The Science Fiction World of Xueba

At this time, Xia Peisu, who had been silent all this time, said, "Mr. Pang, what you mean is that the future development direction of Xinghuan Technology is to develop a brand new Internet terminal, and rely on this terminal to support a brand new system and commands. Integrate the architecture system and form an ecological closed loop?"

Pang Xuelin nodded with a smile, and said, "That's right, that's what it means."

Xia Peisu frowned and said, "If that's the case, during that period of time, HiSilicon only has input and no output. How long can you last?"

Pang Xuelin smiled slightly and said: "This is not difficult. Huawei is going to enter the mobile communication operator business next. Many chips need to be purchased from abroad. HiSilicon can undertake some chips such as DSP chips, ASIC chips, FPGA chips, etc. Research and development work. In addition, in the consumer business field, we are also preparing to do flash memory and second-generation synchronous dynamic random access memory."

"Flash storage? Second generation synchronous dynamic random access memory?"

Xia Peisu and Ni Guangnan looked at each other in surprise.

Flash storage refers to flash memory.

In this day and age, neither technology is fully mature.

In 1984, Fujio Masuoka of Toshiba Corporation first proposed the concept of fast flash memory.

Unlike traditional computer memory, flash memory is characterized by non-volatility, and its recording speed is also very fast.

Intel was the first company in the world to produce flash memory and put it on the market.

In 1988, Intel Corporation introduced a 256K bit flash memory chip.

It's the size of a shoebox and is built into a tape recorder.

Later, this type of flash memory invented by Intel was collectively referred to as NOR flash memory. It combines EPROM (Erasable Programmable Read-Only Memory) and EEPROM (Electrically Erasable Programmable Read-Only Memory) technologies and has an SRAM interface.

EPROM means that the content in it can be erased by special means, and then rewritten.

Its basic unit circuit (storage cell) often uses a floating gate avalanche injection MOS circuit, referred to as FAMOS.

It is similar to the MOS circuit. Two high-concentration P-type regions are grown on the N-type substrate, and the source S and drain D are respectively drawn out through ohmic contacts.

There is a polysilicon gate floating in the insulating layer between the source and drain,

There is no direct electrical connection with the surroundings.

This kind of circuit uses whether the floating gate is charged to indicate the storage of 1 or 0. After the floating gate is charged (such as negative charge), a positive conductive channel is induced between the source and drain just below it, so that The MOS transistor is turned on, which means that 0 is stored.

If the floating gate is not charged, a conductive channel will not be formed, and the MOS transistor will not be turned on, that is, 1 will be stored.

The working principle of the EEPROM basic storage unit circuit is similar to that of EPROM. It regenerates a floating gate on top of the floating gate of the EPROM basic unit circuit. The former is called the first-stage floating gate, and the latter is called the second-stage floating gate. Empty grid.

An electrode can be drawn out to the second-stage floating gate, so that the second-stage floating gate is connected to a certain voltage VG.

If VG is a positive voltage, a tunnel effect is generated between the first floating gate and the drain, so that electrons are injected into the first floating gate, that is, programming and writing.

If VG is made a negative voltage, the electrons in the first-level floating gate are forced to dissipate, that is, to be erased. Can be rewritten after erasing.

The basic unit circuit of flash memory, similar to EEPROM, is also composed of double-layer floating gate MOS transistors.

But the first layer of gate dielectric is very thin, as a tunnel oxide layer.

The writing method is the same as that of EEPROM, and a positive voltage is applied to the second-level floating gate to make electrons enter the first-level floating gate.

The read method is the same as EPROM. The erasing method is to apply a positive voltage to the source and use the tunnel effect between the first stage floating gate and the source to attract the negative charges injected into the floating gate to the source.

Since the positive voltage is applied to the source for erasing, the sources of each unit are connected together. In this way, the flash memory cannot be erased by byte, but erased in whole or in blocks.

Compared to the first NOR flash memory.

The second type of flash memory is called NAND flash memory.

It was developed by Hitachi in 1989 and was considered an ideal replacement for NOR flash memory.

The write cycle of NAND flash memory is 90% shorter than that of NOR flash memory, and its save and delete processing speed is relatively fast.

The storage unit of NAND is only half of that of NOR, and NAND has better performance in a smaller storage space.

There is a big difference between NOR type and NAND type flash memory.

For example, NOR-type flash memory is more like memory, with independent address lines and data lines, but it is more expensive and has a smaller capacity.

The NAND type is more like a hard disk. The address line and data line are shared I/O lines. All information similar to a hard disk is transmitted through a hard disk line. Compared with NOR flash memory, the cost of NAND type is lower, and the capacity Much bigger.

Therefore, NOR-type flash memory is more suitable for frequent random read and write occasions. It is usually used to store program codes and run directly in flash memory. Mobile phones are big users of NOR-type flash memory, so the "memory" capacity of mobile phones is usually not large; NAND-type flash memory It is mainly used to store data, such as flash drives and digital memory cards, all of which use NAND flash memory.

Xia Peisu frowned and said: "Mr. Pang, in my impression, the market for flash memory is not big now, and the scope of application is also very narrow, and the technology is mainly in the hands of big manufacturers such as Samsung, Hitachi, and Intel. Can you make money by doing this?" ?”

Pang Xuelin laughed and said: "Academician Xia, don't worry, the flash memory market is probably much bigger than you imagined! Some things involve commercial secrets, and I can't disclose them to you for the time being, but I can guarantee that a single flash memory, It is enough for HiSilicon to eat a lot.

Xia Peisu and Ni Guangnan looked at each other, a little surprised at Pang Xuelin's confidence.

Pang Xuelin didn't care about the thoughts of these two bosses, he didn't worry about the flash memory issue at all.

Not to mention the mobile phone memory of later generations, the USB flash drive that will appear in four years is enough to support the development of HiSilicon Semiconductor.

In the course of the development of the world computer industry, storage devices have always been the key to the development of computers. The earliest computers did not have storage devices. They used cardboard, and then replaced them with tapes. Later, storage devices finally appeared. It is a floppy disk, the more common one is a 3.5-inch floppy disk, also known as a disk A, and then finally there is a CD, whether it is a CD or not, it has been the most common storage device for a long time.

However, the one-time use feature of the CD has also made everyone criticize it.

Finally, in 1998, the U disk appeared. Due to its large capacity, the U disk can be used repeatedly and plugged in and out at will, making it the most popular mobile storage device until the 1920s and 1930s. The world's most popular method of mobile data transfer.

The U disk originated from Netac Technology in China, and this achievement is also regarded as the only original invention patent achievement belonging to the Chinese in the field of computer storage in the past two decades.

However, Netac has the patent of "U disk", but not the patent of USB flash memory or USB memory.

Because of this, in the real world, although Netac can obtain tens of millions of revenue every year through patent lawsuits, it has not developed.

Until Pang Xuelin entered China Sun World, Netac still made money by fighting patent lawsuits and renting houses, which is a complete insult to a technology company.

So Pang Xuelin does not intend to leave the U disk patent to Netac in the future.

Just a few months ago, Pang Xuelin had filed an application for a USB patent in the United States through Scooper.

The USB interface is one of the most common interfaces for connecting peripheral devices to a host computer.

In addition to the USB interface, there are interfaces such as parallel bus.

However, the USB interface has a great advantage that makes it very popular in this field, that is, the equipment with this interface can be plug-and-play (plug-and-play is also called hot swapping sometimes) on a computer.

When the computer is turned on, the peripheral devices must be turned on first, and then the host computer should be turned on, but the order is reversed when the computer is turned off.

The reason why this boot sequence should be followed is that before the computer starts, the power of all peripheral devices must be turned on and ready, and then wait for the host to check these devices one by one and install the corresponding software.

Only in this way can the computer run normally, otherwise the peripheral device may not be available or the computer may not recognize the peripheral device.

The emergence of the USB interface has changed this situation. If a certain device has a USB interface, it can be plugged into the computer host at any time regardless of the state of the computer at this time. operation to safely remove the device from the computer. This undoubtedly provides great convenience for people's study and life.

Historically, USB technology was invented by Intel Chief System Technician Bart. Intel finally decided to open this technology for free, and cooperated with companies such as Microsoft and Compaq to determine it as a common standard interface for computers.

After Pang Xuelin applied for the USB patent, he decided to open it for free, and through the relationship of Don Valentine, he lobbied Compaq, Microsoft, Intel and other companies to accept this unified standard interface.

The current feedback is very good. If there is no accident, from next year, most of the personal computers produced by computer manufacturers will have USB ports.

With such a foreshadowing, if Pang Xuelin withdraws from the USB flash drive in the future, no company will be able to bypass his patents from a technical perspective.

At that time, in the field of memory chips, HiSilicon can fully rely on the success of the USB flash drive to obtain good returns and form a virtuous cycle between R\u0026D-production-sales.

Of course, Pang Xuelin would not say this to Xia Peisu and Ni Guangnanming now.

Seeing Pang Xuelin's confident expression, Xia Peisu opened his mouth, but finally said nothing.

In the field of research and development, Xia Peisu is confident that he will surpass the young man in front of him.

But in terms of doing business, Xia Peisu has no say in front of Pang Xuelin.

Don't you see that even the RM Daily has publicly declared that Pang Xuelin is the entrepreneur leader of the younger generation?

Pang Xuelin's various operations in the marketing process of Xinghuan CVD, even everyone like Xia Peisu who is devoted to the academic field has heard of it.

This shows the popularity of Pang Xuelin in the country.

At this time, Ni Guangnan said: "Mr. Pang, what do you mean by the second-generation synchronous dynamic random access memory?"

Synchronous dynamic random access memory refers to SDRAM.

This is Dynamic Random Access Memory (DRAM) with a synchronous interface.

Usually DRAM has an asynchronous interface, so that it can respond to changes in the control input at any time.

SDRAM, on the other hand, has a synchronous interface that waits for a clock signal before responding to control inputs, so that it can be synchronized with the computer's system bus. The clock is used to drive a finite state machine that pipelines incoming instructions.

This allows SDRAM to have a more complex mode of operation than asynchronous DRAM without a synchronous interface.

Pipelining means that the chip can accept a new instruction before the previous instruction has been processed. In a write pipeline, the write command can be executed immediately after another instruction finishes executing, without waiting for data to be written to the store queue. In a read pipeline, the required data arrives a fixed number of clocks after the read instruction is issued, and this waiting process can issue additional instructions. This delay is known as latency and is an important parameter when buying memory for your computer.

SDRAM is widely used in computers, from the initial SDRAM to the subsequent generation of DDR, then DDR2 and DDR3 entered the mass market, and DDR4 entered the consumer market in 2015.

What Pang Xuelin wants to do is DDR memory.

The official name of DDR memory is DDR SDRAM (Dual Date Rate SDRAM). As the name implies, it is double-rate SDRAM. From the name, it is known that it is an upgraded version of SDR SDRAM. DDR SDRAM transmits signals once on the rising edge and falling edge of the clock cycle. , so that its data transmission speed is twice that of SDR SDRAM, and it will not increase power consumption. As for addressing and control signals, they are the same as SDR SDRAM and are only transmitted on the rising edge, which is compatible with the memory controller at that time. Compromise with performance.

DDR SDRAM adopts 184pin DIMM slot, the fool-proof notch changed from two in SDR SDRAM to one, the common working voltage is 2.5V, the frequency of the first generation DDR memory is 200MHz, and then DDR-266 and DDR-333 were born slowly Compared with the mainstream DDR-400 of that era, those running at 500MHz, 600MHz, and 700MHz are considered overclocking bars. When DDR memory first came out, it only had a single channel. times, if two DDR-400 memory forms a dual channel, it can basically meet the Pentium 4 processor with FSB 800MHz, and the capacity is from 128MB to 1GB.

DDR memory has achieved a complete victory in the war against RDRAM, so quite a few motherboard manufacturers have chosen to launch chipsets that support DDR memory. There are also NVIDIA, VIA, SiS, ALI, ATI and other manufacturers, so there are quite a lot of CPUs that can use DDR memory, such as Pentium 3 and Celeron with Socket 370, Pentium 4, Pentium D, and Celeron 4 with Socket 478 and LGA 775 , Celeron D, as long as you want Core 2 Duo, you can actually plug it into some 865 motherboards to use DDR memory. For AMD, K7 with Socket A interface and K8 architecture products with Socket 939 and Socket 754 can all use DDR memory.

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