Interrupt Request Lines (IRQs)
What happens when the CPU (Central Processor Unit) is busy doing something, like defragmenting the hard disk, and you press a key on the keyboard? An interrupt (IRQ) is a connection between a hardware device and the CPU. A hardware device uses it's assigned IRQ line to signal or interrupt the CPU when it needs attention. More ...
The AMD Athlon 64 X2 Processor
The Athlon 64 X2 is the first dual-core CPU manufactured by AMD.
It is essentially two Athlon 64 cores on one die joined together with additional control logic. The cores share one dual-channel memory controller. The benefit of dual-core processors is their ability to process more software threads at the same time. However, many programs are written with only one thread. More ...
Using the Microcontroller Timers
Timing is an essential function for generating signals with precisely determined duration, or for counting external events. For this reason, a timer subsystem is present in all microcontroller implementations. More ...
Binary Number Representation and Binary Math
Computers perform all of their amazing work with only two voltage levels, one representing binary 0, the other representing binary 1. This article describes how to perform binary addition and subtraction. More ...
CPU Process Memory Address Binding
For a program to run on a CPU it must be brought from files in long-term, non-volatile storage to main memory. Addresses in the source program must be mapped to addresses in main memory. More ...
Virtual Memory and Memory Paging
In the early days of computers, memory chips were small capacity, scarce, and expensive. Because of this a memory management scheme called paging was invented. More ...
Operating System Services
An operating system provides an environment for the execution of programs. It provides certain services to programs and to the users of those programs. These operating system services are provided for the convenience of the programmer, to make the programming task easier. More ...
Microcontroller Registers
Registers are special small memory locations where the microcontroller can write data to or read data from. Special function registers help point to main memory locations, indicate the result of a mathematical operation, hold parts of an instruction or indicate the status of some operation or hardware feature. Some registers are general purpose and may be used by the programmer at their own discretion. More ...
Pentium P5 Processor
The Pentium P5 processor was introduced in 1993 was the first superscalar processor. It featured two integer pipelines and a pipelined floating-point unit. This article describes other innovations introduced in the P5. 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 ...
The Microcontroller Memory Map
a microcontroller is a set of resources. Each resource is identified by one or more addresses in an address space. The memory map is a graphic representation of how the resources are associated with addresses. More ...
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 ...
