its corresponding bit line, so free electrons will be attracted to the floating gate layer, and this bit will be written as logical 0. If we want to write 1, it’s very simple because we need to erase before writing, and after erasing, the data is all 1. We just need to keep the data unchanged. For example, if we want to write 1 to this bit, we write a high voltage to its bit line, which will hinder the tunneling effect. So, free electrons will not be captured by the floating gate layer, and it will remain logical one unchanged. The minimum unit for writing data is a page of data, and the minimum unit for erasing data is to erase the entire block. We need to give all of them zero volts and then apply a high voltage of 20 volts to the substrate.

You might be curious why the minimum unit for erasing is an entire block of data. Look at its cross-section, and you will understand. All storage units of this flash memory share a substrate. Just by applying a high voltage of 20 volts to the substrate, the operation of erasing the entire block of data can be completed. The minimum writing unit is a page because the gates of the MOSFETs on this page are connected together. This block of data can store 16 bits of data. One page is 4 bits of data, and a real flash memory page has 65,536 storage units per block. There are 512 pages in the data, so a block of flash memory data can store more than 33 million data points. This is what we call 4MB of data. Even if we want to write one bit of data, we also have to erase these more than 33 million bits of data before we can write.A block of data is 4MB, and to make up 1GB, you would need 256 flash memory blocks. The packaging size of the chip is standardized. To package enough storage units within the chip, the storage units must be made small enough to fit more of them in. However, as they are downsized, many issues arise. For instance, the tunnel oxide layer also becomes thinner. Due to the process of erasing and writing, electrons need to pass through the oxide layer repeatedly. If this happens too many times, the tunnel oxide layer can become damaged and fail to block the electrons, leading to data not being well preserved.

What is 3d nand flash​

To address this issue, humans invented 3D NAND flash, which eliminates the need to increase the number of storage units by downsizing MOSFETs. This is a 4-layer flash that stands the conductive channels upright, with horizontal pages of data. This area represents a block of data, and the middle contains all its storage units. So far, 3D NAND flash memory has achieved a stack of 232 layers, with a storage density of about 15GB per square millimeter. By using 3D stacking, not only can the unit capacity be increased several times, but also, because of the three-dimensional technology, the size of the storage units does not need to be reduced. As a result, the number of write-erase cycles is increased by more than tenfold. This is my understanding of flash memory technology, and I hope it helps your comprehension.

Essentials for Beginners

The development board may look simple, but many people are discouraged at the step of how to use it. Today, I’m here to teach you how to solve the problems of getting started with single-board computers (SBCs), taking the Orange Pi Zero 3 as an example. How many steps are generally needed to use an Orange Pi? First, prepare a USB Type-C power cable, a charger with at least 5V 2A , a memory card with a capacity of at least 8GB, and a Micro HDMI cable to connect to a monitor or TV to display information from the development board. Some Demo Boards may have DP or mini HDMI interfaces, or standard HDMI interfaces, and you will need to purchase the corresponding cables to match your development board.

If your monitor doesn’t have a DP interface, you can opt for a DP-to-HDMI cable. However, as of now, there are still few Demo Boards without an HDMI interface. We also need to prepare a keyboard, and if you’re using a desktop like Windows, you’ll also need a mouse. If your Demo Board doesn’t have WiFi or Bluetooth, you’ll need to provide an Ethernet cable and access to the internet. Finally, you’ll need a working computer with a USB port. If your Demo Board has onboard eMMC, you won’t need to prepare a TF card. If your development board also has an M.2 SSD interface and you happen to want to use an SSD, you’ll also need to prepare an SSD.

After preparing all this hardware, the next step is to install the system. Installing a system on a development board is simpler than on a computer. First, find the official website of the development board and download the system you want to use onto your computer. Then you can proceed to install the system. There are several installation methods, which differ depending on which storage medium you want to install the system on, such as a memory card, eMMC, or SSD. Installing on a memory card is the simplest.

Here, pay attention to the protocols and sizes of the SSDs supported by the development board. There are two protocols: M.2 SATA SSD interfaces and NVMe SSD interfaces. In terms of size, they vary based on length with M.2 2230, 2242, and 2280 being the main sizes. You need to choose the SSD based on the protocols and slots provided by the development board.

Pay attention to the protocols and sizes of the SSDs supported by the development board. There are two protocols: M.2 SATA SSD interfaces and NVMe SSD interfaces. In terms of size, they vary based on length with M.2 2230, 2242, and 2280 being the main sizes. You need to choose the SSD based on the protocols and slots provided by the development board.

Flashing the system to the SSD is also done using the Ralink development tools, with the difference being the configuration file; just select PCI and the system installation is complete.

Once the hardware and software are ready, plug in the HDMI and power cables and wait for the system to boot. Note that some Demo Boards have a switch, which could be a selection switch or a push-button switch, so you should refer to the documentation for operation. Generally, the system will start automatically when powered, and if it doesn’t start automatically, check if the switch hasn’t been pressed.

Professional Player Essentials

Some commonly used tools in electronic design, which can also be considered essential, start with soldering. First is the soldering iron, which comes in temperature-controlled and adjustable temperature models. A temperature-controlled soldering iron is similar to this type where you plug it in and it directly reaches a fixed temperature.

The higher the wattage, the faster it heats up. An adjustable temperature soldering iron is similar to this type, generally adjustable between 200 to 500 degrees, because some chips have requirements for soldering temperature and cannot withstand high temperatures, so this adjustable temperature soldering iron has a broader range of applications. When using a soldering iron, you need a soldering iron stand, which comes in various types and can be chosen based on personal preference.

Soldering Iron

When using a soldering iron, you need to frequently clean the tip, which is where the soldering sponge comes in, similar to the one in the picture. Then there’s solder, which comes in leaded and lead-free varieties, with different tin content and wire gauges. I personally often use 63/37 tin with a 0.6mm diameter.

There’s also flux in the form of solder paste or rosin, solder paste is similar to the one in the picture. Rosin is similar to this type of desoldering pump. When soldering and needing to remove some solder, a desoldering pump is needed, which looks like the one in the picture. Then there’s the solder wick, which is this type of perforated board, but it’s basically disposable, and after soldering, it’s hard to clean and reuse.

Breadboard

A breadboard is a type of board where you can insert components and perform some debugging and testing.

Dupont Wire

Dupont wires are used to connect two endpoints of a test circuit, generally divided into male and female ends, with the female end being this type with holes and pins. Choose according to your needs, and the male end looks like this, which is also a commonly used small tool in testing circuits. You can insert Dupont wires or their corresponding sockets, and this is the socket corresponding to the pins.

Tinned Wire

Then there’s tinned wire, also known as enameled wire, which comes in different thicknesses and lengths, and is also commonly used in testing to connect two solder points.

Others

Tweezers are used as conductors for adding small precision components, and small surface-mount resistors and capacitors are commonly used. Flush cutters are used for trimming, similar to this type, generally for cutting the leads of some soft components. To strip the outer skin of wires, you need wire strippers, which are also commonly used.

A multimeter is also the most commonly used tool for measuring current, voltage, resistance, capacitance, and continuity, which can be said to be the most commonly used tool in electronic design.

Conclusion

Then there are some tools that are not commonly used at the beginning of electronic design, but can be added later when needed, such as hot air guns, needle-nose pliers, screwdrivers, some fixtures, heat shrink tubes, regulated power supplies, oscilloscopes, and logic analyzers. Basic electronic design may not need these for the time being.

This article introduces how to choose and use STM32. It is hoped that through the introduction in this article, beginners can understand the basic concepts and entry guide of STM32 for subsequent learning and application. If you don’t understand embedded systems, come to me. Thank you, everyone.

TLC vs QLC: A Quick Overview

TLC VS QLC, TLC and QLC are types of NAND flash memory. They store data in cells, with each cell holding multiple bits. The more bits in a cell, the more storage capacity, but can slow down performance and reduce durability.

• Triple-Level Cell holds 3 bits per cell, balancing capacity, price, and speed. It’s commonly used in SSDs and memory cards for general consumers.
• Quad-Level Cell stores 4 bits per cell, offering larger storage at a lower price. But, this increased capacity comes with some trade-offs in performance and longevity.

This write-up compares both, showing you which is best for your device—like an SSD, SD card, or laptop upgrade.

Key Differences Between TLC and QLC

TLC and QLC flash storage vary in many ways, from cost to capacity and speed.

Cost

TLC and QLC NAND flash have a notable cost difference. With QLC storing four bits per cell, it’s generally cheaper than TLC, which only holds three bits. This extra data capacity in QLC lets manufacturers reduce production costs, allowing more storage in the same space.
However, QLC’s lower cost often means reduced speed and durability. For those seeking affordable, high-capacity storage, like for media libraries, QLC can be a solid choice. But, for high-performance or long-lasting storage, QLC’s compromises may not be worth the savings.

TLC VS QLC Lifespan and Durability

With three bits per cell, TLC is more durable than QLC, which holds four. This extra bit in QLC causes cells to wear down faster under frequent use. TLC handles more write-and-erase cycles and performs well under heavy tasks like gaming or workstation applications. QLC, in contrast, is ideal for data that is mostly read and rarely changed.

TLC VS QLC Speed and Performance

TLC tends to outperform QLC in speed and performance. It’s faster because it uses three bits per cell, making data processing quicker with less voltage consumption. This is especially noticeable in tasks like video editing, gaming, and software development, where frequent data writing is required.
TLC’s faster write speeds enhance both efficiency and overall experience. On the other hand, QLC is slower and might not handle demanding tasks well, but it works fine for basic storage like photos or media files.

TLC VS QLC Storage Capacity

QLC drives are great for those who need large storage. With the ability to store four bits per cell, it achieves high density and offers massive storage capacities, often reaching 4TB or more, all at a lower price than comparable TLC drives. This makes QLC a strong contender for archiving and backup needs.

Other Differences to Keep in Mind

• Power Use: TLC consumes more power because it stores three bits per cell. For most users, the difference isn’t significant.
• Heat: TLC generally creates less heat because it handles more write cycles without issue. QLC, due to its denser cells, may struggle with heat over time.
• Endurance and Use: TLC is more durable and works better across various tasks. QLC is ideal for light tasks like storing large files or backups where frequent writes aren’t required.

Relationship Between NAND Flash Types and Memory Cards

The performance of SSDs, SD cards, and microSD cards depends largely on the NAND flash type. SLC, TLC, and QLC each have their unique effects.

MicroSD Cards

• TLC Flash: More durable and faster, making it ideal for tasks with frequent writes like 4K video recording and high-speed photography. It offers better performance and reliability.
• QLC Flash: More affordable but slower and less durable. Best for storage-heavy tasks like media backups or long-term storage, but not suitable for high-performance needs.

SSDs

• TLC Flash: Offers a balance between price and performance, with solid read/write speeds and better durability than QLC. Great for general computing, gaming, and applications.
• QLC Flash: Cheaper but slower and less durable. Best for more storage needs like data archiving or home servers, but not recommended for high-demand tasks.

SD Cards

• TLC SD Cards: Best for 4K video or high-resolution images, offering fast write speeds and good durability for professional use.
• QLC SD Cards: Suitable for basic storage needs, like casual photography or personal use, where speed and frequent writes aren’t crucial.

TLC vs QLC: A Quick Comparison

Best Use Cases for TLC

TLC is ideal for users who need a balance between performance and reliability. It handles fast data access and long-term durability well, making it great for demanding tasks.
For gamers, TLC’s fast read and write speeds ensure smooth gameplay and quick load times. Professionals working on video editing or 3D rendering will find TLC’s ability to manage frequent large data transfers helpful. Content creators can rely on TLC for large, high-resolution files.
While TLC is more expensive than QLC, its consistent performance and durability make it a good investment if you need reliable storage for heavy tasks.

Best Use Cases for QLC

QLC memory caters to users needing substantial storage on a budget. It provides plenty of room but sacrifices speed, making it less ideal for users with high-performance needs.
QLC shines in media storage, offering plenty of room for large files like videos and photos at a lower price. It’s perfect for backups or casual storage needs, where speed isn’t as critical. If you’re doing lighter tasks or just need storage for everyday files, QLC is a solid choice.

Performance Benchmarks

TLC drives typically offer write speeds of around 500–550 MB/s. These speeds make TLC suitable for gaming, video editing, and handling large files easily.
QLC drives are generally slower, with write speeds between 300 and 500 MB/s. While this is slower, it’s fine for everyday tasks like file storage or light editing. However, frequent large file writes could slow things down. For users prioritizing heavy writes or long-term reliability, TLC is better. But for those who need bulk storage on a budget, QLC still delivers.

Future of NAND Flash

As storage demands rise, the NAND flash industry is adapting quickly. QLC (Quad-Level Cell) is gaining traction, with improved speed, durability, and efficiency shaping its future in the consumer market.
One advancement is 3D NAND stacking. This technology increases storage capacity while improving efficiency and lifespan by stacking memory cells vertically. The stacked structure reduces wear on cells during read/write operations, helping extend the life of devices like SSDs and microSD cards.
3D NAND stacking enables QLC to offer larger capacities without compromising performance. Additionally, better wear leveling and error correction algorithms are helping close the gap between QLC and TLC (Triple-Level Cell), making QLC a solid choice for budget-conscious consumers.

Final Words

The right option depends on your needs.

• Choose TLC for reliable, long-lasting performance and faster speeds for tasks like gaming or video editing.
• QLC is a good budget option if you need a lot of storage. It’s slower and not as durable, but it’s enough for tasks like archiving or media storage.

SLC and TLC: An Introduction

SLC and TLC are both NAND flash memory types that store data in distinct ways. Each type stores data differently, which impacts their performance, lifespan, and price.

Single-Level Cell

SLC stores a single bit of data in each memory cell. This simple design leads to faster read and write speeds. It also offers greater durability because the cells experience less wear over time. SLC is commonly found in high-performance settings like enterprise SSDs, servers, and industrial equipment. However, its advanced capabilities come with a higher price tag.

Triple-Level Cell

TLC stores three bits per cell, making it an efficient way to increase storage without using more space. It’s found in smartphones, laptops, and many consumer SSDs. The tradeoff is slower speeds and lower durability compared to SLC. It’s frequently used in budget-friendly SSDs and memory cards, offering decent performance for the price. But its lifespan tends to be shorter with regular use. This write-up will simplify these differences so you can select the right card confidently.

Key Differences Between SLC and TLC

Deciding between Single-Level Cell and Triple-Level Cell NAND flash technology can impact your memory card’s performance. Each has benefits, depending on your priorities like cost, durability, speed, and performance.

Cost

SLC memory cards come at a premium. Each cell holds just one bit, maximizing speed and durability. Yet, this design requires complex manufacturing, pushing up the price.
TLC cards, by comparison, store three bits per cell, making them easier and cheaper to produce. This high data density also allows for more storage at an affordable price, perfect for everyday users.

Life Cycle / Durability

SLC memory cards stand out for durability. Each cell holds a single bit, allowing SLC cards to handle thousands of write cycles without a noticeable slowdown. They’re perfect for intense use cases like professional video work or high-end applications, requiring stability.TLC cards, but, don’t last as long. With 3 bits per cell, they wear out quickly, especially for intensive writing tasks, such as video recording. Though TLC works well for most general uses, it may not endure as well under constant heavy use.

Speed

SLC memory cards offer faster read and write speeds due to their simple minimal design. They enable swift data access, making them ideal for handling large files like 4K videos or high-resolution photos. TLC cards work well for general use but can lag with heavy writing demands. You might notice this during large file transfers for gaming, video editing, or high-speed photography.

Performance

Known for both speed and resilience, SLC cards excel in high-demand situations. They handle intensive work, from video recording to large file storage, giving professionals reliable performance.

TLC cards are better for general use, such as saving photos, music, or videos on a phone or camera. However, they may not hold up well under demanding tasks like continuous 4K recording.

Power Consumption

SLC cards demand more power to support their high speeds and durability. This extra power use can affect battery life in devices like drones or cameras.TLC cards are more energy-friendly, needing fewer write cycles and lower power. They fit well in portable devices where conserving battery life is important.

Capacity

With smaller capacities, storing one bit per cell, SLC cards often come in lower storage sizes. It makes them suitable for users who prioritize durability over space.TLC cards can hold more data due to their three-bits-per-cell design, making them a good choice for extra storage without spending too much.

Impact of SLC and TLC on Memory Card Performance

Speed and Performance

Speed and performance in memory cards depend largely on the flash technology used. Here’s how they compare:

• Write/Read Speeds: SLC cards store just one bit of data per cell, making read and write processes faster. This gives SLC cards a performance edge over TLC cards, which manage more data per cell. For users, this means faster data transfer—key for time-sensitive tasks.

• Random Access Times: SLC cards excel at quickly accessing scattered data. This efficiency is crucial for tasks involving large files, where quick retrieval is essential. Whether you’re editing video or shooting in burst mode, SLC ensures smooth performance with minimal delay.
• Applications: SLC’s speed makes it perfect for demanding tasks:

1. 4K Video Recording: Recording 4K video requires high write speeds to avoid frame drops. SLC cards keep up without interruptions.
2. Large File Transfers: When transferring heavy files like RAW images or high-res video, SLC cards make it quick, saving valuable time for professionals.

Capacity

TLC provides substantial storage at a price SLC can’t match. Here’s why:

• Bits Per Cell:TLC cards use cells that store three bits, while SLC cards store only one bit per cell. This structure gives TLC cards a much higher data capacity than SLC cards of the same dimensions.
• Cost Savings:With higher data density per cell, TLC card production costs less, which can mean savings. If storage capacity matters more than speed, TLC cards provide a budget-friendly option. A 128GB TLC card often costs less than a smaller SLC card, making it great for affordable storage or backups.

SLC Vs TLC: Which is Better?

For Casual Users: TLC

For casual use, Triple-Level Cell memory is practical and cost-effective for:

• Photography & Video: Affordable with enough speed for HD videos and personal photos.
• Gaming: Suitable for mobile and console gaming, offering decent speed and storage at a low cost.
• Basic Storage: Plenty of space for files, documents, and images, perfect for non-demanding uses.

Benefits

• Large storage capacities at a lower cost.
• Suited for casual gaming, photos, and HD video storage.

Limitations

• Fewer write cycles mean reduced lifespan.
• Limited speed for professional tasks.

For Professionals: SLC

Single-Level Cell memory is well-suited for professionals requiring reliability and high-speed performance. It thrives under heavy read/write demands, especially in areas like:

• Video Production in 4K or 8K:SLC prevents frame drops, maintaining a steady recording speed for high-quality footage.
• Rapid-Fire Photography:With its quick speeds, SLC is best for photographers handling large RAW files, minimizing transfer delays.
• Data-Heavy Fields:SLC’s durability ensures consistent performance in applications needing frequent data writes, like research and data logging.

Benefits

• Exceptional durability and reliability.
• Maintains fast speeds for high-demand tasks.

Drawbacks

• Costs more per gigabyte.
• Offers less storage than TLC for a similar price.

Cost vs Performance

Picking between SLC and TLC is really a question of performance needs vs budget constraints.

When SLC Shines?

In fields needing speed and reliability, like videography, lab research, or high-speed photography, SLC’s performance and longevity are worth the extra expense. It’s an investment that supports intensive workflows.

Where TLC Fits Best?

For most people, TLC is a great fit. If you’re not working in a high-demand field, it provides solid value, offering ample storage for casual photos, videos, and everyday files.

The Future of NAND Flash Technology

Advancements in SLC and TLC

NAND flash technology is evolving quickly. SLC and TLC are improving as demand for faster, more durable memory cards rises.

SLC will continue to dominate in high-performance areas, like 4K video and professional photography. The focus will be on boosting endurance and speed while keeping costs down.

TLC will focus on maximizing storage and lowering prices. Its higher density makes it a good choice for everyday use, with manufacturers working on improving its reliability.

Emerging Technologies: QLC and PLC

Newer technologies like QLC and PLC are in development. QLC stores four bits per cell, and PLC aims to store five. These technologies offer more storage for less money but come with trade-offs in speed and durability. As they mature, they could change the memory card market, especially for budget-conscious consumers.

Trends and Predictions

In the future, mobile devices, cameras, and consoles will continue to demand more storage and faster speeds. SLC will remain important for professionals, while high-density NAND like TLC, QLC, and PLC will become more common for general consumers. Manufacturers will need ways to balance performance and price, giving users more choices.

SLC vs. TLC: Final Verdict

SLC and TLC memory cards suit different needs. SLC is fast and durable, perfect for pros handling 4K video and large data tasks, though it’s pricier. With more storage and a lower price, TLC is a good pick for casual users storing photos and documents.

New NAND tech like QLC and PLC continues to expand storage choices, balancing cost and performance for various needs.