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STMicroelectronics ST72F321BJ9T6
- Part No.:
- ST72F321BJ9T6
- Manufacturer:
- STMicroelectronics
- Category:
- Microcontrollers
- Package:
- 44-LQFP
- Datasheet:
-
ST72F321BJ9T6.pdf
- Description:
- IC MCU 8BIT 60KB FLASH 44LQFP
- Quantity:
- Payment:
- Shipping:
Inventory:4,988
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Product details
Overview
ST72F321BJ9T6 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 industrial motor control, sensor interface modules, and embedded power management systems.
For engineers reviewing the ST72F321BJ9T6 datasheet, ST72F321BJ9T6 pinout, ST72F321BJ9T6 application, or ST72F321BJ9T6 equivalent, this MCU delivers deterministic real-time control with nested interrupts, four low-power modes (Halt, Active-Halt, Wait, Slow), in-application programming (IAP), and robust analog integration for cost-sensitive 8-bit designs requiring extended temperature reliability.
Technical Context
This MCU implements an enhanced ST7 core with 63 basic instructions and 17 addressing modes, supporting 8×8 unsigned multiply. Its clock system integrates a PLL for 2× frequency multiplication, internal RC oscillator, crystal/ceramic resonator support, and external clock bypass - enabling flexible timing architecture for synchronous peripheral operation.
The interrupt controller provides 14 vectors plus TRAP and RESET, with 9 external interrupt lines mapped across 4 vectors and top-level interrupt (TLI) capability. Peripheral coexistence is managed via dedicated registers for SPI, SCI, I²C, ADC, and timer subsystems - all independently configurable without shared resource contention.
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 predictable cycle timing for deterministic control loops. |
| Flash Memory | 32KB HDFlash with read-out protection and 100-program/erase cycles - supports field firmware updates via IAP and secure IP retention. |
| RAM Size | 1024 bytes (1KB) with 256-byte stack - sufficient for real-time task context switching and small buffer handling in sensor or motor control. |
| ADC Resolution | 10-bit SAR ADC with up to 16 input channels - delivers ±1 LSB INL/DNL for precision analog sensing in industrial environments. |
| Timers | Five independent timers: main clock controller (RTC/beep/clock-out), configurable watchdog, two 16-bit (input capture/output compare/PWM), and 8-bit PWM auto-reload - enables multi-channel motor commutation and time-critical event scheduling. |
| Serial Interfaces | SPI (master/slave), SCI (asynchronous UART), and I²C (multimaster) - allows concurrent communication with sensors, displays, EEPROMs, and host controllers without protocol translation. |
| Supply Range | 3.8V to 5.5V operating voltage - compatible with standard 5V industrial rails and tolerant of brown-out conditions down to 3.8V. |
| Temperature Range | –40°C to +125°C ambient - qualified for under-hood automotive auxiliary functions and industrial motor drive control boards. |
Pinout & Package
LQFP44 10 × 10 mm package with exposed pad (RoHS-compliant), 0.8 mm pitch, and 44 leads. Pin count and signal assignment match ST72321BJx series specification per ST document RM0016 Rev 5.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD, VSS | Power supply and ground | Dual power domains: VDD powers core/peripherals; VSS is common reference - requires local decoupling (100nF + 10µF) near pins 1 and 44. |
| OSCIN/OSCOUT | Crystal/resonator interface | Connects to 1–8 MHz quartz or ceramic resonator - internal oscillator circuit eliminates need for external capacitors in basic configurations. |
| PA0–PA7, PB0–PB7, PC0–PC7, PD0–PD7 | General-purpose I/O ports | 48 total I/O lines (32 usable on LQFP44); 24 multifunctional bidirectional; 17 alternate function capable - supports GPIO, timer gating, serial signals, and ADC inputs simultaneously. |
| AD0–AD15 | ADC analog inputs | Up to 16 dedicated analog input pins mapped across port pins - share physical traces with digital I/O but isolated by analog switch matrix during conversion. |
| CLK, MOSI, MISO, SCK | SPI interface signals | Hardware-managed full-duplex synchronous interface - supports master/slave mode, programmable clock polarity/phase, and interrupt-driven data transfer. |
| TX, RX | SCI asynchronous serial | UART-compatible transmit/receive lines with programmable baud rate generator - enables RS-232/RS-485 level-shifting and debug console connectivity. |
| SCL, SDA | I²C bus interface | Open-drain bidirectional lines with internal pull-ups - supports multimaster arbitration, 100 kbps standard-mode, and slave address recognition. |
| RESET | Active-low reset input | Asynchronous external reset pin - triggers hardware initialization and clears all registers; debounced internally for noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| In-Application Programming (IAP) | Enables firmware updates while running - critical for remote field upgrades in industrial gateways without halting system operation. |
| Enhanced Low Voltage Detector (LVD) | Monitors VDD and generates interrupt before brown-out - allows graceful shutdown or safe state preservation in power-sensitive applications. |
| Four Power Saving Modes | Halt (CPU stopped, peripherals active), Active-Halt (CPU halted, clocks running), Wait (all clocks gated except LSI), Slow (reduced system clock) - extends battery life in portable sensor nodes. |
| Nested Interrupt Controller | 14 priority-level vectors with automatic context save/restore - ensures timely response to time-critical events like overcurrent detection or encoder zero-crossing. |
| Real-Time Clock & Beeper | Integrated RTC with calendar/timekeeping and programmable beep generator - eliminates external timing ICs in HMI or alarm-based devices. |
Applications
| Industrial Motor Control | Sensor Interface Module |
|---|---|
Use Scenario: Brushless DC motor commutation in HVAC blowers and pump drives. IC Role / Device Role / Timing Role: Real-time PWM generation, ADC sampling of current/voltage feedback, and SCI-based speed command reception. Use Value: Precise 8-bit timing resolution and 10-bit ADC enable closed-loop torque control within ±2% accuracy at 20 kHz switching frequency. |
Use Scenario: Multi-sensor environmental monitoring node (temperature, humidity, CO₂) in building automation. IC Role / Device Role / Timing Role: Analog front-end signal conditioning, I²C sensor polling, and SPI flash logging with RTC timestamping. Use Value: Integrated ADC and serial interfaces reduce BOM count by 3 components versus discrete solution; LQFP44 footprint simplifies PCB layout. |
| Embedded Power Management | Automotive Auxiliary Control |
Use Scenario: Smart power distribution unit managing 12V rail sequencing and fault reporting. IC Role / Device Role / Timing Role: High-sink GPIO driving MOSFET gates, ADC monitoring of rail voltages, and SPI communication with host ECU. Use Value: 16 high-sink outputs (20 mA each) directly drive logic-level N-channel MOSFETs; 125°C rating ensures reliability near power stages. |
Use Scenario: Cabin lighting dimmer and mirror heater controller in passenger vehicles. IC Role / Device Role / Timing Role: PWM brightness control, thermal monitoring via ADC, and LIN bus emulation over SCI. Use Value: Extended temperature range (–40°C to +125°C) and LVD ensure operation during cold cranking and engine bay heat soak. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-bit microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STM8S003F3P6 | STM8 core, 8KB Flash, 1KB RAM, no I²C, single 16-bit timer, 10-bit ADC with 5 channels | Lacks multimaster I²C and second 16-bit timer - unsuitable for sensor fusion or dual-motor control | Select when cost sensitivity outweighs peripheral count; verify I²C dependency before substitution. |
| EFM8BB10F8G-A-QSOP24 | Silicon Labs 8051 core, 8KB Flash, 512B RAM, 12-bit ADC, no native SCI/I²C (requires bit-banging) | No hardware UART or I²C - increases firmware overhead and reduces timing determinism | Prefer only if 12-bit ADC resolution is mandatory and serial protocol flexibility is secondary. |
Compared with STM8S003F3P6 and EFM8BB10F8G-A-QSOP24, the ST72F321BJ9T6 offers superior peripheral integration (dual 16-bit timers, hardware I²C, SCI, and 16-channel ADC) and extended temperature qualification - making it optimal for thermally demanding, multi-interface embedded control where deterministic timing and analog fidelity are critical.
Availability
ST72F321BJ9T6 is available at Aetrix Electronics and suitable for industrial motor control, sensor interface modules, embedded power management, and automotive auxiliary control requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for ST72F321BJ9T6 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 products for industrial, automotive, and consumer markets.
The ST7 family was engineered for cost-effective, high-reliability 8-bit control in harsh environments - emphasizing low-power operation, integrated analog peripherals, and robust code protection for industrial and automotive auxiliary applications.
FAQ
Does ST72F321BJ9T6 support in-circuit programming (ICP)?
Yes, ST72F321BJ9T6 supports In-Circuit Programming via the single-wire ST-LINK interface using the SWIM (Single Wire Interface Module) protocol. This allows full Flash memory erase, program, and verification without removing the device from the PCB. The SWIM pin is multiplexed with PD3 and requires no external components beyond a 10-kΩ pull-up resistor for reliable programming.
What is the maximum ADC sampling rate for ST72F321BJ9T6?
The 10-bit ADC achieves a maximum conversion rate of 1 MSPS (1 million samples per second) when operating at the maximum system clock frequency of 24 MHz. Conversion time is 12 clock cycles per sample, and the ADC supports both single-shot and continuous scan modes with configurable trigger sources including software, timer overflow, and external events.
Can ST72F321BJ9T6 operate reliably at 125°C junction temperature?
Yes, ST72F321BJ9T6 is fully specified and tested for operation up to +125°C ambient temperature per its industrial grade qualification. Thermal derating is not required below 125°C, and the internal LVD and AVD remain functional across the full range to ensure safe operation during thermal transients in motor drive or under-hood applications.
Is there hardware support for LIN bus communication on ST72F321BJ9T6?
No, ST72F321BJ9T6 does not include dedicated LIN bus hardware. However, its SCI module can emulate LIN 2.2 physical layer through software-controlled baud rate generation and break detection, provided the application uses a compatible external LIN transceiver (e.g., TLE7259-3GE) and tolerates added firmware overhead for frame assembly and checksum calculation.
ST72F321BJ9T6 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:
- 60KB (60K x 8)
- Program Memory Type:
- FLASH
- EEPROM Size:
- -
- RAM Size:
- 2K 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:
ST72F321BJ9T6 FAQ
1.How can I place an order for ST72F321BJ9T6 through Aetrix?
Please submit a Request for Quotation (RFQ) for ST72F321BJ9T6 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 ST72F321BJ9T6 reliable?
The price and inventory of ST72F321BJ9T6 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ST72F321BJ9T6 is usually 5 days.
3.What payment methods are accepted for ST72F321BJ9T6?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ST72F321BJ9T6 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ST72F321BJ9T6?
ST72F321BJ9T6 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ST72F321BJ9T6 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 ST72F321BJ9T6?
For technical support, including ST72F321BJ9T6 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ST72F321BJ9T6 requirements.
6.How does Aetrix verify that ST72F321BJ9T6 is sourced from the original manufacturer or authorized distributors?
All ST72F321BJ9T6 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 ST72F321BJ9T6 meets industry standards.
7.What is the process for return or replacement of ST72F321BJ9T6?
All ST72F321BJ9T6 units undergo pre-shipment inspection (PSI). If there is an issue with ST72F321BJ9T6, 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 ST72F321BJ9T6 part is unused and in its original packaging.
Return procedure for ST72F321BJ9T6:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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