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Embedded Systems

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In a previous post we saw a simple CAN library to handle the CAN interfaces of STM32 board. However one basic issue that we had to solve is the frames buffering (especially when we receive the frames). This issue came up by the processing time that each frame needs and the limitation that the receive interrupt routine should be as fast as possible. For that reason, the following source code presents an incoming CAN Frames…

Dynamic resources allocation has become even more attractive as a research direction with commodity computing gaining momentum and bringing new requirements regarding elasticity and flexibility and with the growing importance of cloud computing.  The aim is to deliver high-performance computational while leveraging on other aspects, such as energy consumption. Admittedly, heterogeneity comes at the cost of greater design and management complexity. A promising approach to address the difficulties posed by this scenario is to exploit…

The Controller Area Network (CAN, also known as CAN Bus) is a vehicle bus standard designed to allow electronic control units and devices to communicate with each other in applications without a host computer. STM32F779-Eval board has 3 CAN interfaces, however only the two of them have their own clock (master). For that reason the following library provides some C methods to activate and use those CAN interfaces. Beware that each CAN interface requires its…

I have recently been playing with UART and DMA, although i’m still getting my head around it,. DMA allows you to transfer large amounts of data through the system without getting the processor core involved. Rather than the CPU laboriously reading a byte, the writing a byte from one buffer to another, you’d give the DMA controller a pointer to the start of a source buffer, a pointer to the start of the destination buffer,…

Are you in need of an additional memory larger than EEPROM? Although EEPROM is a very easy and effective way of storing data on the board, the built in EEPROM only offers only a few bytes of storage. When working with larger or more advanced projects we may need to store additional data so an external memory solution. For that reason, MicroSD card enables you to do this quickly and easily. The following library provides…

The 3020 CNC router is a popular Chinese machine for a good reason. For around 500EUR, you can have a simple CNC with a rigid all-aluminum frame, three decent stepper motors, and pretty good resolution. However, a major disadvantage of this CNC is the out-of-date electronic parts. The motor controller is using a parallel port which is not available in any new computer(PC). For that reason, it is recommended to upgrade the motor controller to…

This project is a memory allocation scheme that provides efficient dynamic memory allocation for small embedded systems lacking a Memory Management Unit (MMU). The proposed Simple Memory Management Scheme (SMM) maintains a balance between performance and efficiency, with the objective to increase the amount of usable memory in MMU-less embedded systems with a bounded and acceptable timing behavior. This implementation does not require a hardware MMU, and does requires a few or no manual changes…

In general, an operating system (OS) is responsible for managing the hardware resources of a computer and hosting applications that run on the computer. An RTOS performs these tasks, but is also specially designed to run applications with very precise timing and a high degree of reliability. This can be especially important in measurement and automation systems where downtime is costly or a program delay could cause a safety hazard. To be considered “real-time”, an…

Until now we are all familiar with the Internet of Things concept. Or we think so. At its very basic level, IoT refers to the connection of everyday objects to the Internet and one another, with the goal being to provide users with smarter, more efficient experiences. A lot of people, as well as companies (probably for marketing reasons), have confused the real meaning of IoT. Developing a device that could be controlled from a…

Shared Memory is an efficeint means of passing data between programs. One program will create a memory portion which other processes (if permitted) can access. A process creates a shared memory segment using shmget()|. The original owner of a shared memory segment can assign ownership to another user with shmctl(). It can also revoke this assignment. Other processes with proper permission can perform various control functions on the shared memory segment using shmctl(). Once created,…