Peripherals are connected to the CPU through the data bus in a similar way as the memory. Writing in certain memory addresses can result in altering the peripheral behavior. Reading allows to use the information provided by the peripheral.
#Peripherals Interaction
- On-chip
- Implemented inside the same silicon chip as the CPU
- e.g. timers, pwm, ADC, Serial
- Off-chip
- Connected externally to the address/data buses
- e.g. Network interfaces, Graphics accelerators
#Examples
- GPIO controllers
- General Purpose Input and Output controllers are used to control the pins that are coming out of the microcontroller.
- Timers
- Timing is a crucial part of any embedded system, and timers are used to control the blinking rate of LEDs or to generate precise delays.
- Pulse Width Modulation (PWM) controllers
- PWM controllers are used to control the speed of motors, the brightness of LEDs, and the frequency of audio signals 1.
- Digital to Analog Converters (DAC)
- Used to convert digital signals to analog signals.
- Analog to Digital Converters (ADC)
- Used to convert analog signals to digital signals.
- Serial Communication Controllers
- These controllers are used to communicate with other devices using serial communication protocols such as UART, SPI, I2C, and
Ethernet.
- Direct Memory Access (DMA)
- DMA Controllers are used to transfer data between memory and peripherals without the intervention of the microprocessor 1.
Peripheral Component Interconnect (PCI) Bus