80 MHz Cortex-M3 with USB OTG and CAN — field-service note
The LM3S5651-IBZ80-C5: Texas Instruments Stellaris ARM Cortex-M3S 5000 series 32-bit microcontroller. Runs at 80 MHz with 128 KB Flash and 32 KB SRAM. Peripherals include USB OTG, CANbus, I2C, SPI, UART, and a 16-channel 10-bit ADC. 108-ball BGA (10x10 mm), -40°C to 85°C.
80 MHz — what it means for the control loop
At 80 MHz, the Cortex-M3 executes single-cycle multiply and hardware divide, so a PID loop or Modbus packet handler can run without wait-state stalls from Flash prefetch. The 32 KB SRAM leaves room for a double-buffered USB frame or a CAN message queue alongside the stack.
Connectivity mix: USB OTG plus CAN
USB OTG means the MCU can act as either a device (sensor data logger) or a host (flash drive for firmware update) on the same port. CANbus connects directly to industrial actuator networks without an external transceiver — just a CAN PHY chip. The QEI and PWM peripherals let it drive a brushed DC motor or read an incremental encoder without bit-banging GPIO.
Obsolete — sourcing through independent channels
Texas Instruments has marked the LM3S5651-IBZ80-C5 as Obsolete. No last-time-buy window remains open through the factory. For BOM lines that require this exact order code, supply runs through surplus and broker channels. We source and quote to order against an RFQ; availability and current pricing are confirmed at quote time. No direct pin-compatible second source is recorded in TI's official cross-reference for this Stellaris part.