Programmable

Programmable describes systems or devices that can be configured or controlled by a set of instructions (a program) rather than by fixed hardware. The term indicates reconfigurability through software, firmware, or other input, enabling different behaviors without changing the physical components.

Usage spans computing, electronics, manufacturing, and consumer devices. Common examples include programmable calculators and thermometers, programmable logic controllers used in automation, and programmable devices such as microcontrollers, field-programmable gate arrays (FPGAs), and programmable memory (PROM, EPROM, EEPROM, or flash). These allow users to tailor operations, control sequences, or data processing to specific tasks.

Programmable hardware can be broadly categorized as software-driven or hardware-configured. Microcontrollers are embedded processors with programmable software; FPGAs and PLDs allow reconfiguring logic circuits; PROM-based memories store code that persists without power. Some devices are semi-programmable, offering adjustable parameters while preserving core hardware.

Historically, the idea of programmable devices predates digital computers. The Jacquard loom used punched cards to control weaving patterns, and the concept evolved through mechanical and electronic automata to electronic computers. In contemporary practice, programmability is a defining feature of many technologies, enabling customization, automation, and rapid innovation.

Limitations and considerations include security, reliability, and the need for appropriate interfaces and tooling. Programs can be updated but may introduce bugs or vulnerabilities. The term programmable remains a broad umbrella for any system whose behavior can be changed by software or configuration rather than fixed at manufacture.