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Microprocessors and -controllers

Terminology

Microcontroller vs -processor

MCU

An MCU is a group of microcontroller units that share a common architecture, design, and often the same core features

  • ARM Cortex-M is a popular MCU family, where multiple manufacturers like STMicroelectronics, NXP, and Microchip produce MCUs that are based on the ARM Cortex-M core.
  • AVR is another MCU family, famously used in the Arduino platform.
  • PIC is a family of MCUs from Microchip Technology, with a range of devices from small 8-bit controllers to more powerful 16-bit and 32-bit versions.

Within each MCU family, you’ll typically see models that differ by features like:

    Flash memory size RAM size Clock speed Number of GPIO pins Peripheral support (e.g., UART, SPI, I2C, timers, etc.)

    In-System Programming (ISP)

      the act of programming a microcontroller while it is already mounted on the board Contrary to Pre-Programming. You program the contro

      CMSIS-DAP Devices are all devices that can write programs into a microcontroller's memory using JTAG or SWD. ler before soldering it somewhere.

      Available Controllers

      At least 5 of each:

      • SEEEDSTUDIO XIAO SAMD21 NO HDRS
      • SEEEDSTUDIO XIAO ESP32C3 NO HDRS
      • SEEEDSTUDIO XIAO ESP32S3 NO HDRS
      • SEEED STUDIO XIAO RP2040 ARDUINO
      • ATSAMD11C14A-SSUT
      • ATSAMD21E18A-AUT
      • ATTINY412-SSFR
      • ATTINY1624-SSFR
      • ATTINY3226-SU
      • AVR128DB32-I/PT

      QFP mit Beinchen seitlich
      TQFP ohne Beinchen
      Soic-8 8 Beinchen
      Punkt oder Kerbe kennzeichnen Pin 1

      Putting code onto it

      In-System Programming (ISP)

      • the act of programming a microcontroller while it is already mounted on the board
      • Contrary to Pre-Programming. You program the contro

      CMSIS-DAP Devices are all devices that can write programs into a microcontroller's memory using JTAG or SWD. ler before soldering it somewhere.

      Serial Peripheral Interface (SPI)

      • A standard synchronous serial communication interface used for short-distance communication between a main device and one or more peripheral devices.
      • synchronous (needs clock signal), serial communication
      • multiple secondary devices are possible
      • full-duplex
      • pins:
        • MOSI (main out secondary in)
        • MISO (main in secondary out)
        • SCK (clock)
        • SS (secondary select): select which secondary device to communicate with

      Serial Peripheral Data Interface (SPDI)

      • do not find any source for it

      Joint Test Action Group (JTAG)

      • eletronics manufacturers committee
      • they developed a protocol with the same name
      • mostly used for programming ARM cores
      • pins
        • TMS: mode select
        • TCLK: clock
        • TDO: data out
        • TDI: data in
        • nRESET: reset (optional)

      Serial Wire Debug (SWD)

      • two-pin variant of the JTAG protocol
      • most common on newer ARM chips
      • pins:
        • swdio: in/out
        • swclk: clock

      Unified Program and Debug Interface (UPDI)

      • proprietary
      • single-wire,
      • bi-directional, half-duplex
      • asynchronous
      • can use off-the shelf UART adapters
      • used to program AVR microcontrollers released since 2016, ATTINY412, ATTINY164.
      • more detailed blog article
      • debugging is hidden behind a proprietary interface, but even though you can snoop on the protocol with just a serial adapter and even though the large scale structure of the protocol is known too
      • even more detailed article
      • i did not find out what part of the protocol actually is proprietary and what not.

      Difference between microcontroller and -processor

      ...

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