Texas Instruments MSP430F2121TDW

Overview

MSP430F2121TDW from Texas Instruments is an ultra-low-power 16-bit mixed-signal microcontroller featuring 4KB flash, 256B RAM, a 16-bit Timer_A with three capture/compare registers, on-chip comparator for slope A/D conversion, and operation across -40°C to 105°C. It targets battery-powered sensor nodes and portable measurement systems requiring sub-1μs wake-up and <0.1μA off-mode current.

For engineers reviewing the MSP430F2121TDW datasheet, MSP430F2121TDW pinout, MSP430F2121TDW application, or MSP430F2121TDW equivalent, key selection criteria include its 20-pin TSSOP (DW) package, calibrated DCO supporting 1–16 MHz operation, brownout detection, JTAG/emulation support, and compatibility with TI's MSP-FET430UIF debugger and MSP-TS430PW28 target board.

Technical Context

The MSP430F2121TDW implements a 16-bit RISC CPU with constant generators and seven addressing modes, enabling single-cycle register operations and high code efficiency. Its basic clock module integrates a digitally controlled oscillator (DCO), 32-kHz crystal input (XIN/XOUT), and high-frequency crystal support up to 16 MHz - all factory-calibrated to ±1% at four frequencies.

Power management includes five software-selectable low-power modes (LPM0–LPM4), with LPM4 drawing only 0.1 μA at 2.2 V. The on-chip comparator supports analog signal compare and slope ADC functionality, while Timer_A3 provides PWM generation, interval timing, and capture/compare with interrupt capability on overflow and each CCR.

Key Specifications

Pinout & Package

Package: 20-pin TSSOP (DW), body size 6.5 mm × 4.4 mm, 0.65 mm pitch, thermal pad not present (non-QFN variant).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-low-power mixed-signal microcontroller applications.

Compared with MSP430F2121TDW, the MSP430F2122TDW offers scalable memory without layout change, while the MSP430G2553IPW28 trades industrial temperature rating for richer on-chip serial peripherals and larger memory - both serve distinct design priorities in ultra-low-power embedded systems.

Availability

MSP430F2121TDW is available at Aetrix Electronics and suitable for wireless sensor nodes, battery-powered data loggers, and industrial equipment monitors requiring stable component supply and long-term lifecycle assurance.

Supply support for MSP430F2121TDW includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader delivering analog, embedded processing, and connectivity solutions with deep expertise in low-power design and precision analog integration.

The MSP430F21x1 product line was engineered for ultra-low-power portable measurement and sensing applications - emphasizing rapid wake-up, minimal active/standby current, and integrated analog peripherals to reduce external component count.

FAQ

What is the maximum operating frequency of the MSP430F2121TDW?

The MSP430F2121TDW supports a maximum MCLK frequency of 16 MHz when VCC ≥ 3.3 V and duty cycle is 50% ±10%. This is achieved using the factory-calibrated internal DCO, eliminating need for external high-frequency crystal. At lower supply voltages (e.g., 2.2 V), the maximum supported frequency reduces to 6 MHz per TI's recommended operating conditions. The MSP430F2121TDW must not be operated above these limits to ensure functional reliability.

Does the MSP430F2121TDW support hardware UART or SPI interfaces?

No, the MSP430F2121TDW does not include dedicated hardware UART, SPI, or I²C modules. Serial communication is implemented via bit-banged GPIO or through its bootstrap loader (BSL), which uses P1.1 (TX) and P2.2 (RX) for UART-based firmware updates. For native hardware serial peripherals, consider the MSP430G2553IPW28 or MSP430F2122TDW - both integrate USCI modules supporting UART/SPI/I²C.

What is the purpose of the TEST pin on the MSP430F2121TDW?

The TEST pin on the MSP430F2121TDW activates the JTAG state machine for debugging and programming. When pulled high (typically via external 47-kΩ resistor), it enables JTAG interface functionality on Port 1 pins (P1.4–P1.7). During normal operation, TEST should be externally pulled high; leaving it floating may cause unpredictable behavior. The pin is also connected to the device protection fuse and must be driven correctly during JTAG fuse-blowing procedures.

Can the MSP430F2121TDW operate from a single 1.8-V supply?

Yes, the MSP430F2121TDW is fully specified to operate from 1.8 V to 3.6 V, making it compatible with single-cell lithium-based batteries and low-voltage logic domains. At 1.8 V, maximum MCLK frequency is 6 MHz, and active-mode current drops to ~200 μA at 1 MHz. Flash programming requires minimum VCC = 2.2 V, so firmware updates must occur at ≥2.2 V - but runtime operation down to 1.8 V is fully supported and characterized.

How is the on-chip comparator used for analog-to-digital conversion in the MSP430F2121TDW?

The MSP430F2121TDW's Comparator_A+ module enables slope-based analog-to-digital conversion by charging a capacitor linearly and comparing its voltage against the input signal. The built-in 16-bit Timer_A measures the time required for the ramp to cross the threshold - directly yielding a digital value proportional to input voltage. This technique eliminates need for external ADC while maintaining 12–14 bit effective resolution depending on timing stability and noise control - ideal for slow-varying sensor signals like temperature or battery voltage.