"On 2014ces, which just ended not long ago, wearable devices undoubtedly became the protagonist of this year. According to statistics, in mobile fields such as wearable devices and the Internet of things, products based on ARM core accounted for more than half of the country. However, under this situation, it can be called the king of performance PC Server giant Intel has released an open-source hardware board for mobile areas such as wearable devices - Intel Galileo.
What will you make？-- Intel Galileo
The Intel Galileo evaluation board is based on the low-power quark processor of Intel x86 architecture, and is compatible with the existing ardunio development board in terms of software and hardware design. In addition, it has an exquisite appearance like a work of Art (refer to Intel Galileo unpacking, at least the author has not seen anything more exquisite in workmanship in similar products), and the tempting slogan "what will you make?", Impressive. From Intel's attitude towards the release of Galileo, it is not difficult to see its determination to enter the mobile field. However, can Intel take a share in the low-power mobile field where arm is everywhere? With such questions, let's learn about the Intel Galileo evaluation board.
Intel Galileo evaluation board
Intel Galileo evaluation board is a dark blue 6-layer PCB board with length and width of 10cm * 7cm. Four positioning holes are provided at the four corners of the board to fix the subsequent card box or expansion board.
Intel Galileo evaluation board
On board chip:
Intel quark SOC X1000 processor, 400MHz main frequency, based on 32-bit compatible Pentium instruction set architecture;
Meguiar 256MB DDR3 memory, 8MB SPI flash w25q64fvssig;
12 bit SAR ADC Ad7298bcpz, Maxon TTL / RS232 level conversion IC MAX3232；
Ti power management chip tps652510, DDR3 power regulator tps51200, 5V / 3V level conversion IC ts5a23159;
Cypress IO expansion IC cy8c9540a, Ethernet transceiver dp83848i;
Onboard interface:
10 / 100Mbps Ethernet interface, RTC onboard 3V battery interface
Mini PCIe interface complies with pcie2.0 specification and can support micro SD interface with maximum expansion of 32GB
1 USB2.0 host interface, 1 USB2.0 client interface
Two UART interfaces (1 audio port, 1 pin array)
1 JTAG interface, 1 8MB flash ISP interface, 5V DC power interface
1 reset button and 1 reboot button
Galileo is the first piece of ardunio compatible for hardware and software The quark X1000 SOC card based on Intel 32nm process designed by uno R3 is a single core and single thread processor. Based on Intel's powerful x86 architecture, the quark X1000 has 400MHz main frequency, 512KB on-chip SRAM and 16kb first-level cache. The whole chip area is 15mm * 15mm and fcpga 393pin package.
Quark X1000 internal block diagram
Different from the previously evaluated boards using ARM core, quark X1000 is essentially different from ARM processor, so they all have their own characteristics:
Architecture, the quark X1000 based on x86 architecture adopts CISC (complex instruction set), so the number of instruction sets is far more than that of arm architecture processor using RISC (reduced instruction set)
The number of complex instruction sets of X86 requires more execution function units, and the corresponding performance increases. However, the internal circuit of the chip is often more complex than the processor of arm architecture, needs to integrate more transistors, and the power consumption is relatively large
This is what people usually call "under the same frequency, the advantage of x86 architecture lies in performance, and the advantage of arm architecture lies in low power consumption", so they are like fish in water in different fields. However, with the continuous diversification of scientific and technological products, their applications are closer and closer. While infiltrating each other's fields and competing with each other, their technology is constantly improving, X86 continuously reduces power consumption while maintaining performance improvement, while arm continuously improves performance while maintaining low power consumption, which is also loved by people.
Quark X1000 Max TDP 2.2W
Back to the quark X1000, we can see the quark X1000 from the above figure Max TDP (heat dissipation design power consumption) is 2.2W. For 3.3V chip power supply, the maximum frequency is 400MHz, and the maximum current reaches 660ma. Although the power consumption is much lower than that of other x86 architecture processors, it is obviously unacceptable in mobile low-power areas such as wearable devices and the Internet of things. Compared with processors based on ARM core at the same main frequency (such as cortex-a5, The dynamic power consumption is only 0.12 MW / MHz), and the power consumption gap can not be made up by performance. Therefore, it is not difficult to see that the commercialization of quark X1000 still has a long way to go. However, it is worth affirming that the quark X1000 is only priced at $5, which allows many friends who like DIY to try it.
Reset and reboot
As the first step for Intel to enter the open source hardware ardunio ecosystem, the Intel Galileo evaluation board not only removes its own novel quark X1000 processor, but also improves the people's understanding of the ardunio development board in terms of configuration. Moreover, in the software system, it is not only simple to run compiled programs like the ardunio development board, Galileo runs a compact Linux system customized based on the yocto project, which is stored in 8MB SPI flash. Due to capacity, the full version of the system can only be stored in an external micro SD card to run (mentioned later).
For such special reasons, the Galileo evaluation board has a special feature:
Reset and reboot
The Galileo evaluation board has two mechanical buttons, reset and reboot, which literally mean reset and restart? It seems that many people will understand it as one meaning. But here are different functions.
As mentioned earlier, Galileo runs a simplified version of Linux. The so-called ardunio compatible software refers to the execution of ELF files compiled by ardunio ide in linnux system, which can be vividly compared to "running app in Android system". So the role of these two keys is well understood:
Reset: reset the running ardunio program
Reboot: restart quark X1000, that is, restart Linux system
From here, we can also realize that Galileo is not comparable to the ordinary ardunio development board. In my opinion, it is more like a single board computer.
USB HOST、USB CLIENT、UART
USB host / client is familiar to everyone. Here we focus on the USB host interface of Galileo. Through micro USB OTG cable and USB hub, you can expand the keyboard, mouse and other slave devices. More importantly, you can expand the display screen of USB interface. As Galileo without VGA, DVI, HDMI and other video output interfaces, USB host interface is particularly important at this time.
There is another interface that must be mentioned here - UART. Galileo is a "single board computer". Without a standard video output interface, in addition to relying on the USB host interface to output the display, the rest can only view the system startup through the output of UART.
USB HOST/CLIENT、UART
However, Galileo uses a 3.5mm audio interface as the UART port. What is the reason for this? I can't understand it! Even from the other side. After looking around the Internet, I didn't see the serial port line of this interface. However, I can only identify the wonderful idea of Intel. Fortunately, there are pins on the back of the audio interface. On the other hand, DIY is a serial port line. Pay attention to the pin connection.
Connection of serial port cable
Ardunio compatible interface
As a board that is compatible with ardunio software and hardware, will the ardunio shield extension interface of Galileo evaluation board be different?
Boss ardunio development board and Galileo evaluation board
In the figure, compared with Galileo, a boss's ardunio development board is obviously missing two IO ports, namely SCL and SDA signal line interfaces of I2C bus. The new version of ardunio uno R3 will not have this problem.
However, from the schematic diagram of Galileo, we can find that the signal line of ardunio shield expansion interface is not directly led out from quark X1000 SOC, but through cypress IO expansion IC Cy8c9540a and ADC Ad7298bcpz is realized mainly because the GPIO port of quark X1000 adopts the level of 3.3V and cannot be directly connected with the 5V level of ardunio shield expansion interface, otherwise the quark processor may be burned.
Support Mini PCI Express interface
The highlight of Intel Galileo is the mini PCI Express interface, which is an interface based on PCI-E bus. Through it, devices such as solid state disk and wireless network card can be expanded, which is also an important symbol different from arm or other boards.
mini-PCI EXPRESS
Through the understanding of the hardware circuit design of the Galileo evaluation board, I believe you have a new understanding. Galileo can not only exist as a replacement product of the ardunio development board, but also has more complex, stronger configuration and more functions than the ardunio development board. Relying on the powerful Linux system, it can be used as a new platform for secondary development, The following figure is the hardware block diagram of the entire Galileo evaluation board.
Hardware block diagram of Intel Galileo evaluation board
Galileo power on start
After understanding the basic hardware design scheme of Intel Galileo, the author will power on and start, connect the previous DIY UART line to the computer, open the serial port debugging tool, set the baud rate to 115200, and then plug in the 5V DC adapter.
Galileo power on start
Linux system startup is OK. Galileo startup includes UEFI (Unified extensible firmware interface, which is used to automatically load the operating system from the pre started operating environment to an operating system), grub boot (multi operating system startup manager), and loading the Linux operating system. Its operating environment is like a standard PC.
After the system is started, you can enter the root command to enter the Linux command operation interface. Before developing the ardunio software environment for the Galileo board, you need to prepare the following steps:
Download the ardunio ide tool version modified by Intel for the Galileo board for a specific operating system, and extract it to the root directory of drive C
Connect the USB client interface of the Galileo evaluation board to the computer through the micro USB cable, install the driver, and a COM port will be displayed after success
Open the ardunio ide design tool of Galileo Version (the latest version 1.5.3 at present) and it will flash back. Set the regional language of the computer to English, and then restart; Or start the ardunio ide design tool normally by using the third-party software locale emulator.
There is one step that must be paid attention to: when connecting the USB cable, ensure that the Galileo evaluation board is connected to the DC power supply first, which is repeatedly emphasized in Intel's use specification. This is because the DC-DC power chip tps652510 used by the Galileo board will generate very high current at the moment of startup. Directly inserting the USB cable may cause damage to the board or computer. After completing all steps, we can normally open the ardunio ide tool for code writing, program download and other operations.
Galileo version of Arduino IDE
Open the arduinio ide tool of Galieo version, and you will find that its interface is basically no different from the unmodified Arduino ide. The new text also contains the necessary processes for the execution of two arduinio programs, void setup and void loop.
Select the Intel Galileo board through tool - > board and the correct COM port through tool - > serial port. After the configuration is completed, you can download the routine through file - > examples.
Download routines through ardunio IDE
Thanks to ardunio's powerful ecosystem, there are many routines in examples, but many of them need to use ardunio shield expansion board to run. Since there is no suitable expansion board on hand, we can only take blink routine as an example to compile and download routines through the right arrow symbol upload.
Download completed blink routine
After downloading the blink routine, the Galileo evaluation board automatically runs the program. You can see that the LED in the figure above is lit. Galileo can also use the interface in Arduino shield for DIY. Moreover, relying on the ecosystem of software and hardware compatible with ardunio development board, we can also directly use the routines in ardunio's official website.
Learn about the extension interface using ardunio shield through the blinkwithoutdelay routine on the official website. DIY an LED with a resistance of about 200 ohms in series, connect it to pin8 and GND of ardunio shield expansion interface of Galileo evaluation board, and load blin
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