Autonomous peripheral operation

In computing autonomous peripheral operation is a hardware feature found in some modern microcontroller architectures, especially those tailored for low power consumption. Allowing embedded peripherals to work independently of the CPU and even interact with each other in certain pre-configurable ways off-loads event-driven communication into the peripherals to help improve the real-time performance due to lower latency and allows for potentially higher data throughput due to the added parallelism. In newer implementations, it continues to function in sleep modes, thereby allowing the CPU to remain dormant for longer periods of time in order to save energy. Conceptually, it can be seen as a generalization of and mixture between direct memory access (DMA) and hardware interrupts. Peripherals that issue event signals are called event generators or producers whereas target peripherals are called event users or consumers. In some implementations, peripherals can be configured to pre-process the incoming data and perform various peripheral-specific functions like comparing, windowing, filtering or averaging in hardware without having to pass the data through the CPU for processing.

Known implementations include:

• Event System (EVSYS) in Atmel AVR XMEGA 8-bit microcontrollers since 2008
• Peripheral Event System (PES) with SleepWalking in Atmel AVR32 AT32UC3L 32-bit microcontrollers since 2009
• Peripheral Reflex System (PRS) in Energy Micro/Silicon Labs EFM32 32-bit ARM-based microcontrollers since 2009
• Event Link Controller (ELC) in Renesas microcontrollers since 2011
• Programmable Peripheral Interconnect (PPI) in Nordic nRF 32-bit ARM-based microcontrollers since about 2011
• Event System (EVSYS) with SleepWalking in Atmel/Microchip SAMD, SAML and SAMC 32-bit ARM Cortex-M0+ microcontrollers since 2013
• Core Independent Peripherals (CIP) in Microchip PIC16F and PIC18F as well as Microchip AVR ATtiny 8-bit microcontrollers since 2015
• Peripherals Interconnect Matrix in STMicroelectronics' STM32 32-bit ARM-based microcontrollers since 2015

See also

• Channel I/O
• Peripheral DMA controller (PDC)
• Clock gating, autonomous peripheral clock gating
• Power gating
• CPU power dissipation
• Low-power electronics
• Event-driven architecture
• Event-driven programming

Further reading

• Kragnes, Espen; Eieland, Andreas. "Redefining the Power Benchmark" (PDF) (White Paper). Atmel. Archived from the original (PDF) on 2018-05-01. Retrieved 2018-05-01. {{cite web}}: Unknown parameter |dead-url= ignored (|url-status= suggested) (help)
• Silicon Laboratories. "Low Power Technology: Microcontroller Peripherals Push the Boundaries of Ultra-Low-Power". Retrieved 2018-05-01. {{cite web}}: |archive-date= requires |archive-url= (help); Unknown parameter |dead-url= ignored (|url-status= suggested) (help)
• Coulson, Dave (2011-10-12). "The Need for Autonomous Peripheral Interoperation in Sensorless BLDC Applications". Convergence Promotions LLC. Archived from the original on 2018-05-01. Retrieved 2018-05-01. {{cite web}}: Unknown parameter |dead-url= ignored (|url-status= suggested) (help)
• "A closer look at Atmel's Peripheral Event System". Archived from the original on 2018-05-01. Retrieved 2018-05-01. {{cite web}}: Unknown parameter |dead-url= ignored (|url-status= suggested) (help)
• "Peripherals interconnections on ST M32F405/7xx, STM32F415/7xx, STM32F42xxx, STM32F43xxx, STM32F446xx and STM32F469/479xx" (PDF) (Application note). STMicroelectronics. AN4640. Archived from the original (PDF) on 2018-05-01. Retrieved 2018-05-01. {{cite web}}: Unknown parameter |dead-url= ignored (|url-status= suggested) (help)