Texas Instruments (Tiva, MSP432, Hercules)

Texas Instruments has a complicated ARM story. They bought Luminary Micro (Stellaris — the original Cortex-M3 family), rebranded as Tiva, then deprioritised it. MSP432 (Cortex-M4F low-power) was a play to extend the MSP430 legacy and was also discontinued. Hercules (Cortex-R safety) is alive and well in automotive and industrial.

Tiva C series (was Stellaris)

The first commercially shipping Cortex-M3 was Luminary Micro's. TI bought them, rebranded to Stellaris, then to Tiva C. The TM4C123 / TM4C129 lines are widely used in academic courses (the "TIVA Launchpad" was the educational board for years) and still in production for industrial designs.

• TM4C123 — Cortex-M4F, 80 MHz, 256 KB flash, USB 2.0.
• TM4C129 — Cortex-M4F, 120 MHz, 1 MB flash, Ethernet MAC+PHY on chip.

TI's marketing focus is now more on SimpleLink (BLE, WiFi) and SitaraLinux processors, but the Tiva parts remain available for legacy designs.

MSP432 — discontinued

Marketed as the bridge from MSP430 (16-bit) to ARM Cortex-M4F. Was popular in academia. Discontinued for new designs in 2021. If you see it in older codebases, the migration target is typically Tiva C or a different vendor.

Hercules — automotive Cortex-R

The TMS570 and RM48 Hercules lines are Cortex-R4F/R5F in dual-core lockstep with extensive BIST, ECC, and ASIL-D certification artefacts. Used in:

• Airbag electronic control units.
• Antilock braking systems (ABS).
• Electric power steering (EPS).
• Industrial robotics.

Hercules ships with HALCoGen (a graphical configurator that generates HAL code) and a full safety certification package (TÜV-SÜD-evaluated, ISO 26262 ASIL D ready). The toolchain is TI's CCS (Code Composer Studio, Eclipse-based with TI's compiler) or commercial Wind River / Green Hills.

For functional-safety work, Hercules + Wind River VxWorks is a textbook combination.

SimpleLink — TI's wireless line

The CC13xx (sub-GHz + 2.4 GHz) and CC26xx (2.4 GHz / BLE) families are Cortex-M4 SoCs with integrated radio. Competitive with Nordic nRF52 for some BLE applications, with TI's strength being sub-GHz (915 MHz, 868 MHz) support that Nordic only added recently.

• CC1352 — sub-GHz + 2.4 GHz, BLE + 802.15.4 + proprietary.
• CC2640R2F / CC2650 — BLE-only.
• CC2652R — BLE + 802.15.4 (Thread / Zigbee).

The SimpleLink SDK is reasonably good — it's what you'll find in TI's reference designs and academic courses.

When you'd pick TI ARM

• Existing automotive program with Hercules tooling — very strong functional-safety story.
• Industrial with strict EMC requirements — TI's analog and PCB recommendations are top-tier.
• Sub-GHz wireless — CC13xx still has the edge over Nordic in some sub-GHz applications.
• You're heavily TI elsewhere (analog ICs, power, MCUs) — supply chain consolidation is real value.

For greenfield consumer / IoT designs, ST or Nordic typically win on ecosystem.

Hercules in depth — Cortex-R lockstep safety

Hercules is TI's flagship for IEC 61508 SIL-3 and ISO 26262 ASIL-D programs. The architectural pattern is dual-core lockstep: two identical Cortex-R4F or R5F cores execute the same instruction stream from a single fetch unit, with a small phase delay between them. A CCM-R5 (CPU Compare Module) compares architectural state cycle-by-cycle and asserts an error if they diverge. The phase delay is critical — it ensures that a transient single-event upset (cosmic ray, EMI glitch) affects only one core's state at a time and is therefore caught by the comparator rather than corrupting both cores identically.

Beyond lockstep, Hercules ships with extensive built-in self-test:

• LBIST — Logic Built-In Self-Test, exercises every flip-flop in the CPU at boot and on demand.
• PBIST — Programmable Built-In Self-Test, tests every SRAM cell with march patterns.
• ECC — Single-Error-Correct / Double-Error-Detect on every memory and every bus.
• Cross-bar parity — every AHB / VBus path has parity protection.
• Voltage and clock monitors — independent oscillator that cross-checks the main PLL.
• DCC (Dual-Clock Comparator) — verifies the system clock against an independent reference; trips a fault if drift exceeds a threshold.

The certification artefacts shipped with each Hercules part — Safety Manual, FMEDA spreadsheets, DFA (Dependent Failure Analysis) reports — represent the bulk of the value. A functional-safety auditor reads the Safety Manual first; without it, even an excellent hardware design takes years to certify. SafeTI Diagnostic Library is the TI-provided runtime code that exercises these self-tests and reports fault status.

SimpleLink wireless — the CC13xx / CC26xx architecture

SimpleLink wireless parts use a dual-core architecture that's important to understand. The application core is a Cortex-M4F (CC26x2, CC1352, CC2652) at up to 48 MHz, running the user application and most middleware. The radio core is a Cortex-M0 (or, on CC27xx, a Cortex-M33) running TI's RFCore firmware — a closed-source ROM image that implements PHY-layer packet handling. The two cores communicate through a doorbell interface and shared SRAM.

This architecture means BLE / 802.15.4 / Sub-GHz packet handling continues even when the M4F is in deep sleep. A typical BLE peripheral profile wakes the M4F only when a connection event requires application-layer processing; otherwise the M0 radio core handles connection maintenance, link-layer ACKs, and slave-latency timing. Current consumption while connected runs roughly 1–3 microamps average for a CC2640R2F.

CC1352 dual-band (sub-GHz + 2.4 GHz) is unique: the radio can switch bands within 100 microseconds, supporting concurrent multi-protocol designs where the same chip acts as a Thread border router and a 915 MHz mesh node. The newer CC2674 adds Wi-SUN support — important for utility metering.

Code Composer Studio and SimpleLink SDK

Code Composer Studio (CCS) is the TI-branded Eclipse IDE, with the TI Arm Clang compiler as the default toolchain. CCS supports SWO trace, ETM trace (on parts with the trace pins exposed), and TI's XDS110 / XDS200 debug probes that run TI's own protocol over USB. For most non-certified work, CCS is replaceable by VS Code + cortex-debug + arm-none-eabi-gcc with no real loss.

# SimpleLink SDK headless build
export SIMPLELINK_CC13X2_26X2_SDK=/path/to/sdk
make -C example/ble5_simple_peripheral

The SimpleLink SDK is decent — it uses TI's TI-RTOS (now SYS/BIOS, with a FreeRTOS option) as the kernel, with a board-specific HAL on top. The kernel selection is opinionated; if your team standardised on Zephyr, the migration cost is non-trivial.

• Cortex-R overview — Hercules R4F / R5F cores.
• Cortex-M4 — Tiva, SimpleLink M4F application core.
• Cortex-M0+ — MSPM0 entry line; SimpleLink M0 radio core.
• Cortex-M3 — original Stellaris.
• CMSIS — what TI SDKs layer over.
• NVIC priority — important for Hercules safety partitioning.
• STMicro — STM32G4 versus Tiva TM4C129 for industrial Ethernet.
• Renesas — RZ/T R52 versus Hercules trade.
• NXP — S32K versus Hercules in automotive.
• QEMU & Renode — QEMU lm3s6965evb models Stellaris; Renode covers TMS570LS.
• Interrupt latency tool — explore Hercules lockstep timing budgets.