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Home > Products > Integrated Circuits (ICs) > Embedded > Microcontrollers

STMicroelectronics ST72F321J7T6

Name: ST72F321J7T6
Brand: STMicroelectronics
SKU: ST72F321J7T6
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ST72F321J7T6

Manufacturer:: STMicroelectronics

Category:: Microcontrollers

Package:: 44-LQFP

Datasheet:: ST72F321J7T6.pdf

Description:: IC MCU 8BIT 48KB FLASH 44LQFP

Quantity:: RFQ Add To RFQ list

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Inventory:1,344

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Product details

Overview

ST72F321J7T6 from STMicroelectronics is a 44-pin LQFP 8-bit microcontroller featuring 48KB Flash/ROM, 1.5KB RAM, 10-bit ADC with up to 16 channels, five timers (including PWM auto-reload and dual 16-bit), and three serial interfaces (SPI, SCI, I²C). It operates from 3.8V to 5.5V across –40°C to +85°C and targets industrial motor control, sensor interface modules, and embedded power management systems.

For engineers reviewing the ST72F321J7T6 datasheet, ST72F321J7T6 pinout, ST72F321J7T6 application, or ST72F321J7T6 equivalent, this MCU delivers deterministic real-time control with nested interrupts, four low-power modes (Halt, Active-Halt, Wait, Slow), and in-application programming support for field firmware updates in resource-constrained embedded designs.

Technical Context

The ST72F321J7T6 integrates a 16MHz max CPU core with PLL-based 2× frequency multiplication, enabling precise timing for synchronous peripherals like SPI and I²C. Its clock system supports crystal, ceramic resonator, internal RC, and external clock inputs - with configurable low-voltage detection (LVD) and auxiliary voltage detection (AVD) for robust supply monitoring.

Interrupt handling uses a nested controller with 14 vectors plus TRAP and RESET, supporting up to 9 external interrupt lines on 4 vectors. The device implements 32 multifunctional I/O ports (22 alternate function lines, 12 high-sink outputs), enabling flexible peripheral routing without external glue logic in compact industrial controllers.

Key Specifications

Parameter	Value and Actual Design Meaning
CPU Core	8-bit ST7 architecture with 63 instructions and 17 addressing modes - enables compact code footprint and deterministic interrupt latency critical for real-time motor commutation.
Flash Memory	48KB HDFlash with 100 write/erase cycles and 40-year data retention at 85°C - supports secure in-application programming for field-upgradable firmware.
RAM	1536 bytes (1.5KB) including 256-byte stack - sufficient for nested ISR execution and small real-time task buffers in standalone control nodes.
ADC	10-bit SAR ADC with up to 16 input channels and programmable sampling time - provides accurate analog sensing for temperature, current, and voltage feedback loops.
Timers	Five independent timers: main clock controller (RTC/beep/clock-out), configurable watchdog, two 16-bit timers (input capture/output compare/PWM), and 8-bit PWM auto-reload timer with 4 outputs - enables simultaneous motor PWM, encoder counting, and system supervision.
Serial Interfaces	SPI (master/slave), SCI (asynchronous UART), and I²C multimaster - allows direct connection to sensors, displays, EEPROMs, and host controllers without protocol translation.
Supply Range	3.8V to 5.5V operating voltage with LVD and AVD interrupt capability - ensures reliable operation across industrial power rails and brown-out resilience.

Pinout & Package

LQFP44 10 × 10 mm package with exposed pad (RoHS-compliant), 0.8 mm pitch, and thermal performance suitable for convection-cooled industrial PCBs.

Pin/Terminal	Circuit Role	Design Meaning
VDD, VSS	Power supply and ground	Dual power pins ensure stable core and I/O rail decoupling; mandatory 100nF ceramic capacitor per VDD pin near package.
OSCIN/OSCOUT	Crystal/resonator interface	Supports 1–16 MHz crystals or ceramic resonators; internal load capacitors eliminate need for external caps in basic configurations.
PA0–PA7	Port A bidirectional I/O	8-bit port with alternate functions including SPI MOSI/MISO, SCI TX/RX, and ADC inputs - enables consolidated peripheral mapping.
PB0–PB7	Port B bidirectional I/O	8-bit port supporting external interrupt lines, timer input captures, and PWM outputs - used for encoder inputs and actuator drive signals.
PC0–PC7	Port C bidirectional I/O	8-bit port with I²C SDA/SCL, ADC triggers, and high-sink capability (20 mA per pin) - drives LEDs or small relays directly.
PD0–PD7	Port D bidirectional I/O	8-bit port with reset, clock-out, and watchdog feed - provides debug visibility and fail-safe reset coordination.
NRST	Active-low reset input	Asynchronous external reset with internal pull-up; accepts 10 µs minimum pulse width for reliable system initialization.

Key Features

Feature	Design Value
In-Application Programming (IAP)	Enables firmware updates via SCI or SPI without removing MCU from board - reduces maintenance downtime in deployed equipment.
Four Power Saving Modes	Halt (CPU stopped, peripherals active), Active-Halt (CPU halted, RAM retained), Wait (clock gated, wake on interrupt), and Slow (reduced system clock) - extends battery life in portable diagnostics tools.
Nested Interrupt Controller	14 priority-level vectors with automatic context save/restore - guarantees sub-2 µs response to critical events like overcurrent faults.
High-Sink I/O Outputs	12 pins capable of sinking 20 mA each - directly drives indicators, optocouplers, or gate drivers without external transistors.
Real-Time Clock & Beeper	Integrated RTC with calendar mode and programmable beep generator - eliminates external timing ICs in HMI and alarm systems.

Applications

Industrial Motor Control

Sensor Interface Module

Use Scenario: Brushless DC motor commutation in HVAC blowers with Hall-effect rotor position feedback.

IC Role / Device Role / Timing Role: Real-time PWM generation, ADC-based current sensing, and encoder input capture using dual 16-bit timers and 10-bit ADC.

Use Value: Precise 15 kHz PWM switching synchronized to rotor position enables >92% efficiency and low acoustic noise without external timing ICs.

Use Scenario: Multi-sensor node aggregating temperature, humidity, and pressure data for building automation.

IC Role / Device Role / Timing Role: Central data acquisition unit with I²C sensor polling, SPI flash logging, and SCI UART telemetry uplink.

Use Value: Integrated 16-channel ADC and three serial interfaces reduce BOM count by 4 components versus discrete interface solutions.

Embedded Power Management

Programmable Logic Controller (PLC) I/O Module

Use Scenario: AC/DC power supply supervisor with overvoltage, overtemperature, and fan-failure detection.

IC Role / Device Role / Timing Role: System monitor using LVD/AVD interrupts, watchdog timeout supervision, and GPIO-driven fault latching.

Use Value: Single-chip supervision replaces discrete comparators and timers, cutting PCB area by 35% and improving fault-response consistency.

Use Scenario: DIN-rail mounted digital I/O expansion module with 16 isolated inputs and 8 relay outputs.

IC Role / Device Role / Timing Role: Local intelligence hub managing opto-isolated inputs, driving relay drivers, and communicating via RS-485 SCI link.

Use Value: 32 I/O lines with high-sink capability eliminate external driver ICs for relay coils, reducing component count and thermal stress.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
STM8S105K4T6	16MHz STM8 core, 16KB Flash, 2KB RAM, no PLL, single 16-bit timer, no dedicated beeper	Lacks RTC/beeper and second 16-bit timer; lower Flash density limits complex control algorithms	Preferred for cost-sensitive, low-complexity sensor nodes where beeper and dual-timer features are unused
EFM8BB52F16G-A-QFP48	8051-based, 16KB Flash, 2.25KB RAM, 12-bit ADC, hardware CRC, USB interface	Higher ADC resolution but no native I²C multimaster; USB adds complexity for non-hosted systems	Selected when USB device connectivity or cryptographic checksums are required, accepting trade-off in I²C flexibility

Compared with STM8S105K4T6 and EFM8BB52F16G-A-QFP48, the ST72F321J7T6 uniquely balances legacy ST7 software compatibility, integrated beeper/RTC, and dual 16-bit timers - making it optimal for retrofitting existing ST7-based motor control firmware while retaining full peripheral feature set.

Availability

ST72F321J7T6 is available at Aetrix Electronics and suitable for industrial motor control, sensor interface modules, and embedded power management requiring stable component supply through extended product lifecycles.

Supply support for ST72F321J7T6 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 devices, sensors, and analog ICs for automotive, industrial, and consumer markets.

The ST7 family was engineered for deterministic real-time control in cost-sensitive industrial applications, emphasizing low-latency interrupt response, integrated analog peripherals, and field-programmable Flash memory - targeting motor drives, appliance controls, and building automation.

FAQ

What is the maximum operating frequency of the ST72F321J7T6?

The ST72F321J7T6 supports a maximum CPU clock frequency of 16 MHz, achievable via its internal PLL that multiplies the base oscillator frequency by 2×. This allows full-speed execution of instruction cycles and precise timing for PWM, ADC sampling, and serial communication baud rates without external clock generators.

Does the ST72F321J7T6 support in-circuit programming (ICP)?

Yes, the ST72F321J7T6 supports In-Circuit Programming (ICP) through its built-in bootloader using the SCI interface. It requires only the NRST pin and SCI TX/RX lines for programming - no external debugger hardware is needed, enabling factory programming and field firmware updates via standard UART connections.

How many I/O pins support external interrupt capability?

The ST72F321J7T6 provides 9 dedicated external interrupt lines mapped across 4 interrupt vectors (INT0–INT3), with sensitivity configurable per pin for rising/falling/both edges. These lines are distributed across Ports A, B, and D, allowing concurrent edge-triggered event detection from multiple sensors or switches.

What is the ADC's effective sampling rate and resolution?

The ST72F321J7T6 features a 10-bit successive approximation ADC with up to 16 input channels and a maximum conversion rate of 1 MSPS under optimal conditions. Its resolution is fixed at 10 bits, delivering 1 LSB = VREF/1024, with programmable sampling time to accommodate varying source impedances in industrial signal conditioning.

ST72F321J7T6 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Package/Case:: 44-LQFP

Series:: ST7

Packaging:: Tray

Product Status:: Obsolete

Programmable:: Not Verified

Core Processor:: ST7

Core Size:: 8-Bit

Speed:: 8MHz

Connectivity:: I2C, SCI, SPI

Peripherals:: LVD, POR, PWM, WDT

Number of I/O:: 32

Program Memory Size:: 48KB (48K x 8)

Program Memory Type:: FLASH

EEPROM Size:: -

RAM Size:: 1.5K x 8

Voltage - Supply (Vcc/Vdd):: 3.8V ~ 5.5V

Data Converters:: A/D 16x10b

Oscillator Type:: Internal

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:

ST72F321J7T6 FAQ

1.How can I place an order for ST72F321J7T6 through Aetrix?

Please submit a Request for Quotation (RFQ) for ST72F321J7T6 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for ST72F321J7T6 reliable?

The price and inventory of ST72F321J7T6 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ST72F321J7T6 is usually 5 days.

3.What payment methods are accepted for ST72F321J7T6?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ST72F321J7T6 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ST72F321J7T6?

ST72F321J7T6 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ST72F321J7T6 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for ST72F321J7T6?

For technical support, including ST72F321J7T6 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ST72F321J7T6 requirements.

6.How does Aetrix verify that ST72F321J7T6 is sourced from the original manufacturer or authorized distributors?

All ST72F321J7T6 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that ST72F321J7T6 meets industry standards.

7.What is the process for return or replacement of ST72F321J7T6?

All ST72F321J7T6 units undergo pre-shipment inspection (PSI). If there is an issue with ST72F321J7T6, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The ST72F321J7T6 part is unused and in its original packaging.

Return procedure for ST72F321J7T6:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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