The TM4C123 is a 32-bit ARM Cortex-M4 based microcontroller from Texas Instruments. It is part of the Tiva C Series TM4C12x family of microcontrollers designed for embedded applications requiring high performance and low power consumption.
Overview of the TM4C123
The TM4C123 features an 80 MHz 32-bit ARM Cortex-M4 CPU with floating point unit, 256KB of flash memory, 32KB of SRAM, and extensive peripheral support including Ethernet, USB, CAN, UARTs, timers, ADC, PWM, and more. It is pin-compatible with other TM4C12x MCUs allowing for easy migration between different performance and memory configurations.
Key features of the TM4C123 microcontroller include:
- 80 MHz 32-bit ARM Cortex-M4F CPU core with floating point unit
- 256KB flash memory, 32KB SRAM
- Nested Vectored Interrupt Controller
- Advanced peripheral bus architecture
- Multilayer AHB matrix interconnect
- External memory interface supporting SDRAM and flash
- Extensive peripheral support including USB, Ethernet, CAN, UARTs, timers, ADC, PWM, I2C, SPI etc.
- Operating voltage range of 3.0V to 3.6V
- Industrial temperature range of -40°C to 85°C
- Packages: 100-pin LQFP, 144-pin LQFP, 169-pin BGA
The TM4C123 MCU is targeted at industrial, medical, consumer, white goods, networking and IoT applications requiring high performance and connectivity in a small physical and low power footprint.
TM4C123 Microarchitecture
The TM4C123 is built around an 80 MHz ARM Cortex-M4F CPU core which is based on the ARMv7E-M architecture implementing the Thumb-2 instruction set. The Cortex-M4F core has an integrated floating point unit and optional DSP instructions for improved mathematical performance.
The microarchitecture includes:
- Cortex-M4F CPU Core – 80 MHz, 32-bit RISC architecture, Thumb-2 instruction set, floating point unit, optional DSP extensions
- Nested Vectored Interrupt Controller (NVIC) – Low latency interrupt handling and prioritization
- Memory Protection Unit (MPU) – Enhanced memory protection for safety critical applications
- Advanced Peripheral Bus (APB) – Bridge between CPU and peripheral modules
- Advanced High-performance Bus (AHB) – High bandwidth bus matrix connecting CPU with memory and peripherals
- External Memory Interface – Supports external flash and SDRAM
- Peripherals – Extensive peripheral set including communication interfaces, ADC, timers, PWM etc.
The Cortex-M4F provides high performance computational capability in a power efficient manner. The MPU improves software reliability in safety critical systems. The advanced bus architecture enables high bandwidth data transfers between the CPU, memories and peripherals.
TM4C123 Memory Organization
The TM4C123 contains 256KB of embedded flash memory for storing code and data. It also has 32KB of fast static RAM for data storage. In addition, the external memory interface allows connecting external memories like flash and SDRAM.
The memory layout is as follows:
- 256KB Flash – For storing code and constant data. Organized as two 128KB banks for dual-banked operation.
- 32KB SRAM – Fast data RAM accessible by CPU and DMA. Single cycle access at 80 MHz.
- External Memories – External flash and SDRAM can be accessed via the external memory interface.
- Peripherals – Peripheral registers mapped into memory address space.
The flash memory can be programmed in-system or via external programmers. Code execution occurs from flash. The SRAM provides fast access data storage without wait states. External memories provide flexibility for larger data storage requirements.
TM4C123 Peripherals and I/O
The TM4C123 includes an extensive set of peripherals and I/O interfaces for connectivity and interacting with external sensors, displays, motors and devices. Key peripherals include:
- Ethernet MAC+PHY – 10/100 Ethernet connectivity
- USB 2.0 OTG – Supports host, device and On-The-Go modes
- CAN Controller – CAN bus connectivity commonly used in industrial applications
- UARTs – Up to 8 serial ports with modem control signals
- Timers – Up to 8 general purpose timers with capture compare and PWM capabilities
- ADC – 12-bit analog to digital converter, up to 1MSPS
- Analog Comparators – For comparing analog signals
- PWM outputs – Up to 16 PWM channels with deadband generation
- Quadrature Encoder Interface – For reading position sensors
- I2C, SPI, SSI – Standard serial interfaces for connecting peripherals
The availability of multiple communication interfaces like Ethernet, USB, CAN, UARTs and I2C/SPI allows flexibility in connecting to diverse peripherals and networks. The ADCs, comparators, timers and PWM outputs are useful for interfacing with sensors and driving motors and displays.
TM4C123 Pin Configuration and Packages
The TM4C123 is available in a range of pin counts and package types to meet the needs of different applications. Key package options include:
- 100-pin LQFP – Compact 10x10mm footprint with 0.5mm pitch
- 144-pin LQFP – 16x16mm footprint with 0.4mm pitch
- 169-ball BGA – 10x10mm footprint for space constrained PCBs
The 100-pin LQFP package connects the MCU to a more limited peripheral set while the 144-pin and 169-ball packages allow interfacing with the full set of integrated peripherals. All packages support the core Cortex-M4 CPU and memory features.
The TM4C123 pins are organized into multiple peripheral function groups. Key groups include:
- Power and Ground – Power supply and returns
- Clocks and Resets – Main clock, internal oscillators, resets
- Digital I/O – General purpose and specialized digital I/O
- System Control – Boot configuration, system control, debug
- External Memory Interface – Pins for connecting external flash, RAM and peripherals
- Communication Interfaces – USB, Ethernet, CAN, UARTs etc.
- Timers, PWM, ADC – Inputs and outputs for timing, motor control, analog sensing etc.
By grouping related signals, the MCU pinout simplifies PCB layout and routing for typical embedded systems. The availability of dedicated peripheral pin groups enables interfacing with minimal external components.
TM4C123 Development Tools
Texas Instruments provides a full ecosystem of development tools for the TM4C Series MCUs including:
- IDEs – Code Composer Studio, IAR EWARM, Keil MDK-ARM
- Debug Probes – XDS110, XDS200
- Emulators – XDS560v2
- BoosterPacks – Plug-in boards for rapid prototyping
- TI-RTOS – Free RTOS for TM4C MCUs
The IDEs allow for compiling, debugging and optimizing C/C++ code for the Cortex-M4. Debug probes and emulators facilitate real-time in-system debugging and analysis. The BoosterPack ecosystem provides plug-in boards for adding functions like wireless connectivity, sensors, displays etc.
TI-RTOS provides a free to use real-time operating system for the TM4C series to simplify development. The TM4C123 LaunchPad development kit allows quick prototyping and evaluation with an on-board debugger.
TM4C123 Applications
The TM4C123 microcontroller is targeted at a wide range of embedded applications including:
- Industrial – Motor control, HMI, PLCs, instrumentation
- Consumer Electronics – Digital cameras, audio devices, printers, scanners
- Medical – Diagnostics, imaging, health monitoring
- Automotive – Automotive infotainment, gateways, telematics
- White Goods – Smart meters, washing machines, refrigerators
- Networking – Routers, switches, wireless access points
- IoT Edge Nodes – Gateways, controllers, sensor hubs
Its high performance ARM Cortex-M4F core, integrated floating point unit, and multitude of peripherals make it well suited for advanced embedded control, connectivity, signal processing and user interface applications.
Conclusion
The TM4C123 from Texas Instruments provides a highly capable 32-bit ARM Cortex-M4F core with extensive memory, peripherals, and I/O in a low power and cost effective design. With its combination of features it offers an ideal solution for demanding embedded applications in industrial, medical, networking, consumer and IoT segments.
