LOGSYS Development Environment of Embedded Systems Tamás Raikovich Béla Fehér Péter Laczkó Budapest University of Technology and Economics Department of Measurement and Information Systems

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó1 Contents General characteristics of embedded systems Using programmable devices LOGSYS development environment: –Configuration of programmable devices –Communication capabilities –Power supply and monitoring –User interface

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó2 Embedded systems Small size, limited power consumption Extensive connection with the environment → communication Special, various functionality Typically implemented with programmable devices: –Microprocessor, microcontroller –FPGA –Etc. Development of the prototype is (usually) expensive.

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó3 Using programmable devices On-board components: –Microprocessors, microcontrollers –CPLDs, FPGAs –Serial EEPROM and FLASH Programming interfaces: –Standard solutions: JTAG, SPI, I 2 C –Vendor specific solutions: Microchip PIC: ICD port Atmel AVR: DebugWire ARM: SWD (Serial Wire Debug) Custom JTAG

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó4 Using programmable devices Programming support: –JTAG: SVF: simple, can be generated in most development environments STAPL: more complicated, loops, procedures –SPI: Intel HEX –I 2 C: Intel HEX SVF (Serial Vector Format) files: –Simple text file format –Industry standard –Describes the operations on the JTAG chain –Example: reading the device ID code //Created using Xilinx iMPACT Software [ISE Foundation i] TRST OFF; ENDIR IDLE; ENDDR IDLE; STATE RESET IDLE; FREQUENCY 1E6 HZ; //Loading device with 'idcode' instruction. SIR 6 TDI (09) SMASK (3f) ; SDR 32 TDI ( ) SMASK (ffffffff) TDO (f ) MASK (0fffffff) ;

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó5 Manufacturer development tools Manufacturer development tools: –Focus on their own devices. –Offer only a limited communication support. –Power supply is usually left to external instruments. For that reason, the LOGSYS development environment has been created, which integrates the following features: –Configuration –Communication –Power supply

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó6 LOGSYS environment User application Target system Development cable USB port LOGSYS development port: - Configuration interface - Communication interface - Power supply

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó7 LOGSYS development cable Full support: –JTAG interface for configuring the target system –Clock and reset signals for operating the target system –Serial input and output signals for communication –5V short circuit protected power output with adjustable current limit (450mA, 700mA, 950mA) –Voltage and current measurement

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó8 LOGSYS development cable Supported communication modes: –UART / USRT –BitBang I/O –Master SPI –Master I 2 C (TWI, SMBus) Different target systems can use different voltages for communication → level shifters (Vref JTAG, Vref I/O). This enables the cable to be easily attached to many target systems.

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó9 LOGSYS development cable Specification: –JTAG: f TCK = 1 MHz –UART / USRT: 4800 – bit/s –BitBang I/O: f CLK = 1 – 1000 Hz –Master SPI: f CLK = 2 kHz – 8 MHz –Master I 2 C: f SCL = 1 – 400 kHz –Reference voltages: 1.65 – 5 V

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó10 User application Integrated development environment. Customizable user interface (docking windows).

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó11 User application Cable browser: –Displays the connected cables. –Displays the available functions. Power panel: –Power output control. –Output current limit control. –Measurement results: Output and refererence voltages Output current

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó12 User application - Configuration Native configuration interface: JTAG interface. The LOGSYS system uses the industry standard SVF files (Serial Vector Format). In case of Xilinx devices, BIT and JEDEC files are also directly supported. Easily handles JTAG chains with devices from different manufacturers.

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó13 User application - Configuration Handling JTAG chains with devices from different manufacturers: –Device 1: Atmel ATmega128 microcontroller (AVR Studio 4) –Device 2: Xilinx XC9536 CPLD (iMPACT) ATmega128 XC9536

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó14 User application - Configuration Handling composite JTAG chains: –Atmel AVR Studio 4: necessary data have to be entered manually. Devices before and after Instruction bits before and after

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó15 User application - Configuration Handling composite JTAG chains: –Xilinx iMPACT: necessary data is imported from BSDL files (Boundary Scan Description Language).

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó16 User application - Configuration The LOGSYS configuration tool has an internal device database to manage composite JTAG chains. The required data can be entered manually or can be imported from BSDL files: –Device instruction register length –Device identification code

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó17 User application - Configuration Thanks to the JTAG device database, the composite JTAG chains can be handled without any difficulties: –Query the devices in the JTAG chain –Select the device to configure –Select the configuration file –The application configures the selected device

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó18 User application - Communication Basically, the UART can be used to communicate with the embedded system: –Most target systems have UART –Application level communication Virtual serial port driver → UART of the development cable can be accessed from Windows applications.

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó19 User application - Communication A simple terminal interface is available in the application for UART/USRT communication: –Adjustable parameters: baud rate, start & stop bits, parity, etc. –File I/O operations In USRT mode the development cable drives the clock output and f CLK = baud rate.

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó20 User application - Communication BitBang I/O: special communication mode for simple tests and educational purposes. In this mode, the software: –Directly controls the clock –At every rising or falling clock edge: Can change the MOSI and the RESET lines Samples the MISO line

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó21 User application - Communication The interface provides rich controlling capabilities: –Clock: free run, step, adjustable frequency. –Data I/O: adjustable clock edge, different number systems, file I/O operations. –Timing-diagram: zoomable, scrollable.

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó22 External applications User interface for SPI and I 2 C is device dependent: –EEPROM, FLASH –I/O expanders –A/D, D/A –Etc. Standalone applications: –SPI: FLASH programmer simple terminal interface –I 2 C: EEPROM programmer simple terminal interface These applications will be integrated into the LOGSYS development environment.

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó23 External applications Cable server application for Xilinx iMPACT Accessing the configuration interface of the development cable from Xilinx iMPACT: –Start the cable server application –Configure the cable connection in iMPACT: remote cable –iMPACT can use the JTAG interface

23/11/2007LOGSYS - Raikovich, Fehér, Laczkó24 Summary General purpose configuration and development tool. Functions: –Configuration of target systems. –Communication and test capabilities. –Power supply and measurement. Supports the manufacturer development environments. Integrated, user-friendly interface.

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