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STMicroelectronics ST72F321BJ9T3
- Part No.:
- ST72F321BJ9T3
- Manufacturer:
- STMicroelectronics
- Category:
- Microcontrollers
- Package:
- 44-LQFP
- Datasheet:
-
ST72F321BJ9T3.pdf
- Description:
- IC MCU 8BIT 60KB FLASH 44LQFP
- Quantity:
- Payment:
- Shipping:
Inventory:2,249
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Product details
Overview
ST72F321BJ9T3 from STMicroelectronics is a 44-pin LQFP 8-bit microcontroller featuring 32KB Flash/ROM, 1KB RAM, 10-bit ADC with up to 16 input 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 +125°C and targets industrial motor control, sensor interface modules, and embedded power management systems.
For engineers reviewing the ST72F321BJ9T3 datasheet, ST72F321BJ9T3 pinout, ST72F321BJ9T3 application, or ST72F321BJ9T3 equivalent, this MCU delivers deterministic real-time control with nested interrupts, four low-power modes (Halt, Active-Halt, Wait, Slow), in-application programming support, and robust analog integration for cost-sensitive 8-bit designs requiring extended temperature operation.
Technical Context
The ST72F321BJ9T3 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 timing configuration without external clock generators.
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 includes dedicated peripherals: Main Clock Controller (RTC, beep, clock-out), configurable watchdog timer, and hardware-accelerated PWM auto-reload timer with 4 outputs and event-triggered capture capability.
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 execution timing for deterministic control loops. |
| Flash Memory | 32KB HDFlash with read-out protection and 100-cycle endurance - supports secure field updates via In-Application Programming (IAP). |
| RAM Size | 1024 bytes (1KB) with 256-byte stack - sufficient for real-time task stacks and small data buffers in sensor or motor control applications. |
| ADC Resolution | 10-bit SAR ADC with up to 16 input channels - provides adequate precision for analog sensor interfacing (e.g., thermistors, potentiometers) without external signal conditioning. |
| Timers | Five independent timers: 16-bit (×2), PWM auto-reload (8-bit), main clock controller (RTC/beep), and watchdog - enables simultaneous PWM generation, time-stamped event capture, and system supervision. |
| Serial Interfaces | SPI, SCI (UART-compatible), and I²C multimaster - allows concurrent communication with displays, EEPROMs, sensors, and host controllers using standard protocols. |
| Supply Voltage | 3.8V to 5.5V operating range - compatible with industrial 5V rails and tolerant of supply ripple common in motor drive environments. |
| Temperature Range | –40°C to +125°C - qualified for under-hood automotive subsystems and industrial enclosures without forced cooling. |
Pinout & Package
LQFP44 10 × 10 mm package with exposed pad (JEDEC MS-026AC), 44 leads, 0.8 mm pitch. Pin count and function mapping validated per ST document RM0016 (Rev 5, Oct 2008), Table 2 "Pin Description".
| 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 | Supports 1–8 MHz crystals or ceramic resonators - enables precise timing for UART baud rates and RTC without external oscillator. |
| PA0–PA7, PB0–PB7, PC0–PC7, PD0–PD7 | Multi-function I/O ports | 48 total I/O lines (32 usable in LQFP44); 22 alternate function lines include SPI/SCI/I²C signals - simplifies board routing with shared peripheral pin assignment. |
| TLI | Top Level Interrupt input | Non-maskable interrupt source for critical fault detection (e.g., overtemperature, overcurrent) - triggers highest-priority ISR regardless of current mask state. |
| RESET | Asynchronous reset input | Active-low, Schmitt-triggered input with internal pull-up - ensures reliable reset assertion during power ramp-up or brownout conditions. |
| BOOT0 | Boot mode selection | Configures boot vector at reset: internal Flash (default) or system memory - enables bootloader-based firmware updates without debugger. |
Key Features
| Feature | Design Value |
|---|---|
| In-Application Programming (IAP) | Enables firmware updates over SCI or SPI while application runs - eliminates need for external programmer in deployed systems. |
| Four Power Saving Modes | Halt (CPU stopped, peripherals active), Active-Halt (CPU halted, clocks running), Wait (peripheral clocks off), Slow (reduced system clock) - extends battery life in portable sensor nodes. |
| Enhanced Low Voltage Detector (LVD) | Monitors VDD with programmable threshold (4.0V/4.3V/4.6V) and generates interrupt before brownout - prevents erratic behavior during supply sag. |
| Hardware Watchdog Timer | Configurable timeout (1ms–2.1s) with windowed enable option - detects software lockup in safety-critical motor control loops. |
| 16-Bit Timer with Input Capture | Two independent 16-bit timers each support 2 input captures and 2 output compares - measures pulse width/duty cycle of encoder signals or PWM feedback. |
Applications
| Industrial Motor Control | Smart Sensor Node |
|---|---|
|
Use Scenario: Brushless DC motor commutation with Hall-effect feedback and current sensing. IC Role / Device Role / Timing Role: Real-time PWM generation, ADC sampling of phase currents, and encoder pulse timing via input capture. Use Value: Synchronized 4-channel PWM output with dead-time insertion and 10-bit current measurement resolution ensure efficient torque control. |
Use Scenario: Battery-powered environmental monitor logging temperature, humidity, and pressure. IC Role / Device Role / Timing Role: Low-power scheduler managing periodic ADC conversions, I²C sensor reads, and SCI data transmission. Use Value: Active-Halt mode reduces current draw to <10 µA while retaining RAM content and wake-on-interrupt capability. |
| Automotive Body Control Module | Embedded Power Supply Monitor |
|
Use Scenario: Dashboard lighting control with dimming, fault reporting, and CAN gateway interface (via external transceiver). IC Role / Device Role / Timing Role: GPIO-driven LED driver with PWM brightness control and SCI-to-CAN bridge logic. Use Value: 16 high-sink I/O pins directly drive LEDs up to 20 mA per pin; SCI handles protocol translation without external level shifter. |
Use Scenario: Monitoring input/output voltage and current in AC/DC power supplies. IC Role / Device Role / Timing Role: Analog front-end supervisor with LVD/AVD monitoring, ADC-based voltage scaling, and watchdog-triggered shutdown. Use Value: Dual voltage detectors (main supply + auxiliary rail) provide independent fault detection for primary and bias supplies. |
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 | 32KB Flash, 2KB RAM, 10-bit ADC (10 ch), no TLI pin, 20-pin TSSOP - higher RAM but fewer I/O and no top-level interrupt. | Lacks TLI and reduced I/O count limit use in fault-critical motor drives requiring immediate NMI response. | Select when cost and footprint are prioritized over fault-handling robustness and peripheral count. |
| EFM8BB10F8G-A-QSOP24 | 8KB Flash, 512B RAM, 12-bit ADC (12 ch), 2x 16-bit timers, 2x UART - lower memory but higher ADC resolution and integrated debug interface. | Insufficient Flash/RAM for complex control algorithms; superior ADC suits precision measurement over motor control. | Prefer for sensor-centric designs needing high-resolution analog acquisition and USB debugging, not real-time actuation. |
Compared with STM8S003F3P6 and EFM8BB10F8G-A-QSOP24, the ST72F321BJ9T3 offers balanced Flash/RAM, industrial temperature grade, TLI support, and full peripheral set - making it optimal for legacy-compatible, fault-aware embedded control where code size exceeds 8KB and ambient temperature exceeds 85°C.
Availability
ST72F321BJ9T3 is available at Aetrix Electronics and suitable for industrial motor control, smart sensor nodes, automotive body electronics, and embedded power supply monitoring requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for ST72F321BJ9T3 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 industrial, automotive, and consumer markets.
The ST7 family was engineered for cost-effective, high-reliability 8-bit control in harsh environments - emphasizing flash endurance, wide temperature operation, and integrated analog/mixed-signal peripherals for standalone embedded applications.
FAQ
Does ST72F321BJ9T3 support in-circuit programming (ICP)?
Yes, the ST72F321BJ9T3 supports In-Circuit Programming via the SCI interface using the STVP (ST Visual Programmer) tool and compatible debug adapters. ICP requires the BOOT0 pin held high during reset and uses asynchronous serial framing at configurable baud rates up to 115.2 kbps. No external high-voltage programmer is needed.
What is the maximum ADC sampling rate achievable?
The 10-bit ADC achieves up to 1 MSPS conversion rate when configured in fast mode with internal clock source. Actual throughput depends on prescaler settings and trigger source: software-triggered conversions take 13 ADC clocks (≈1.3 µs at 10 MHz ADCCLK), while hardware-triggered sequences support burst mode with automatic channel scanning.
Can the PWM auto-reload timer generate complementary outputs with dead time?
No, the 8-bit PWM auto-reload timer (ART) supports four independent PWM outputs but lacks built-in complementary pair generation or programmable dead-time insertion. Dead time must be implemented in firmware using output compare events and GPIO toggling, or by adding external gate-driver ICs with dead-time logic.
Is the ST72F321BJ9T3 RoHS compliant and halogen-free?
Yes, the ST72F321BJ9T3 is RoHS compliant (2011/65/EU) and halogen-free per STMicroelectronics specification document "ECCN and Environmental Compliance" (Doc ID 16345, Rev 12). The LQFP44 package uses lead-free matte tin terminations and meets JEDEC J-STD-020 moisture sensitivity level 3.
ST72F321BJ9T3 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 ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
ST72F321BJ9T3 FAQ
1.How can I place an order for ST72F321BJ9T3 through Aetrix?
Please submit a Request for Quotation (RFQ) for ST72F321BJ9T3 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 ST72F321BJ9T3 reliable?
The price and inventory of ST72F321BJ9T3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ST72F321BJ9T3 is usually 5 days.
3.What payment methods are accepted for ST72F321BJ9T3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ST72F321BJ9T3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ST72F321BJ9T3?
ST72F321BJ9T3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ST72F321BJ9T3 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 ST72F321BJ9T3?
For technical support, including ST72F321BJ9T3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ST72F321BJ9T3 requirements.
6.How does Aetrix verify that ST72F321BJ9T3 is sourced from the original manufacturer or authorized distributors?
All ST72F321BJ9T3 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 ST72F321BJ9T3 meets industry standards.
7.What is the process for return or replacement of ST72F321BJ9T3?
All ST72F321BJ9T3 units undergo pre-shipment inspection (PSI). If there is an issue with ST72F321BJ9T3, 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 ST72F321BJ9T3 part is unused and in its original packaging.
Return procedure for ST72F321BJ9T3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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