STMicroelectronics ST72F321R9TCTR

Overview

ST72F321R9TCTR from STMicroelectronics is an 8-bit microcontroller featuring 60KB on-chip HDFlash program memory, 2KB RAM, 10-bit ADC with up to 16 input channels, five timers (including PWM auto-reload and dual 16-bit timers), 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, industrial sensor nodes, and appliance motor control systems.

For engineers reviewing the ST72F321R9TCTR datasheet, ST72F321R9TCTR pinout, ST72F321R9TCTR application, or ST72F321R9TCTR equivalent, this MCU delivers deterministic real-time response via nested interrupt controller (14 vectors + TRAP/RESET), configurable watchdog, PLL-based clock multiplication, and four low-power modes - critical for battery-backed or thermally constrained embedded designs.

Technical Context

The ST72F321R9TCTR implements the ST7 CPU core with 63 basic instructions and 17 addressing modes, supporting in-application programming (IAP) and in-circuit programming (ICP) for field firmware updates. Its clock system integrates crystal/resonator oscillators, internal RC oscillator, external clock bypass, and a 2× PLL for precise frequency scaling.

Peripheral integration includes a main clock controller with real-time base, beep generator, and clock-out capability; a 10-bit ADC with programmable sampling time and scan mode; and dual 16-bit timers offering input capture, output compare, PWM, and pulse generation - all synchronized to the same clock domain for deterministic timing.

Key Specifications

Pinout & Package

LQFP64 14 × 14 mm package with exposed thermal pad (RoHS-compliant, Pb-free).

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM8S207R8T6 and MC9S08DZ60CLL, the ST72F321R9TCTR offers unique TLI interrupt prioritization and optimized peripheral set for cost-sensitive, thermally demanding control tasks - making it especially valuable where deterministic fault response and 125°C operation are non-negotiable.

Availability

ST72F321R9TCTR is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor nodes, home appliance motor control, and smart meter interface modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ST72F321R9TCTR 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-effective, robust 8-bit control in harsh environments - emphasizing flash endurance, wide temperature operation, and integrated analog/mixed-signal peripherals for standalone embedded applications.

FAQ

What is the maximum operating frequency of the ST72F321R9TCTR?

The ST72F321R9TCTR achieves a maximum CPU frequency of 16 MHz using its internal PLL (2× multiplication of an 8 MHz crystal input). With external clock sources or RC oscillators, the core runs up to 8 MHz without PLL activation. All timing specifications in the datasheet assume operation within these limits and the specified voltage/temperature range.

Does the ST72F321R9TCTR support hardware debug interfaces?

No, the ST72F321R9TCTR does not include SWD, JTAG, or BDM debug interfaces. Development relies on ST's proprietary STVP (ST Visual Programmer) and ST-LINK-compatible tools via the SCI or SPI bootloader, or through in-circuit programming using the dedicated ICP pins (PC0–PC3, PD0–PD1) as defined in section 4.5 of the reference manual.

How many I/O pins support high-sink capability, and what is the rated current?

16 I/O pins (PA0–PA7, PB0–PB7, PC0–PC1, PD0–PD1, PE0–PE1) support high-sink operation at 20 mA per pin, with a total package sink limit of 120 mA. This capability enables direct driving of LEDs, small relays, or optocouplers without external transistor buffers - verified under 5.5V VDD and 25°C ambient conditions.

Is the ST72F321R9TCTR pin-compatible with other ST72321 variants?

Yes, the ST72F321R9TCTR shares identical pinout and package (LQFP64 14×14 mm) with ST72321R7 and ST72321R6 variants. Differences lie solely in Flash size (60KB vs. 48KB vs. 32KB) and RAM allocation (2KB vs. 1.5KB vs. 1KB), allowing drop-in replacement in hardware designs where firmware size permits.