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

STMicroelectronics ST72F321BK6T6TR

Name: ST72F321BK6T6TR
Brand: STMicroelectronics
SKU: ST72F321BK6T6TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ST72F321BK6T6TR

Manufacturer:: STMicroelectronics

Category:: Microcontrollers

Package:: 32-LQFP

Datasheet:: ST72F321BK6T6TR.pdf

Description:: IC MCU 8BIT 32KB FLASH 32LQFP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

ST72F321BK6T6TR from STMicroelectronics is a 44-pin LQFP 8-bit microcontroller featuring 32KB Flash/ROM, 1KB RAM, 10-bit ADC with up to 16 inputs, 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 +125°C and targets automotive body control modules requiring robust timing, analog sensing, and low-power operation.

For engineers reviewing the ST72F321BK6T6TR datasheet, ST72F321BK6T6TR pinout, ST72F321BK6T6TR application, or ST72F321BK6T6TR equivalent, this device supports in-application programming (IAP), nested interrupts with 14 vectors, enhanced low-voltage detection (LVD/AVD), and four power-saving modes - critical for battery-backed or thermally constrained embedded systems.

Technical Context

The ST72F321BK6T6TR implements the ST7 core with 63 basic instructions and 17 addressing modes, including 8×8 unsigned multiply. Its clock system integrates an internal RC oscillator, crystal/ceramic resonator support, external clock bypass, and a 2× PLL for frequency multiplication - enabling flexible clock tree design without external multipliers.

Interrupt handling uses a nested controller with top-level interrupt (TLI) capability on 64-pin variants (not present here), 15 external interrupt lines mapped to 4 vectors, and configurable priority. Peripheral integration includes a main clock controller (MCC) with real-time base, beep generator, and clock-out function - all accessible via dedicated registers and interrupt sources.

Key Specifications

Parameter	Value and Actual Design Meaning
Core Architecture	ST7 8-bit RISC CPU with 63 instructions and 17 addressing modes - enables compact firmware and deterministic timing for real-time control loops.
Flash Memory	32KB HDFlash with read-out protection and 100-cycle endurance - supports field firmware updates via IAP and secure IP retention.
RAM Size	1024 bytes (1KB) with 256-byte stack - sufficient for interrupt nesting and small real-time task stacks in automotive sensor nodes.
ADC Resolution	10-bit SAR ADC with up to 16 input channels - delivers ±1 LSB INL for precise temperature, voltage, or potentiometer monitoring.
Timers	Five independent timers: MCC/RTC, configurable watchdog, two 16-bit (input capture/output compare/PWM), and 8-bit PWM auto-reload - supports motor control, PWM dimming, and time-stamped event logging.
Communication Interfaces	SPI (master/slave), SCI (asynchronous UART), and I²C (multimaster) - enables connectivity to sensors, displays, EEPROMs, and CAN transceivers via bridging.
Operating Voltage	3.8V to 5.5V - compatible with 5V automotive supply rails and tolerant of transient load-dump conditions when paired with external regulators.
Temperature Range	–40°C to +125°C - qualified for under-hood automotive applications including door modules and lighting controllers.

Pinout & Package

LQFP44 package (10 × 10 mm, 0.8 mm pitch) with exposed thermal pad (non-electrical). Pin count and signal mapping conform to ST72321BKx series pin compatibility across 44-pin variants.

Pin/Terminal	Circuit Role	Design Meaning
VDD, VSS	Power supply and ground	Dual power domains: VDD powers core/peripherals; VSS provides low-noise reference for ADC and analog comparators.
PA0–PA7, PB0–PB7, PC0–PC7, PD0–PD7	Bi-directional I/O ports	48 total I/O lines (32 usable on LQFP44); up to 22 alternate functions (e.g., SPI_MOSI, SCI_TX, I²C_SCL) - enables multiplexed peripheral routing.
OSCIN/OSCOUT	Clock input/output	Drives external crystal (1–8 MHz) or ceramic resonator; supports bypass mode for external clock injection at up to 16 MHz.
RESET	Active-low reset input	Asynchronous external reset with internal pull-up; triggers full system initialization and clears all registers and RAM.
BOOT	Boot mode selection	Configures boot vector location (system memory vs. user Flash) during power-on - essential for bootloader implementation and firmware recovery.
TLI	Top Level Interrupt input	Not available on LQFP44 package - reserved for 64-pin variants only; omitted in this device's pinout.

Key Features

Feature	Design Value
In-Application Programming (IAP)	Enables firmware updates over SCI or SPI without external programmer - reduces service downtime in deployed automotive ECUs.
Enhanced Low-Voltage Detection (LVD)	Monitors main supply and auxiliary voltage with interrupt generation - prevents erratic behavior during brown-out or battery sag in vehicle power systems.
Four Power-Saving Modes	Halt, Active-Halt, Wait, Slow - reduce current consumption to <1 µA (Halt) while retaining RAM and register state for fast wake-up from external interrupts.
10-Bit ADC with 16 Inputs	Supports simultaneous sampling across multiple channels using scan mode - ideal for multi-sensor cabin monitoring (temperature, humidity, light).
Nested Interrupt Controller	14 vectored interrupts plus TRAP/RESET with programmable priority - ensures deterministic response to safety-critical events like overcurrent or thermal shutdown.

Applications

Automotive Door Control Module

Industrial HVAC Sensor Node

Use Scenario: Centralized control of window lift, mirror adjustment, and interior lighting in passenger vehicles.

IC Role / Device Role / Timing Role: Main system controller executing motor drive logic, switch debouncing, LIN communication, and real-time fault monitoring.

Use Value: Integrated 16-bit timers enable precise PWM for BLDC window motors; 10-bit ADC reads potentiometer position feedback with ±1 LSB accuracy.

Use Scenario: Wireless-capable environmental monitoring unit measuring temperature, CO₂, and airflow in commercial HVAC ducts.

IC Role / Device Role / Timing Role: Sensor fusion hub aggregating analog and digital inputs, managing sleep/wake cycles, and formatting data for RF transmission.

Use Value: Four power-saving modes extend battery life to >5 years; I²C interface connects directly to digital temperature/humidity sensors (e.g., HTU21D).

Smart Lighting Driver

Appliance Motor Control Board

Use Scenario: Dimmable LED driver for commercial downlights with DALI or 0–10V analog interface.

IC Role / Device Role / Timing Role: PWM generator and communication bridge translating DALI commands into high-frequency LED current modulation.

Use Value: 8-bit PWM auto-reload timer delivers 4 independent outputs with 1% duty cycle resolution - eliminates external PWM ICs.

Use Scenario: Brushless DC motor control in premium kitchen appliances (e.g., blenders, food processors).

IC Role / Device Role / Timing Role: Commutation sequencer using input capture for rotor position sensing and output compare for gate drive timing.

Use Value: Dual 16-bit timers provide synchronized 3-phase PWM with dead-time insertion - reduces BOM cost versus dedicated motor ICs.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ST72F324K6T6	48KB Flash, 1.5KB RAM, same LQFP44 package and peripheral set - higher memory headroom for complex control algorithms.	Preferred for applications requiring larger firmware (e.g., OTA update stacks or cryptographic libraries).	Select when future firmware expansion is anticipated; pin-compatible but requires Flash layout revalidation.
STM8AF5269	STM8 core, 32KB Flash, 2KB RAM, extended –40°C to +150°C AEC-Q100 Grade 1 qualification - superior automotive reliability and toolchain continuity.	Required for new automotive designs targeting ASIL-B compliance or long-term production stability.	Choose for new automotive programs needing AEC-Q100 certification and modern tool support; not pin-compatible.

Compared with ST72F321BK6T6TR, ST72F324K6T6 offers memory scalability within identical hardware constraints, while STM8AF5269 provides certified automotive robustness and lifecycle assurance - making the latter essential for safety-critical deployments despite requiring PCB redesign.

Availability

ST72F321BK6T6TR is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor nodes, smart lighting systems, and appliance motor control requiring stable component supply and long-term manufacturability.

Supply support for ST72F321BK6T6TR 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 cost-sensitive, real-time embedded control in harsh environments - emphasizing low-power operation, integrated analog peripherals, and robust interrupt handling for automotive and industrial edge nodes.

FAQ

Is ST72F321BK6T6TR supported by current ST development tools?

Yes - STVD (ST Visual Develop) and STVP (ST Visual Programmer) fully support this device for debugging, flash programming, and configuration. While ST no longer actively develops ST7 toolchains, both tools remain downloadable from ST's legacy archive and function on Windows 10/11 with USB-to-serial adapters. No official STM32CubeIDE support exists.

What is the maximum operating frequency achievable with the internal PLL?

The PLL provides 2× frequency multiplication of the input clock source. With a maximum external crystal frequency of 8 MHz, the PLL delivers up to 16 MHz system clock. The internal RC oscillator (8 MHz nominal) can also be multiplied, but its tolerance (±10%) limits timing-critical applications unless calibrated against an external reference.

Does ST72F321BK6T6TR include hardware CRC or encryption acceleration?

No - this device lacks dedicated hardware CRC computation or cryptographic accelerators. All checksum and security operations must be implemented in firmware using standard ST7 arithmetic instructions. For secure boot or data integrity, software-based CRC-16 or CRC-32 routines are required, consuming CPU cycles and Flash space.

Can the 10-bit ADC operate during low-power modes?

Yes - the ADC remains functional in Wait and Active-Halt modes, allowing background conversions triggered by timer events or external interrupts. However, it is disabled in Halt and Slow modes. Wake-up from Halt requires external interrupt or RESET; ADC conversion results are preserved in registers upon wake-up if configured before entering Halt.

ST72F321BK6T6TR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Package/Case:: 32-LQFP

Series:: ST7

Packaging:: Tape & Reel (TR)

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:: 24

Program Memory Size:: 32KB (32K x 8)

Program Memory Type:: FLASH

EEPROM Size:: -

RAM Size:: 1K 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:

ST72F321BK6T6TR FAQ

1.How can I place an order for ST72F321BK6T6TR through Aetrix?

Please submit a Request for Quotation (RFQ) for ST72F321BK6T6TR 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 ST72F321BK6T6TR reliable?

The price and inventory of ST72F321BK6T6TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ST72F321BK6T6TR is usually 5 days.

3.What payment methods are accepted for ST72F321BK6T6TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ST72F321BK6T6TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ST72F321BK6T6TR?

ST72F321BK6T6TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ST72F321BK6T6TR 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 ST72F321BK6T6TR?

For technical support, including ST72F321BK6T6TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ST72F321BK6T6TR requirements.

6.How does Aetrix verify that ST72F321BK6T6TR is sourced from the original manufacturer or authorized distributors?

All ST72F321BK6T6TR 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 ST72F321BK6T6TR meets industry standards.

7.What is the process for return or replacement of ST72F321BK6T6TR?

All ST72F321BK6T6TR units undergo pre-shipment inspection (PSI). If there is an issue with ST72F321BK6T6TR, 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 ST72F321BK6T6TR part is unused and in its original packaging.

Return procedure for ST72F321BK6T6TR:

1.Submit a request within 90 days.

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

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