The ARM Cortex series refers to ARM processor cores designed by Arm Holdings for use in a variety of devices including microcontrollers. However, the ARM Cortex cores themselves are not standalone microcontrollers. Rather, they are CPU cores that get incorporated into system-on-a-chip (SoC) designs by semiconductor companies to make complete microcontroller units.
So in summary, the ARM Cortex cores by themselves are not microcontrollers, but they do get widely used in microcontroller SoC designs from various semiconductor manufacturers. The Cortex cores provide the processing capabilities while other components like memory, peripherals, etc get added around the core to create a full microcontroller solution.
What is an ARM Cortex core?
ARM Cortex refers to a series of processor cores designed by ARM Holdings based on the ARM instruction set architecture. ARM offers these core designs to semiconductor companies who can then integrate the cores into their own system-on-a-chip (SoC) products.
The ARM Cortex cores contain the CPU (central processing unit) that handles the processing tasks. But the cores do not contain other components like memory, peripherals, etc that would make them complete microcontroller solutions.
Instead, companies licensing and using the ARM Cortex cores will combine the core with additional components like RAM, ROM, peripherals, interfaces, etc to create a full microcontroller chip. So the ARM Cortex cores provide the processing brains, while the licensee adds the other pieces needed for a functional microcontroller product.
Common ARM Cortex cores used in microcontrollers
Some of the most popular ARM Cortex cores used in microcontroller designs include:
- Cortex-M0 – Ultra low power 32-bit MCU core
- Cortex-M0+ – Enhanced M0 core with higher performance
- Cortex-M3 – Mainstream 32-bit core with DSP instructions
- Cortex-M4 – High performance MCU core with DSP and FPU
- Cortex-M7 – Highest performance M-series core
- Cortex-M23 – Ultra low power MCU core with microcontroller features
- Cortex-M33 – High efficiency MCU core with TrustZone and DSP
These ARM CPU cores get integrated into microcontroller chip designs across many different semiconductor manufacturers. Some examples include:
- STM32 series from STMicroelectronics using Cortex-M cores
- LPC series from NXP using Cortex-M cores
- SAM series from Microchip using Cortex-M cores
- EFM32 series from Silicon Labs using Cortex-M cores
- Kinetis series from NXP using Cortex-M cores
The specific ARM core used depends on the performance, power, and feature requirements of the target application. But in all cases, the semiconductor company takes the ARM CPU core and adds additional components to create a full microcontroller solution.
Key differences between an ARM Cortex core and a microcontroller
The key differences between an ARM Cortex core and a complete microcontroller include:
- ARM Cortex is just the CPU core while a microcontroller contains CPU plus added components like memory, peripherals, interfaces, etc.
- Cortex cores have to be combined with other blocks to make a functional IC, whereas microcontrollers are self-contained on a single chip.
- Cortex cores by themselves can’t execute code or applications. A microcontroller can run embedded software out of the box.
- Cortex cores only provide computation abilities. A microcontroller includes computation along with I/O, connectivity, power management, and more.
- ARM sells Cortex IP cores to semiconductor companies. Microcontrollers are full chip products sold to end users.
In summary, the ARM Cortex cores provide the processing brains but are not standalone microcontrollers. Microcontroller products integrate a Cortex core along with many other components required for an embedded application solution.
How ARM Cortex cores are combined into microcontrollers
Semiconductor companies who license ARM Cortex cores combine them with additional hardware blocks to create full microcontroller ICs. Here is a high-level overview of how this process works:
- The company licenses one or more ARM Cortex CPU cores to use in their design.
- They add RAM and ROM memory blocks around the core to hold program data and code.
- Peripheral devices like timers, ADCs, UARTs, I2C, etc are added to provide I/O capabilities.
- Interconnect logic like bus fabric and memory interfaces are added to connect the components.
- Debug and programming logic is added to load code and monitor the chip.
- Clocks, resets, and power circuitry are added for proper management.
- Any special function hardware needed is designed in like crypto blocks.
- The chip is laid out and routed to connect all the logic and components.
- The finished design goes to manufacturing for IC fabrication.
In this way the microcontroller company builds up all the hardware necessary around the ARM core to create a functional MCU product. The ARM core enables software-based functionality, while the hardware blocks enable I/O, connectivity, real-time control, and more in a compact single-chip design.
Benefits of using ARM Cortex cores
There are several benefits semiconductor companies gain by using ARM’s Cortex cores in their microcontroller products:
- Proven, pre-designed CPU cores enable faster time-to-market.
- ARM’s extensive software and tool ecosystem supports development.
- Ability to leverage ARM’s roadmap for future core enhancements.
- Focus R&D investment on custom blocks instead of core design.
- Gain high performance and power efficient CPU technology.
- Scalable options for different cost, performance, and power needs.
By leveraging ARM’s CPU cores and surrounding them with their own logic, companies can bring robust microcontroller solutions to market faster and more cost effectively than designing a full custom architecture from scratch.
In summary, the ARM Cortex CPU cores provide processing capabilities but are not standalone microcontrollers. Microcontroller products from top semiconductor vendors integrate ARM processor cores along with numerous other components required for a complete embedded system solution. The ARM cores provide software-based functionality while the hardware integration enables real-time I/O, connectivity, and control capabilities demanded by embedded applications. Through integration with ARM’s proven CPU cores, microcontroller companies can deliver high performance, power efficient system-on-chip solutions to meet demanding embedded computing requirements.