Texas Instruments MSP430F123IRHBT

Overview

MSP430F123IRHBT from Texas Instruments is an ultralow-power 16-bit RISC mixed-signal microcontroller featuring 8KB+256B flash memory, 256B RAM, a 16-bit Timer_A with three capture/compare registers, integrated analog comparator, and USART0 supporting UART/SPI protocols. It operates from 1.8 V to 3.6 V and targets battery-powered sensor systems requiring sub-μA standby current and fast wake-up.

For engineers reviewing the MSP430F123IRHBT datasheet, MSP430F123IRHBT pinout, MSP430F123IRHBT application, or MSP430F123IRHBT equivalent, key selection criteria include its 28-pin TSSOP/RHB package compatibility, 0.1 μA LPM4 current, <6 μs wake-up time, and on-chip comparator for slope A/D conversion in resistive sensor interfaces.

Technical Context

The MSP430F123IRHBT implements a 16-bit RISC CPU with constant generators and seven addressing modes, enabling single-cycle register operations. Its basic clock module supports multiple sources: internal DCO (stabilizes in <6 μs), 32 kHz crystal, high-frequency crystal, resonator, or external clock - all configurable via BCSCTL1/2 and DCOCTL registers.

Peripherals are memory-mapped and accessible via full instruction set: Timer_A3 uses dedicated 16-bit registers (TAR, TACCR0–2, TACTL, TAIV); USART0 provides double-buffered UART/SPI with byte-access registers (U0TXBUF, U0RXBUF, U0CTL); Comparator_A connects to P2.2 (CAOUT), P2.3 (CA0), and P2.4 (CA1) for analog signal comparison or slope ADC.

Key Specifications

Pinout & Package

Package: 32-pin QFN (RHB), thermally enhanced with exposed pad recommended for connection to VSS.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MSP430F123IRHBT, the F122 offers identical ultra-low-power operation at lower memory cost, while the F2274 trades power efficiency for expanded memory, ADC, and multi-protocol communication - making the MSP430F123IRHBT optimal for cost-constrained, long-life sensor nodes where 8KB flash and comparator-based A/D meet functional requirements without over-engineering.

Availability

MSP430F123IRHBT is available at Aetrix Electronics and suitable for wireless sensor nodes, portable medical monitors, smart utility meter interfaces, and industrial condition monitors requiring stable component supply across extended product lifecycles.

Supply support for MSP430F123IRHBT 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 decades of microcontroller innovation.

The MSP430x12x product line delivers ultralow-power mixed-signal control for battery-operated measurement systems, emphasizing rapid wake-up, integrated analog functions, and minimal external component count.

FAQ

What is the maximum operating frequency of the MSP430F123IRHBT at 3.6 V?

The MSP430F123IRHBT supports a maximum system clock (MCLK) frequency of 8 MHz at 3.6 V, as specified in the recommended operating conditions. This limit applies to both CPU execution and peripheral timing derived from MCLK. The device achieves this using its digitally controlled oscillator (DCO) or external crystal/resonator sources, with DCO stabilization time remaining under 6 μs regardless of frequency setting. MSP430F123IRHBT maintains full functionality - including Timer_A3 operation, USART0 baud rate generation, and flash programming - within this 8 MHz ceiling.

Does the MSP430F123IRHBT support hardware UART or only software-emulated serial?

The MSP430F123IRHBT includes a dedicated hardware USART0 peripheral that natively supports UART mode with full duplex operation, automatic baud rate generation, and double-buffered transmit/receive registers (U0TXBUF/U0RXBUF). It does not rely on bit-banged GPIO. Hardware UART is enabled by configuring U0CTL for UART mode and setting appropriate U0BR0/U0BR1 values; it operates independently of CPU load and supports standard stop-bit, parity, and data-length configurations. MSP430F123IRHBT's UART implementation is validated for reliable communication at up to 9600 bps with 3.6 V supply and 1 MHz MCLK.

How many I/O pins does the MSP430F123IRHBT provide in the RHB (32-pin QFN) package?

The MSP430F123IRHBT in the RHB package provides 22 usable digital I/O pins: Port 1 (P1.0–P1.7) = 8 pins, Port 2 (P2.0–P2.5) = 6 pins, and Port 3 (P3.0–P3.7) = 8 pins. Although P3 has eight physical pins, all are functional I/Os - however, only P1 and P2 support edge-selectable interrupts. Pins marked NC (e.g., RHB pins 4, 17, 20, 31) are not internally connected and must remain unconnected. The exposed thermal pad is not an I/O terminal but requires connection to VSS for thermal and electrical stability. MSP430F123IRHBT's I/O count is fixed per package variant and matches the DW/PW 28-pin variants in functional capability despite differing pin counts.

Can the MSP430F123IRHBT perform analog-to-digital conversion without an external ADC?

Yes, the MSP430F123IRHBT can perform analog-to-digital conversion using its integrated Comparator_A module in slope A/D configuration. By charging a capacitor through a known resistor and measuring the time for the comparator output to toggle - timed precisely by Timer_A3 - the device converts analog voltage to digital value without external ADC components. This method leverages P2.2 (CAOUT), P2.3 (CA0), and P2.4 (CA1) with internal timing resources. MSP430F123IRHBT's slope ADC achieves effective resolution up to 12 bits depending on timer clock stability and capacitor tolerance, and is documented in TI Application Report SLAA089 for resistive sensor interfaces.

What debug and programming interfaces are supported by the MSP430F123IRHBT?

The MSP430F123IRHBT supports two primary programming interfaces: JTAG via TEST, TCK, TMS, TDI/TDO pins (P1.4–P1.7) for full-featured debugging and flash programming, and the UART-based Bootstrap Loader (BSL) using P1.1 (TX) and P2.2 (RX) for production firmware updates without JTAG hardware. Both methods support flash memory programming, RAM initialization, and security fuse configuration. MSP430F123IRHBT's BSL is password-protected and resides in ROM, ensuring robust field updates. No SWD or cJTAG support is provided - JTAG and BSL are the only validated interfaces per SLAS312C datasheet.