STMicroelectronics ST72F324LJ4T6TR

Overview

ST72F324LJ4T6TR from STMicroelectronics is an 8-bit Flash-based microcontroller in the ST72324Lxx family, operating in the 2.85–3.6 V range with -40°C to +85°C industrial temperature rating. It integrates 8 KB Flash/ROM, 384 bytes RAM (256-byte stack), 10-bit ADC with up to 12 input channels, four timers (including 16-bit Timer A/B), SPI and SCI serial interfaces, and a PLL for 2× frequency multiplication. It targets embedded control in motor drives, sensor nodes, and industrial I/O modules.

For engineers reviewing the ST72F324LJ4T6TR datasheet, ST72F324LJ4T6TR pinout, ST72F324LJ4T6TR application, or ST72F324LJ4T6TR equivalent, this MCU delivers deterministic real-time control with nested interrupts, multiple low-power modes (Halt, Wait, Slow), high-sink I/O (12 lines), and in-application programming support - critical for field-upgradable firmware in cost-sensitive industrial designs.

Technical Context

The ST72F324LJ4T6TR implements the ST7 CPU core with 63 basic instructions and 17 addressing modes, including 8×8 unsigned multiply. Its clock system supports crystal/ceramic resonator (up to 8 MHz), internal RC oscillator, and external clock bypass, with a PLL enabling 16 MHz CPU operation from an 8 MHz source.

Interrupt handling uses a nested controller with 10 vectors plus TRAP and RESET, supporting up to 9 external interrupt lines across 4 vectors. Peripheral integration includes a configurable watchdog timer, main clock controller with RTC/beeper, and dual 16-bit timers offering input capture, output compare, PWM, and pulse generation - all accessible via dedicated registers mapped in the 64 KB address space.

Key Specifications

Pinout & Package

LQFP44 package (10 mm × 10 mm, 0.8 mm pitch), RoHS-compliant, with 32 multifunctional I/O lines, 22 alternate function pins, and 12 high-sink outputs (20 mA per pin).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit microcontroller applications.

Compared with STM8S003F3P6 and EFM8BB10F8G-A-QSOP24, the ST72F324LJ4T6TR uniquely combines RTC, beeper, dual 16-bit timers, and 32 I/O in LQFP44 - making it optimal for legacy-compatible industrial controllers requiring precise timing and direct actuator drive.

Availability

ST72F324LJ4T6TR is available at Aetrix Electronics and suitable for motor control interfaces, industrial sensor nodes, PLC I/O modules, and smart power outlets requiring stable component supply across extended product lifecycles.

Supply support for ST72F324LJ4T6TR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power ICs, sensors, and analog devices for industrial, automotive, and consumer markets.

The ST72324Lxx product line was engineered for cost-sensitive, real-time embedded control in industrial automation and appliance applications - emphasizing Flash flexibility, low-voltage operation, and integrated peripherals to minimize external components.

FAQ

What is the maximum operating frequency of the ST72F324LJ4T6TR?

The ST72F324LJ4T6TR achieves a maximum CPU frequency of 16 MHz using its internal PLL, which multiplies an 8 MHz external crystal or resonator input by 2×. Without PLL, the maximum frequency is 8 MHz. The PLL is enabled via the CLKDIV register and requires stable clock startup sequencing per Section 6.1 of the datasheet.

Does the ST72F324LJ4T6TR support in-circuit programming (ICP)?

Yes, the ST72F324LJ4T6TR supports In-Circuit Programming via the ICC interface using the dedicated ICCSEL/VPP pin and standard ST-LINK or compatible programmers. ICP allows full Flash/option byte programming without removing the device from the PCB, and requires no special boot code - the MCU enters programming mode upon correct voltage and timing on ICCSEL.

How many analog input channels does the 10-bit ADC support?

The integrated 10-bit ADC supports up to 12 analog input channels, mapped to port pins PA0–PA7, PB0–PB3, and optionally PC0–PC1 depending on configuration. Channel selection is controlled by the ADCCSR register, and conversion can be triggered automatically by timer overflow or software write, with results stored in the 16-bit ADCH/ADCL registers.

Can the ST72F324LJ4T6TR operate from a single 3.3 V supply?

Yes, the ST72F324LJ4T6TR operates across 2.85 V to 3.6 V, making it fully compatible with standard 3.3 V LDOs or DC-DC converters. At 3.3 V, typical active current is 8 mA at 8 MHz (no peripherals), and the internal RC oscillator remains stable within ±10% - sufficient for non-timing-critical functions like LED control or button scanning.