Operating System Process Scheduling Queues
The objective of multiprogramming is to have some process running at all times, to maximize CPU utilization. To meet these objectives, the process scheduler selects a process from a queue for execution on the CPU. More ...
Change Raspberry Pi Default Configuration
If you are a US user of the Raspberry Pi, you will discover that when you type, the characters displayed do not match our keyboard. When you type [shift][#] instead you get the British pound symbol. This is because Raspbian (and NOOBS) defaults to UK keyboard settings. More ...
Processor Interrupts
An interrupt is a signal to the processor indicating an event has occurred that needs immediate attention. When an interrupt occurs, the processors normal path of execution is interrupted in order to run a routine to service the interrupt requester. More ...
Intoduction to Digital Electronics
The entire field of computer technology relies on transistors. This article describes how transistors are constructed and how modern MOSFETs are combined to make digital logic circuits. More ...
Digital Logic Levels and Transfer Characteristics
A digital system uses discrete logic levels, 0 and 1, while the real world is a continuous range such as a voltage from 0 to 5. To make design easier, engineers view the system in the abstract. More ...
ARM Cortex-A72 Registers
16 registers r0 - r15 are accessable in the ARM Cortex-A72 user mode. In addition part of the CPSR (Current Program Status Register) is accessable. That part is the APSR (Application Program Status Register) which contains conditional status bits. More ...
Using The I2C Bus
The I2C bus is used for communications between individual integrated circuits located on the same PCB. The I2C protocol supports multi-master, multi-slave communication, which means you can add a lot of functionality to your design. More ...
Computer Buses
A 16-bit bus can transfer 16 binary bits simultainiously. This requires 16 separate metal traces on a PC board. We also need traces for control signals. The whole group of traces is referred to as a bus. More ...
Digital Logic Semiconductor Families
logic family refers to the way the semiconductors are designed to create gates. The first highly popular logic family, available in 1964, was TTL (Transistor-Transistor Logic). More ...
Processor Affinity in Symmetric Multiprocessing
Processor Affinity refers to a process's tendency to continue running on the processor on which it is currently running. When a process executes on a CPU, that process's cache is populated with its most recently accessed data, if a process is moved to a different CPU, that second processor's cache must be populated with that data. More ...
Multicore Programming
A recent trend in system design is to place multiple computing cores on a single chip. Each core appears as a separate processor to the operating system. We call these multicore or multiprocessor systems. More ...
Oscilloscope Required for Serious Digital Electronics Work
The oscilloscope is an instrument that displays digital signals on a line graph with time on the horizontal axis and voltage on the vertical axis. It will be difficult to do digital logic design without the use of an oscilloscope. More ...
