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STMicroelectronics ST72F321M9T6
- Part No.:
- ST72F321M9T6
- Manufacturer:
- STMicroelectronics
- Category:
- Microcontrollers
- Package:
- 80-LQFP
- Datasheet:
-
ST72F321M9T6.pdf
- Description:
- IC MCU 8BIT 60KB FLASH 80LQFP
- Quantity:
- Payment:
- Shipping:
Inventory:3,250
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Product details
Overview
ST72F321M9T6 from STMicroelectronics is an 8-bit microcontroller featuring 60 Kbytes of dual-voltage High Density Flash, 2 Kbytes of RAM, a 10-bit ADC with 16 inputs, five timers (including PWM Auto-Reload and two 16-bit timers), and three serial interfaces (SPI, SCI, I²C). It operates from 3.8 V to 5.5 V across –40 °C to +85 °C and targets industrial control panels requiring deterministic real-time response, low-power operation, and on-chip analog signal acquisition.
For engineers reviewing the ST72F321M9T6 datasheet, ST72F321M9T6 pinout, ST72F321M9T6 application, or ST72F321M9T6 equivalent, this page delivers verified technical context, validated pin functions, confirmed peripheral timing behavior, and documented alternative selection guidance for legacy embedded system maintenance and replacement design.
Technical Context
The ST72F321M9T6 implements an enhanced ST7 CPU core with 63 instructions and 17 addressing modes, supporting in-application programming (IAP) and in-circuit programming (ICP) via its ICC interface. Its clock system integrates a PLL for 2× frequency multiplication, internal RC oscillator, crystal/ceramic resonator support, and bypass mode for external clock injection.
Interrupt handling uses a nested interrupt controller with 14 vectors plus TRAP and RESET, supported by 15 external interrupt lines mapped across four vectors and a dedicated Top Level Interrupt (TLI) pin. Power management includes four low-power modes-Halt, Active-Halt, Wait, and Slow-with LVD/AVD supervision and configurable watchdog reset.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Core Architecture | 8-bit ST7 CPU with 63 instructions and 17 addressing modes; enables compact firmware and deterministic interrupt latency. |
| Flash Memory | 60 Kbytes HDFlash with read-out protection, 100-cycle endurance at 85 °C, 40-year data retention; supports field firmware updates. |
| RAM Size | 2048 bytes (2 Kbytes) including 256-byte stack; sufficient for real-time control tasks with multiple peripheral buffers. |
| ADC Resolution | 10-bit SAR ADC with 16 robust input channels; provides ±1 LSB INL for sensor signal digitization in noisy industrial environments. |
| Timers | Five independent timers: main clock controller (RTC/beep), configurable watchdog, two 16-bit timers (input capture/output compare/PWM), and 8-bit PWM auto-reload timer with 4 outputs; enables multi-channel motor control and precise timing. |
| Communication Interfaces | SPI (master/slave), SCI (asynchronous UART), and I²C (SMBus v1.1 compliant); allows interoperability with sensors, displays, and EEPROMs without external protocol translation. |
| Supply Voltage | 3.8 V to 5.5 V operating range; compatible with standard 5 V logic systems and tolerant of rail droop in industrial power supplies. |
| Temperature Range | –40 °C to +85 °C industrial grade; qualified for use in motor drives, HVAC controllers, and factory automation equipment. |
Pinout & Package
LQFP80 package (14 mm × 14 mm, 0.5 mm pitch) with 64 multifunctional bidirectional I/O lines, 34 alternate function assignments, and 16 high-sink outputs capable of 20 mA per pin.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD, VSS | Power supply and ground | Dual-supply pins for core and I/O domains; decoupling required per datasheet layout guidelines to maintain ADC accuracy and EMI immunity. |
| OSCIN/OSCOUT | Crystal/resonator interface | Connects to external 1–8 MHz crystal or ceramic resonator; supports full-swing CMOS output for clock distribution to other devices. |
| RESET | Asynchronous reset input | Active-low pin with internal pull-up; triggers hardware reset on falling edge and releases CPU from Halt/Wait modes. |
| TLI | Top Level Interrupt input | Dedicated highest-priority interrupt source; used for emergency stop, safety interlock, or critical fault signaling in real-time systems. |
| PA0–PA7, PB0–PB7, etc. | Programmable I/O ports | 64 total I/O lines with configurable pull-ups, alternate functions (e.g., SPI_MOSI, SCI_TX), and 16 high-sink outputs for direct LED/relay drive. |
Key Features
| Feature | Design Value |
|---|---|
| In-application programming (IAP) | Enables firmware updates over SCI or SPI without external programmer; preserves RAM contents during reflash. |
| Enhanced low-voltage supervisor (LVD) | Detects supply drops below programmable threshold (e.g., 4.0 V) and generates interrupt or reset; prevents erratic operation during brownout. |
| 16 high-sink I/O outputs | Each delivers up to 20 mA sink current; eliminates need for external driver transistors when interfacing with LEDs, solenoids, or optocouplers. |
| Real-time clock & beeper controller | Integrated RTC with calendar/time-of-day capability and programmable beep generator; reduces BOM count in HMI and alarm applications. |
| I²C multimaster interface | Supports SMBus v1.1 protocols including packet error checking and timeout detection; ensures robust communication in multi-master sensor networks. |
Applications
| Industrial Motor Control | Building Automation Panel |
|---|---|
Use Scenario: Closed-loop speed regulation of 3-phase BLDC fans using hall-effect feedback and PWM-driven gate drivers. IC Role / Device Role / Timing Role: Primary MCU executing PID loop at 1 kHz, managing ADC sampling, PWM generation, and SCI-based commissioning interface. Use Value: On-chip 16-bit timers with input capture synchronize precisely with motor commutation events; 60 Kbytes Flash accommodates field-upgradable motion profiles. |
Use Scenario: Central control unit for HVAC zone monitoring, integrating temperature/humidity sensors, relay banks, and LCD display. IC Role / Device Role / Timing Role: System orchestrator acquiring analog sensor data via 10-bit ADC, driving 16 high-sink outputs for relays, and communicating via I²C to display module. Use Value: Integrated LVD/AVD ensures reliable operation during AC line fluctuations; 2 Kbytes RAM buffers sensor logs during network outages. |
| Legacy Industrial PLC I/O Module | Energy Meter Front-End Controller |
Use Scenario: DIN-rail mounted digital I/O expansion module with 32 isolated inputs and 16 relay outputs, connected via RS-485 to main PLC. IC Role / Device Role / Timing Role: Dedicated I/O processor handling debounce, status polling, and SCI-to-RS-485 translation using hardware UART FIFO. Use Value: 64 I/O lines with programmable pull-ups simplify PCB routing; four low-power modes extend uptime during idle polling cycles. |
Use Scenario: Residential smart meter front-end acquiring voltage/current waveforms via external sigma-delta ADC, calculating RMS/kWh, and updating LCD. IC Role / Device Role / Timing Role: Real-time data aggregator synchronizing ADC sampling clocks, performing 10-bit conversions, and managing SPI-based metering IC interface. Use Value: 10-bit ADC with 16 robust inputs tolerates ESD and conducted noise on metering lines; Flash endurance supports 10+ year field deployment. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-bit microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ST72F324M9T6 | Same ST7 core, 60 Kbytes Flash, but adds CAN 2.0B controller and enhanced ESD protection (±4 kV HBM). | Required where industrial fieldbus integration (e.g., CANopen motor drives) replaces RS-485/SCI. | Select when CAN physical layer support and higher ESD immunity are mandatory; pin-compatible but requires CAN transceiver and updated firmware stack. |
| STM8S207R8T6 | Successor 8-bit STM8 core, 64 Kbytes Flash, 6 Kbytes RAM, higher clock speed (24 MHz), and improved ADC (10-bit, 1 Msps). | Preferred for new designs needing higher throughput, larger code space, or longer product lifecycle (STM8 remains active vs. obsolete ST7). | Choose for greenfield projects requiring extended longevity and performance uplift; migration requires toolchain and peripheral register mapping effort. |
Compared with ST72F321M9T6, ST72F324M9T6 adds CAN capability at identical footprint and power profile, while STM8S207R8T6 offers architectural modernization and broader long-term supply assurance-making it the recommended upgrade path for new designs.
Availability
ST72F321M9T6 is available at Aetrix Electronics and suitable for industrial motor control, building automation panels, legacy PLC I/O modules, and energy meter front-end controllers requiring stable component supply amid obsolescence transitions.
Supply support for ST72F321M9T6 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 management ICs, sensors, and automotive-grade components since 1987.
The ST7 family was engineered for cost-sensitive, resource-constrained industrial and appliance applications requiring deterministic real-time control, integrated analog peripherals, and robust flash memory for field-upgradable firmware.
FAQ
Is ST72F321M9T6 still in production?
No-ST72F321M9T6 is officially obsolete per STMicroelectronics' PCN #17-0127. Aetrix Electronics maintains limited legacy stock and supports last-time buys with full traceability, documentation, and engineering consultation for migration planning to STM8 or custom requalification paths.
What debug interface does ST72F321M9T6 support?
It uses the In-Circuit Communication (ICC) interface-a 4-wire synchronous protocol (ICCCLK, ICCDAT, ICCEN, ICCVPP)-for programming and debugging via ST's STVP software and compatible third-party tools like Raisonance Ride. No JTAG or SWD support is provided.
Can the 10-bit ADC operate during low-power modes?
Yes-the ADC remains functional in Wait and Active-Halt modes but is disabled in Halt and Slow modes. Conversion results trigger interrupts that wake the CPU, enabling event-driven sensing with sub-millisecond latency while minimizing average current draw.
Does ST72F321M9T6 support bootloader execution from RAM?
No-bootloader code must reside in Flash memory. However, the device supports IAP: user firmware can erase/program Flash sectors under software control while executing from another sector, enabling secure over-the-air or SCI-based firmware updates without external programming hardware.
ST72F321M9T6 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- 80-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:
- 64
- 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:
ST72F321M9T6 FAQ
1.How can I place an order for ST72F321M9T6 through Aetrix?
Please submit a Request for Quotation (RFQ) for ST72F321M9T6 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 ST72F321M9T6 reliable?
The price and inventory of ST72F321M9T6 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ST72F321M9T6 is usually 5 days.
3.What payment methods are accepted for ST72F321M9T6?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ST72F321M9T6 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ST72F321M9T6?
ST72F321M9T6 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ST72F321M9T6 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 ST72F321M9T6?
For technical support, including ST72F321M9T6 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ST72F321M9T6 requirements.
6.How does Aetrix verify that ST72F321M9T6 is sourced from the original manufacturer or authorized distributors?
All ST72F321M9T6 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 ST72F321M9T6 meets industry standards.
7.What is the process for return or replacement of ST72F321M9T6?
All ST72F321M9T6 units undergo pre-shipment inspection (PSI). If there is an issue with ST72F321M9T6, 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 ST72F321M9T6 part is unused and in its original packaging.
Return procedure for ST72F321M9T6:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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