"With the development of the times, the momentum of the rise of the chip industry is no less than that of the rise of the Internet. More and more students are pouring into the tide of the semiconductor industry. More and more students take finding a job in the chip industry as their graduation goal. Although different chip companies have different needs for job seekers, FPGA may become your stepping stone.
In this issue, Jaya brings a development board suitable for students, FPGA Xiaobai, and the surpasser spartan-6 FPGA development board produced by punctual atom. As a student or a new student, if you want to enter the semiconductor industry, you need some skills. There will be some differences between the semiconductor industry and the traditional electronic industry. For example, the traditional electronics industry is relatively simple. Generally speaking, the role of engineer generally includes three categories: Software Engineer, hardware engineer and test engineer. If it is further subdivided, the software may include firmware development engineer, kernel kernel engineer, Linux upper engineer, etc., and the hardware may have layout engineer, System engineer, RF Engineer, etc. But for the chip industry, this structure will be much more complex. Generally, it may include analog IC Design Engineer, digital IC Design Engineer, layout engineer, hardware engineer, software engineer, test engineer, etc. Analog and digital design engineers are responsible for building the blueprint of the chip. The layout engineer will realize the drawings of the analog part, and the engineer who verifies the software and hardware will mainly complete the chip centered verification, prototype development, scheme design, etc. As one of the stepping stones to enter the chip industry, FPGA and Verilog related technologies are worth mastering.
Nowadays, the chip industry is booming. People with lofty ideals are working hard on this broad road. As students or those who want to enter the chip industry, do you also want to show your skills in the chip industry? what? You said you wouldn't? It doesn't matter. You can't learn. The development board in this issue is such a classic model for pure novices. Please tell us that the theme of this issue comes from the surpasser FPGA development board of punctual atom:
If you read the simple instructions above and don't know what to say, come on! Please continue to read. Jaya will use the simplest language to explain that children's shoes with a little electronic foundation can be understood!
First of all, you need to understand what makes FPGA. The so-called FPGA is field programmable gate array, that is, field programmable gate array. It is a semi customized digital integrated circuit. To put it simply, we use the NAND gate we have learned in the digital circuit discipline to build a circuit. It is well known that only with the NAND gate, we can realize any logic in theory. The difference between FPGA and FPGA is that the combination of NAND gates is described in a language. This language is called hardware description language, such as VHDL, Verilog and system Verilog, Then we convert our hardware description language into the actual implementation of hardware circuit through the synthesizer and send it to FPGA. In this way, the FPGA can run in the way we described. You may say that this process is the same as MCU programming! As a beginner, you can think so for the time being, because after all, you need to hand write code, convert the machine into a language that the device can understand, and then execute it for the machine. But Jaya will clearly tell you that there is an essential difference between MCU and FPGA. In the final analysis, the synthesis of FPGA is to convert your language into a circuit. As long as there is an electrical signal, it will run directly to the past according to logic. The compilation of MCU is to convert the code into machine code, and then the core executes it line by line. Therefore, the program of single chip microcomputer will have a timing relationship. Only when the previous line is executed, the next line will be executed. The FPGA will not be based on the time allowed relationship. All circuits are executed at the same time. When the input gives a signal, the output will give feedback immediately.
OK, after a simple knowledge of popular science FPGA, let's simply open a box. We won't look at the box. It's a normal thick paper case. We directly disassemble the internal devices for everyone to see!
Let's start with a family photo. The components in the kit include:
one Adapter for JTAG
two Two DuPont lines
three One Mini USB to USB typea USB cable
four 12V 1A power adapter
five A DB9 to DB9 serial port cable
six JTAG cable
seven FPC out of plane line of the screen.
eight 4.3-inch LCD display with touch
nine Outsider spartan-6 FPGA development board Ontology
ten Infrared remote controller
Let's take a look at the motherboard. To be honest, Jaya's subjective feeling is very good. The whole board looks very exquisite and the overall layout is compact, but it will not appear very scattered. Punctual atom, as a large manufacturer of design and development boards, has a solid foundation, which is good for the layout and placement of interfaces and devices. The protection of the board is also in place. There are two layers of acrylic at the top and bottom for protection. The acrylic on the top surface has been matched, so that the board can obtain due protection, but it will not be blocked by the interface. It can be said that it provides the strongest protection for the development board under the premise of normal use.
The back of the board is very clean. There is only one TF card slot and a speaker for playing sound. The acrylic base plate also friendly opens holes for the speaker to facilitate sound transmission. In addition to solder joints and fixed holes, the remaining part is the decoupling capacitor required by spartan-6 FPGA. The little partner may ask why the decoupling capacitor must be placed on the back. Obviously, there are many gaps around the spartan-6 FPGA on the front. If there are no materials on the front and back, wouldn't it look cleaner? In fact, there are several reasons why the decoupling capacitor is placed on the back. Generally speaking, the placement position of the decoupling capacitor is very particular. Generally, it should be placed close to the pin and close to the pin in order to obtain the best decoupling effect of the power pin. For example, the common QFN package, SOP package and LQFP package pins are on the outside. It would be good to put the decoupling capacitor next to the chip if it is easy to understand. However, for spartan-6 xc6slx16, the nearest point of the pin of this ft (g) 256 packaged BGA chip is on the back of the PCB. In addition, even if the proximity principle is not so strict, the wiring of BGA chip will not easily place the decoupling capacitor around the chip. The reason for this is that generally speaking, a layer of signal layer can pull out up to 3 turns of pins of BGA chip, and the power supply is generally closer to the inside. Therefore, it is also a thankless thing to pull the inner power signal across countless pins to the edge of the chip（ PS: the acrylic anti-skid pad on the bottom is pasted by Xiaobian himself. The desktop is a little slippery. The board always moves when inserting wires or other actions)
Next, let's look at the core device on the whole development board, that is, the spartan-6 FPGA chip of xinlinx located in the center of the board. As a veteran in 2010, spartan-6 can be said to have this strong vitality. Up to now, there are still many spartan-6 application scenarios. Spartan-6 is made of 45nm and has a supply cycle up to 2027. It can be said that with the rapid iteration of electronic products, the performance of the chip can't wait to double in half a year, spartan-6 is still strong. This can cast the classic impression of the chip. It is like 8051 in single chip microcomputer and STM32F103 in arm 32-bit single chip microcomputer. Although the years have passed and newer and stronger products have come out, it is still impossible to erase the classics.
Spartan-6 series actually has many chips. The differences between each chip are shown in the table below. It can be seen that spartan-6 series can be divided into two categories: one with T and the other without T. the difference of X is mainly whether it has a transceiver, but what is the transceiver? As a novice, as long as we know that with a transceiver, we can receive high-speed signals through transceiver, such as PCIe. In addition to the difference of this transceiver, the other difference is the number of FPGA resources. As shown in the figure below, logic cells are all the logic resources owned by FPGA. Spartan-6 FPGA uses a 6-input LUT. The so-called LUT is a look-up table. The implementation of logic and or non in FPGA is realized by using LUT and its truth table, which greatly simplifies the design difficulty of FPGA. Make the same area stuffed with more logical resources.
Spartan-6 series has many packages. The logic resources of the same model are the same. Different packages make the number of pins available different. Spartan-6 series FPGAs cover the size from 8x8mm BGA to 31x31mm BGA. Similarly, larger packages can expand more pins. User I / O also expands from 106 user IOS to 576 user IOS with the increase of packaging. Our punctual atom surpasser spartan-6 FPGA development board uses the package of xc6slx16 ftg256. The number of corresponding resource bits is 24051 logic cells.
Spartan-6 device is easy to understand. Let's come back and take a look at our development board. On the whole, the surpasser development board of punctual atom completely includes the functions that novices may use. Rich resource interfaces will bring convenience to our FPGA learning.
The main resources of spartan-6 development board of punctual atom transcendent include:
Main control chip: Xilinx spartan6 series xc6slx16, package: ftg256, rate grade: - 2
Crystal oscillator: 50MHz active crystal oscillator
Flash: w25q128 QSPI flash of Winbond company is adopted, with capacity of 128Mbit (16m bytes)
DDR3: nt5cb128m16cp-di, capacity: 2GBIT (256M bytes)
EEPROM chip: at24c64, capacity: 64kbit (8K bytes)
1 power indicator (blue)
4 status indicators (LED0 ~ LED3: red)
1 program download completion indicator (green)
1 ATK module interface, supporting punctual atomic Bluetooth / GPS / mpu6050 / RGB lamp module
1 standard rgb888 TFT-LCD interface
1 OLED / camera module interface
1 6-digit nixie tube
1 RS232 / RS485 selection interface
1 can selection interface
1 channel can interface
1 channel RS232 interface (female head)
1 channel RS485 interface
1-way USB UART interface
1 channel HDMI interface
1-way Gigabit Ethernet interface (RJ45)
1 active buzzer
1 infrared receiver
1 TF card interface (on the back of the board)
1 JTAG debugging download port, 10PIN interface
1 set of 5V / 3.3V power supply expansion ports, supporting external power supply and external input power supply
1 DC power input interface (input voltage range: dc6 ~ 16V)
1 RTC backup battery base with battery
1 RTC real-time digital clock with PCF8563 chip
1 Mic (recording input)
1 channel audio input interface
1 channel headphone output connector
1 small speaker (on the back of the board)
One reset button can be used as the reset signal for FPGA program execution
4 function keys
1 capacitive touch button
1 power switch to control the power supply of the whole development board
Two 20x2 expansion ports, 80 expansion IO ports in total, and each group includes one 3.3V and 5V power interface
It can be seen that the resources of the transcendent spartan-6 development board are really rich. With rich resources and peripheral interfaces, it is more convenient for us to carry out various experiments. For example, basic functions, such as keys and lighting that beginners must understand, such as eth PHY control, LCD screen drive, camera interface, driving 8-bit CMOS sensor to obtain images through DVP interface, have strong playability, basically cover the requirements for getting started with FPGA and Verilog, and the logic resources of xc6slx16 are also enough to support beginners to build a soft core. As an entry-level development board, it is really the best choice. Normal energy generally, the development board will burn the test program before leaving the site to make sure that the board is intact, and the overtaker development board of punctual atom is no exception. Then our door will directly power on, power on to see the status of the board, and check whether the board will have accidental damage during transportation (it will be tested when leaving the factory), If there is a problem with the board, it is probably the physical damage caused by careless express brother). By the way, let's take a look at the power consumption of the whole board. Generally speaking, the exit program will try to verify the verifiable parts as much as possible. Although the logic may not be used up and the maximum power consumption cannot be measured, why do you think the logic with light will have the maximum power consumption? Here is another concept. Logic is often used. At the moment of power on, all logic is configured. The configuration process is equivalent to opening pipes. If many pipes work at the same time, there will be a super large instantaneous power extraction. At this time, the power supply must resist. Jaya has encountered it before, The power supply is pulled out at the moment of power on, resulting in the failure of the board to start. However, the spartan-6 scale should not have this problem. In addition, the more logic you have, the faster the speed, and the greater the natural power consumption.
The overall power consumption is 3W, which can be said to meet Jaya's expectations. The horn on the back will have a little white noise. When you stick your ear to the acrylic on the back plate, you can vaguely hear the rustling sound. So Jaya looked at the schematic diagram of the relevant audio part and found that it was still familiar with the formula. The function of the audio part was realized through an external wm8960 codec, which was connected with the FPGA through the I2S interface to send and receive audio data. In addition, one I2C was used to configure the wm8960. Wm8960 is also a codec commonly used in MCU. Using the same materials on different platforms is really a feeling of seeing old friends again.
We have a basic understanding of the hardware structure. Let's use the board to realize some functions. First, we need to have a
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