Texas Instruments MSP430G2121IRSA16T

Overview

MSP430G2121IRSA16T from Texas Instruments is an ultra-low-power 16-bit RISC microcontroller featuring 1 kB Flash, 128 B RAM, a 16-bit Timer_A with two capture/compare registers, brownout detection, and five power-saving modes. It operates from 1.8 V to 3.6 V and delivers active-mode current of 220 µA at 1 MHz/2.2 V - optimized for battery-powered sensor nodes and portable instrumentation.

For engineers reviewing the MSP430G2121IRSA16T datasheet, MSP430G2121IRSA16T pinout, MSP430G2121IRSA16T application, or MSP430G2121IRSA16T equivalent, this page provides verified functional identity, QFN-16 package mapping, validated I/O pin roles, confirmed low-power timing behavior, and two technically documented alternative parts for design continuity.

Technical Context

The MSP430G2121IRSA16T implements a 16-bit CPU with constant generators and seven addressing modes, enabling single-cycle register operations. Its clock system integrates a digitally controlled oscillator (DCO), internal very-low-power LF oscillator, and optional 32-kHz crystal support - all configurable via BCSCTL registers to generate ACLK, MCLK, and SMCLK.

It includes Spy-Bi-Wire on-chip emulation logic, universal serial interface (USI) supporting SPI and I²C protocols, and programmable digital I/O across Port P1 (8 pins) and Port P2 (2 pins), each with individually configurable pull-up/down resistors and edge-selectable interrupts.

Key Specifications

Pinout & Package

Package: 16-pin QFN (RSA), 4 mm × 4 mm, 0.65 mm pitch, exposed thermal pad connected to DVSS.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MSP430G2221IRSA16 and MSP430G2121IPW14, the MSP430G2121IRSA16T provides optimal cost/power balance for fixed-function sensor controllers where Flash headroom and QFN miniaturization are primary drivers.

Availability

MSP430G2121IRSA16T is available at Aetrix Electronics and suitable for wireless sensor nodes, portable medical monitors, smart utility meter interfaces, and industrial control panels requiring stable component supply and long-term industrial temperature support.

Supply support for MSP430G2121IRSA16T 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 specializing in analog, embedded processing, and connectivity technologies with over 90 years of innovation in low-power design.

The MSP430G2xx family targets ultra-low-power mixed-signal applications - specifically engineered for battery-operated sensing, measurement, and control systems where energy efficiency and integration are critical.

FAQ

What is the maximum operating frequency of the MSP430G2121IRSA16T?

The MSP430G2121IRSA16T supports a maximum MCLK frequency of 16 MHz at VCC ≥ 3.3 V, 12 MHz at VCC ≥ 2.7 V, and 6 MHz at VCC = 1.8 V. This is governed by DCO calibration and supply voltage - the device uses factory-trimmed CALBC1_1MHZ and CALDCO_1MHZ values stored in Info Memory Segment A to achieve stable operation across its voltage range. The MSP430G2121IRSA16T does not include an ADC10 module, distinguishing it from G2x31 variants.

Does the MSP430G2121IRSA16T support hardware I²C communication?

Yes, the MSP430G2121IRSA16T supports hardware I²C via its Universal Serial Interface (USI) module. Pins P1.6 (SCL) and P1.7 (SDA) provide dedicated I²C functionality when USICTL0 and USICTL1 registers are configured for I²C mode. The USI handles clock stretching, arbitration, and START/STOP condition generation autonomously - no CPU polling or bit-banging is required for compliant I²C transactions.

How many I/O pins does the MSP430G2121IRSA16T have, and what are their capabilities?

The MSP430G2121IRSA16T provides 10 total I/O pins: eight bits on Port P1 (P1.0–P1.7) and two bits on Port P2 (P2.6, P2.7). Each pin supports individually programmable direction, input latch, output driver, pull-up/pull-down resistor, and edge-selectable interrupt. P1 pins also support secondary functions including Timer_A signals, USI lines, and JTAG/Spy-Bi-Wire - all controlled via P1SEL and P2SEL registers.

What low-power modes are available on the MSP430G2121IRSA16T, and how do they differ?

The MSP430G2121IRSA16T offers five software-selectable low-power modes (LPM0–LPM4). LPM0/LPM1 disable CPU but retain SMCLK/ACLK; LPM2 stops SMCLK but keeps ACLK active; LPM3 disables MCLK/SMCLK and runs only on ACLK or VLO; LPM4 shuts down all clocks including ACLK and stops the crystal oscillator. Current draw ranges from 65 µA (LPM0 @ 1 MHz) to 0.1 µA (LPM4), with wake-up latency under 1 µs from LPM3/LPM4 using the DCO.

Is the MSP430G2121IRSA16T pin-compatible with other devices in the MSP430G2xx family?

Yes, the MSP430G2121IRSA16T shares identical pinout and electrical characteristics with other RSA-package devices in the G2x21/G2x31 families, including MSP430G2221IRSA16 and MSP430G2131IRSA16. All use the same 16-pin QFN layout, power/ground placement, and I/O mapping - enabling drop-in replacement where Flash size, ADC presence, or Timer_A channel count align with system requirements.