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PreonVM
PreonVM is an implementation of the Java virtual machine developed by Virtenio. The PreonVM was initially developed to run on the Atmel AVR ATmega256, but has been ported to ARM Cortex-M3 systems. Therefore the VM can run on a microcontroller with 8 kB RAM and 256 kB ROM at a minimum. The PreonVM requires no additional operating system and runs directly on the microcontroller. Every class file of the application is transformed via a ClassLinker to strip all parts of class files that is not required. This makes it possible to reduce the class file size by about 80%, which is required for a small device. The ClassLinker builds a .vmm file which combines all application class files in a special format which can be read and executed by the PreonVM on the microcontroller. The VM supports all Java data types incl. long and double, threads, synchronization, Garbage collection with memory defragmentation, exceptions, system properties and IRQ/event system. The PreonVM comes with a libr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Java Virtual Machines
This article provides non-exhaustive lists of Java SE Java virtual machines (JVMs). It does not include every Java ME vendor. Note that Java EE runs on the standard Java SE JVM but that some vendors specialize in providing a modified JVM optimized for Java EE applications. Much Java development work takes place on Windows, Solaris, Linux, and FreeBSD, primarily with the Oracle JVMs. Note the further complication of different 32-bit/64-bit varieties. The primary reference Java VM implementation is HotSpot, produced by Oracle Corporation and many other big and medium-sized companies (e.g. IBM, Redhat, Microsoft, Azul, SAP). Free and open source implementations Active * Codename One – uses the open source ParparVM * Eclipse OpenJ9 – open-source from IBM J9, for AIX, Linux (x86, Power, and Z), macOS, Windows, MVS, OS/400, Pocket PC, z/OS. * GraalVM – is based on HotSpot/OpenJDK, it has a polyglot feature, to transparently mix and match supported languages. * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C (programming Language)
C (''pronounced like the letter c'') is a General-purpose language, general-purpose computer programming language. It was created in the 1970s by Dennis Ritchie, and remains very widely used and influential. By design, C's features cleanly reflect the capabilities of the targeted CPUs. It has found lasting use in operating systems, device drivers, protocol stacks, though decreasingly for application software. C is commonly used on computer architectures that range from the largest supercomputers to the smallest microcontrollers and embedded systems. A successor to the programming language B (programming language), B, C was originally developed at Bell Labs by Ritchie between 1972 and 1973 to construct utilities running on Unix. It was applied to re-implementing the kernel of the Unix operating system. During the 1980s, C gradually gained popularity. It has become one of the measuring programming language popularity, most widely used programming languages, with C compilers avail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java (programming Language)
Java is a high-level, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let programmers ''write once, run anywhere'' ( WORA), meaning that compiled Java code can run on all platforms that support Java without the need to recompile. Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of the underlying computer architecture. The syntax of Java is similar to C and C++, but has fewer low-level facilities than either of them. The Java runtime provides dynamic capabilities (such as reflection and runtime code modification) that are typically not available in traditional compiled languages. , Java was one of the most popular programming languages in use according to GitHub, particularly for client–server web applications, with a reported 9 million developers. Java was originally developed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ARM Cortex-M
The ARM Cortex-M is a group of 32-bit RISC ARM processor cores licensed by Arm Holdings. These cores are optimized for low-cost and energy-efficient integrated circuits, which have been embedded in tens of billions of consumer devices. Though they are most often the main component of microcontroller chips, sometimes they are embedded inside other types of chips too. The Cortex-M family consists of Cortex-M0, Cortex-M0+, Cortex-M1, Cortex-M3, Cortex-M4, Cortex-M7, Cortex-M23, Cortex-M33, Cortex-M35P, Cortex-M55. The Cortex-M4 / M7 / M33 / M35P / M55 cores have an FPU silicon option, and when included in the silicon these cores are sometimes known as "Cortex-Mx with FPU" or "Cortex-MxF", where 'x' is the core variant. Overview The ARM Cortex-M family are ARM microprocessor cores which are designed for use in microcontrollers, ASICs, ASSPs, FPGAs, and SoCs. Cortex-M cores are commonly used as dedicated microcontroller chips, but also are "hidden" inside of SoC chip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java Virtual Machine
A Java virtual machine (JVM) is a virtual machine that enables a computer to run Java programs as well as programs written in other languages that are also compiled to Java bytecode. The JVM is detailed by a specification that formally describes what is required in a JVM implementation. Having a specification ensures interoperability of Java programs across different implementations so that program authors using the Java Development Kit (JDK) need not worry about idiosyncrasies of the underlying hardware platform. The JVM reference implementation is developed by the OpenJDK project as open source code and includes a JIT compiler called HotSpot. The commercially supported Java releases available from Oracle are based on the OpenJDK runtime. Eclipse OpenJ9 is another open source JVM for OpenJDK. JVM specification The Java virtual machine is an abstract (virtual) computer defined by a specification. It is a part of java runtime environment. The garbage-collection algorithm u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proprietary Software
Proprietary software is software that is deemed within the free and open-source software to be non-free because its creator, publisher, or other rightsholder or rightsholder partner exercises a legal monopoly afforded by modern copyright and intellectual property law to exclude the recipient from freely sharing the software or modifying it, and—in some cases, as is the case with some patent-encumbered and EULA-bound software—from making use of the software on their own, thereby restricting his or her freedoms. It is often contrasted with open-source or free software. For this reason, it is also known as non-free software or closed-source software. Types Origin Until the late 1960s computers—large and expensive mainframe computers, machines in specially air-conditioned computer rooms—were usually leased to customers rather than sold. Service and all software available were usually supplied by manufacturers without separate charge until 1969. Computer vendors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmel AVR
AVR is a family of microcontrollers developed since 1996 by Atmel, acquired by Microchip Technology in 2016. These are modified Harvard architecture 8-bit Reduced instruction set computer, RISC single-chip microcontrollers. AVR was one of the first microcontroller families to use on-chip flash memory for program storage, as opposed to Programmable read-only memory, one-time programmable ROM, EPROM, or EEPROM used by other microcontrollers at the time. AVR microcontrollers find many applications as embedded systems. They are especially common in hobbyist and educational embedded applications, popularized by their inclusion in many of the Arduino line of open hardware development boards. History The AVR architecture was conceived by two students at the Norwegian Institute of Technology (NTH), Alf-Egil Bogen and Vegard Wollan.Archived aGhostarchiveand thWayback Machine Atmel says that the name AVR is not an acronym and does not stand for anything in particular. The creators of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serial Peripheral Interface
The Serial Peripheral Interface (SPI) is a synchronous serial communication interface specification used for short-distance communication, primarily in embedded systems. The interface was developed by Motorola in the mid-1980s and has become a ''de facto'' standard. Typical applications include Secure Digital cards and liquid crystal displays. SPI devices communicate in full duplex mode using a master-slave architecture usually with a single master (though some Atmel and Silabs devices support changing roles on the fly depending on an external (SS) pin). The master (controller) device originates the frame for reading and writing. Multiple slave-devices may be supported through selection with individual chip select (CS), sometimes called slave select (SS) lines. Sometimes SPI is called a ''four-wire'' serial bus, contrasting with three-, two-, and one-wire serial buses. The SPI may be accurately described as a synchronous serial interface, but it is different from the Sync ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USART
A universal synchronous and asynchronous receiver-transmitter (USART, programmable communications interface or PCI) is a type of a serial interface device that can be programmed to communicate asynchronously or synchronously. See universal asynchronous receiver-transmitter (UART) for a discussion of the asynchronous capabilities of these devices. Purpose and history The USART's synchronous capabilities were primarily intended to support synchronous protocols like IBM's synchronous transmit-receive (STR), binary synchronous communications (BSC), synchronous data link control (SDLC), and the ISO-standard high-level data link control (HDLC) synchronous link-layer protocols, which were used with synchronous voice-frequency modems. These protocols were designed to make the best use of bandwidth when modems were analog devices. In those times, the fastest asynchronous voice-band modem could achieve at most speeds of 300bit/s using frequency-shift keying (FSK) modulation, while synchronou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CAN Bus
A Controller Area Network (CAN bus) is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other's applications without a host computer. It is a message-based protocol, designed originally for multiplex electrical wiring within automobiles to save on copper, but it can also be used in many other contexts. For each device, the data in a frame is transmitted serially but in such a way that if more than one device transmits at the same time, the highest priority device can continue while the others back off. Frames are received by all devices, including by the transmitting device. History Development of the CAN bus started in 1983 at Robert Bosch GmbH. The protocol was officially released in 1986 at the Society of Automotive Engineers (SAE) conference in Detroit, Michigan. The first CAN controller chips were introduced by Intel in 1987, and shortly thereafter by Philips. Released in 1991, the Mercedes-Benz W140 was the first produc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulse-width Modulation
Pulse-width modulation (PWM), or pulse-duration modulation (PDM), is a method of reducing the average power delivered by an electrical signal, by effectively chopping it up into discrete parts. The average value of voltage (and current) fed to the load is controlled by turning the switch between supply and load on and off at a fast rate. The longer the switch is on compared to the off periods, the higher the total power supplied to the load. Along with maximum power point tracking (MPPT), it is one of the primary methods of reducing the output of solar panels to that which can be utilized by a battery. PWM is particularly suited for running inertial loads such as motors, which are not as easily affected by this discrete switching, because their inertia causes them to react slowly. The PWM switching frequency has to be high enough not to affect the load, which is to say that the resultant waveform perceived by the load must be as smooth as possible. The rate (or frequency) a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interrupt Request (PC Architecture)
In a computer, an interrupt request (or IRQ) is a hardware signal sent to the processor that temporarily stops a running program and allows a special program, an interrupt handler, to run instead. Hardware interrupts are used to handle events such as receiving data from a modem or network card, key presses, or mouse movements. Interrupt lines are often identified by an index with the format of ''IRQ'' followed by a number. For example, on the Intel 8259 family of programmable interrupt controllers (PICs) there are eight interrupt inputs commonly referred to as ''IRQ0'' through ''IRQ7''. In x86 based computer systems that use two of these PICs, the combined set of lines are referred to as ''IRQ0'' through ''IRQ15''. Technically these lines are named ''IR0'' through ''IR7'', and the lines on the ISA bus to which they were historically attached are named ''IRQ0'' through ''IRQ15'' (although historically as the number of hardware devices increased, the total possible number of in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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