Download UDC 004.3`14 G.А. SIVYAKOVA (Karaganda State Industrial

UDC 004.3`14
G.А. SIVYAKOVA (Karaganda State Industrial University, Temirtau, Kazakhstan),
P.P. SAVIN (Karaganda State Industrial University, Temirtau, Kazakhstan)
А.P. CHERNIY (Kremenchuk Mykhailo Ostrohradskyi National University, Kremenchuk,
Ukraine)
ABOUT POSSIBILITY OF MODERNIZATION OF MOTHERBOARD
A20-OLINUXINO-MICRO
Abstract. In the course of research it has been tested motherboard of minicomputer A 20Olinuxino-Micro and identified opportunities to expand its functions. It was redesigned circuit
technology of board to install the module Wi-Fi and USB-hub. To build a USB-hub for 4 outputs it
was used integrated circuit GL850G from Genesys Logic, made in SSOP housing with a 28 planar
outputs. To implement the Wi-Fi module and Bluetooth, it was selected system in the AP6210
housing production AMPAK Technology Inc. Processing of board design, as well as the
development of modules USB-hub and Wi-Fi were made in computer-aided design DipTrace.
Further, the necessary production files for PCB design were prepared and sent to the manufacturer
CHENONN Electronic limited, China. After simulation, the manufacturer checks, equipment
components, visual inspection, testing board is ready for use without any additional firmware and
can be transferred into mass production.
Key Words: system-on-chip, A20-OLINUXINO-MICRO, USB-Hub, Wi-Fi module, DipTrace,
modernization.
Introduction. The system-on-chip is an integrated circuit (IC) that has integrated all
components of a computer or other electronic system. SoC may contain (processed) digital, analog,
mixed signal, and often radio function comprises - all of this fabricated on single substrate. Systemon-chip are widespread in mobile electronics, since they have a lower power consumption. Field of
typical application - embedded systems (embedded systems - is a computer system having
specialized functions within large mechanical or electronic systems, often with real-time
calculations [1-3]).
Technical characteristics of any device eventually lose their relevance, as well as production
capacity and need to be modernized with a view to subsequent use. Installation of new and
modernization of existing units can bring the device to a different level of features.
Purpose of the work. Modernization of the motherboard of minicomputer by using systemson-chip SoC.
Material and results of the research. System-on-chip - a ASIC is integrating on chip for
various functional blocks which form a finished product for use in autonomous electronic apparatus.
A typical embedded system that is based on SoC, usually contains the following interfaces and
controllers: a system bus and bus controllers LPC/ISA, PCI, PCMCIA; management controllers
NOR/NAND Flash, SDRAM, SRAM, DDR; controller Ethernet; serial interfaces UART,
SPI/SSP/uWire, RS232, RS422/485, CAN; wireless interfaces WiFi/IEEE802.11, ZigBee,
Bluetooth, IrDA; interfaces Flash- memory cards SD/MMC, CompactFlash and MemoryStick;
controller STN/TFT/OLED; matrix keyboard controller; wireless data communication modules
GSM/GPRS, CDMA, 3G, 4G (LTE) and etc.; modules receiving signals of satellite navigation
systems GPS and Glonass; hardware support for floating-point calculations, encryption, DRM and
etc.; interfaces for audio and video signals [3].
Modern microelectronic technology provides the following options for the implementation of
SoC: as a custom ASIC; on the basis of highly integrated FPGA. [1]
Both alternatives implementations have their advantages and disadvantages. When
implementing SoC as a ASIC, there is use a traditional ASIC design flow by using hardware-based
hard - functional blocks (HF blocks), integrated in the ASIC structure and synthesized HF blocks,
which the manufacturer translates into the physical structure with their own libraries of functional
elements. Thus, it is possible to replace systems on board by systems-on-chip. Realization of SoC
as a specialized ASIC requires a significant financial cost. An alternative would be the
implementation of SoC based on highly integrated FPGA. Benefits of implementing the SoC based
on the FPGA: low costs for development and production experimental samples; the possibility of
multiple correction of the project; the use of well-proven serial products; easier process of testing
and debugging.
As the object of modernization it has been chosen the motherboard А20-OLinuXino-MICRO
company Olimex (fig.1), manufactured under license Creative Common by YSA 3.0, on which as a
board design and all project-related schemes and CAD-files are allowed to freely use and creation
of derivative products for personal use and for commercial purposes. [2]
Figure 1 - View of motherboard
Board Revision selected for upgrading, comes installed Android 4.2.2 operating system (Jelly
Bean) and a set of basic applications. The board uses a dual-core processor Allwinner-A20-CortexA7 (SoC) with a clock frequency 1 GHz per core and dual-core graphics processing unit (GPU)
Mali-400MP. RAM size - 1 GB. Volume ROM is 4GB.
From devices required for any work with the minicomputer should be allocated input devices
(mouse, keyboard, microphone, touch panel, or various combinations thereof as appropriate) and
output information (for example, a monitor / projector / screen with HDMI input) and SD-card with
pre-installed OS, if the board does not have the built-in NAND-memory or using Debian OS. [3]
Due to the small number of USB-ports embedded on the motherboard (2 USB and 1 mini-USB
OTG), the user is deprived of the possibility of simultaneous use of more than three peripherals. By
connecting, for example, a keyboard and a mouse with the USB-interface, the user can not use other
devices (printer, scanner, the FLASH-drives, a webcam, the USB-modem, joystick, the Bluetooth
adapter, and so on). With the introduction on board the USB-Hub, this opportunity is acquired. The
modern level of technological development of mobile wireless involves the using communication
tools (communication standards 3G, 4G, Wi-Fi, Bluetooth, NFC, IrDa and etc.). The complete
absence of this type of communication (wireless) imposes a limitation when using the considered
board of minicomputer and moves device into the category of stationary. Thus, based on the
existing shortcomings, the task was the modernization of the board to introduce the necessary
modules in the scheme and the implementation of the scheme in the physical performance.
For a constructing USB-hub for 4 outputs it has been used integrated circuit GL850G from
Genesys Logic, Inc. (Taipei, Taiwan), made in the casing SSOP with 28 planar outputs. IP is fully
compatible with the universal serial bus (the USB), when it is characterized by simplicity of design
board, small cost in the production (cost-effectiveness), low power consumption.
There is integrated in the IP two step-down voltage regulator 5V - 3,3V и 3,3V - 1,8V.
Installed switches (software) level of low consumption (for autonomous operation from a USB hub,
of higher hierarchy), and high power consumption (operating on auxiliary power supply). [3]
In GL850G 8-bit RISC machines is integrated, a microprocessor to control the operation of
ports. The software controls the operation of Inputs / Outputs, configures the PID and VID markers,
stores them in EEPROM.
Each outgoing port GL850G supports bi-color the LED (semiconductor light-emitting diode)
notification of its status (non- / normal operation). GL850G also supports two modes of supply port:
individual (for each port), and gang-mode (the same load of each port).[4]
In the scheme of USB-host, in addition to the basic IP GL850G, follows the scheme applied
components are used. To obtain a stable clock frequency a crystal resonator at 12 MHz, 16 pF
Abracon Corporation. IC U11 SY6280 used as a programmable current-limiting switch with low
loss rate, able to protect the power supply against current overload and short circuit. The IC
integrated thermal protection mode and discharging the output smoothing capacitor after turning off
the device. To smooth the ripple current there are applied multi-layer ceramic capacitors in generalpurpose frame size 0603, electrolytic capacitors 16V 100mkF produced in China. For the formation
of a predetermined values of voltage and signal level are used thick-film resistors of different
manufacturers made in the 0603 size package (resistors with 0,063Vt power dissipation). For the
protection of the module of USB-host from the short-circuit there are responsible resettable fuses F1
6V, 2А, Multicomp production (Taiwan). There are two semi-conductor elements - light emitting
diode LED2 (Gallium Arsenide Phosphide on Gallium Phosphide Yellow Light Emitting Diode) –
for indicating operation USB-ports formed in the casing 0603 and the p-channel field transistor
MOP-structure Q-4 SOT-23 package. For better noise immunity of the transmitted signal and the
protection of both the device and connected by static electricity, metal casing connectors have a
connection to the bus GND.
For implementation modules Wi-Fi and Bluetooth system has been selected in the casing
AP6210 production of AMPAK Technology Inc. This system is used in the construction of devices,
the tasks of which is a web-bruazing, VoIP (Voice over Internet Protocol, or IP-telephony), using a
Bluetooth headset and portable navigation applications.
Module AP6210 meets the standard requirements IEEE 802.11 b/g/n (IEEE 802.11 — set
communication standards for communication in a wireless local area network frequency band of
0.9, 2.4, 3.6 and 5 GHz), with data rates 72,2Mb/s for class of 802.11n, 54MB/s for specification
802.11g, 11MB/s for 802.11b. Integration of the module into the scheme provided by the interface
SDIO (Secure Digital Input/Output - standard support which can be used with the expansion slot
SD / MMS format corresponding to the periphery) for Wi-Fi and UART / PCM (pulse code
modulation – it used to digitize analog signals) for Bluetooth.
In the scheme of Wi-Fi module, in addition to the main system in the AP6210 case, there is
used the following chart-forming components: IC U28 NC7WZU04 - ultra-fast dual-inverter; quartz
resonator 26 MHz 18pF TXC production; Multilayer ceramic capacitors in a general purpose
package size 0603 and inductance coils - for smoothing the ripple current; thick-film resistors of
different manufacturers made in frame size 0603 and 0402 - for the formation of a predetermined
voltage and signal level; to maintain a stable level of the signal is used Wi-Fi antenna module
production Hitachi, made on flexible circuits technology.
Processing of PCB design, as well as the development of modules USB-hub and Wi-Fi were
made in CAD DipTrace (Figure 2), the main advantages of which are easy to learn, powerful
features and Russian interface, compared to such CAD as a Altium Designer, P-CAD, SprintLayout, Eagle.[5]
Figure 2 – Modul MicroSD in CAD DipTrace
Stages of modernization of minicomputer boards were as follows:
1) Convert the design documentation files (circuit design and board design) the Eagle format,
using the built-in software package DipTrace converter, in files are supported by DipTrace.
2) Check for matching circuitry and design converted files by source.
3) Creation of schematics files Wi-Fi modules and USB-hub. Create UGO and models
component packages that are not in the standard library.
4) Edit the converted file in the board design in the PCB Layout with the formation of free
sites, designed to location integrable modules. The selected site is optimized: the conductors of the
surface layer is transferred into the inner layers, existing components are grouped and well
tolerated, the extra circuit components are removed or replaced existing analogues (used unification
of components, replacement with cheaper analogues).
5) Verification of compliance transformed printed circuit board by source. There is checking
the integrity of networks, equipment components. Checking is carried out automatically, software
functions complex DipTrace.
6) On the basis of the form of free areas of printed circuit board there is made layout and trace
elements modules from previously obtained files of schematics.
7) Positioning of developed modules to the prepared areas of the board. Produced update the
old filling, correction of errors layout and trace.
8) Further, on the basis of the original documentation, elaborated by manufacturer of SoC,
placed modules are connected by connections with the necessary network of board. Trace of
connections made by hand, using all 4 layers board and through holes connecting the conductors on
different layers. Upon completion of the process of manual tracing there is updated fill.
9) Checking the printed circuit board for compliance with the revised schematics. Visual
analysis of the resulting of the board designs in 3D preview module PCB Layout (Figure 3), the
correction of the identified errors and shortcomings of the trace / pattern layout.
10) The final stage: the creation of emblems of the developers, preparation of the necessary
production design the printed circuit board files and sending them to the manufacturer CHENONN
Electronic limited, China (Block A,Shayuanpu industrial zoon, Minzhi, Longhua town, Bao’an
district, Shenzhen, Guangdong).
Selection of the manufacturer's was carried out on the basis claims to the technological level of
production and economic reasons.
Figure 3 – 3D-preview of the printed circuit board (estimated rear view at an angle)
Next on the manufactured and tested by the manufacturer printed circuit boards was carried out
installation of components. The first launch was carried out from consecutively connected supply
ammeter. If the data are fundamentally different from a standard big side (before starting the
measurements are made similar working / reference device, in this case A20-OLinuXino-MICRO),
the device under test is disconnected from the mains immediately, find and eliminate the causes of
the significant power consumption. Each adjustment launch took place from checking the major
components in the presence of heat.
If the ammeter comply with previously specified criteria, is metered supply voltages at key
points in the board (5V, 3.3V, 2.5V, 2.2V, 1.5V, 1.2V), then checked the signal at the output of
VGA (maximum signal strength must be greater than 0.5V).
Tested thus minicomputer board is disconnected from the power supply in the Micro-SD card
connector is de-energized board inserted card with the installed Linux operating system (Debian),
made a similar check. In the absence of critical errors SoC should detect boot data stored on the
card and launch the system.
The successful launch of the system is determined by the periodicity of the flashing LED
signal, increased power consumption, setting the supply voltage of the processor cores and itself
SoC (via changes of registers of integrated microchip management system of power supply
AXP209), the presence of power supply at the output of USB-ports, also appears on the video
output signal to VGA.
The last stage of commissioning tests is to connect the monitor to the board of the
minicomputer (VGA connector). Produces a visual check of the stability of the work, as well as
checking using specialized programs, check the operation of input-output ports, Wi-Fi.
Conclusions. In the course of research has been tested motherboard of the minicomputer A20Olinuxino-Micro, redesigned circuit technology for setting a host controller module, developed
schematic diagram the USB-hub and Wi-Fi module, selected components of the scheme. The results
of this work can be upgraded board of the minicomputer A20-OLinuXino-MICRO considered
ready-to-use device.[6,7]
Redesigned board A20-OLinuXino-MICRO can be transferred to the production for the release
of finished products.
REFERENCES
1. A20-OLinuXino-MICRO Open-source single-board Android/ Linux mini-computer user’s
manual Revision C, August 2013. - Designed by OLIMEX Ltd, 2013. – 40 p.
2. David J Greaves System on Chip Design and Modelling. Part 2. – University of Cambridge,
2011. – 130 p.
3. Michael J. Flynn and Wayne Luk Computer System Design: System-on-Chip. – Wiley, 2011. –
360 p.
4. http://www.alldatasheet.com
5. http://diptrace.com/rus/
6. www://kgiu.kz
7. Varzin, D. Modernization motherboard minicomputer with the use of systems-on-chip
(SоC)/ D. Varzin, S. Zachvataev, P. Savin, G. Sivyakova //Electromechanical and energy
systems, modelling and optimization methods. Proceedings of the 11th International
conference of students and young researchers in Kremenchug April 08-09, 2015. –
Kremenchug: КrNU, 2015. – PP. 273-274.