PIC32MX254F128D-I/PT - 72MHz 128KB Flash 32-bit MCU | Microchip

The Microchip Technology PIC32MX254F128D-I/PT is a 32-bit MIPS M4K microcontroller operating at up to 72MHz, integrating 128KB Flash and 32KB SRAM in a 44-pin TQFP (10x10 mm) package, with on-chip USB 2.0 full-speed, three analog comparators, CTMU, RTCC, and eXLP low-power peripherals. According to the Microchip PIC32MX1XX/2XX 28/36/44-pin family datasheet (DS60001168L), the part is qualified for industrial temperature range -40C to +85C and ships in tape-and-reel packaging. The 32KB SRAM is a notable feature among PIC32MX25x devices, supporting audio USB stores and graphics processing workloads.

A 32-bit microcontroller (MCU) is an integrated circuit that combines a CPU core, program memory (Flash), data memory (SRAM), and a rich mix of peripherals (USB, comparators, ADC, timers, communication interfaces) on a single silicon die. Within the taxonomy, PIC32MX254F128D belongs to the PIC32 family, which is itself a member of the MIPS M4K architecture class, positioning it as a mid-range 32-bit MCU targeted at USB-enabled embedded designs that need more memory than 8/16-bit parts can provide.

Key differentiating features include the MIPS32 M4K core with single-cycle hardware multiply/divide, dedicated USB 2.0 full-speed OTG peripheral, three on-chip analog comparators with programmable reference, a Charge Time Measurement Unit (CTMU) for capacitive touch and precise time measurement, and a Real-Time Clock Calendar (RTCC) module for date/time-keeping with backup battery support.

The architecture integrates a 5-channel DMA controller, 16-bit parallel master port for external memory or graphics, and audio/graphics interface logic. The eXLP (eXtreme Low Power) features include deep-sleep currents in the microampere territory, with multiple low-power modes that allow battery-powered applications to extend operational lifetime.

Typical applications include USB peripherals (HID, CDC, audio), audio playback devices, graphics-enabled HMIs with parallel LCDs, capacitive touch interfaces using CTMU, and battery-powered industrial sensors. The combination of 128KB Flash and 32KB RAM is sufficient for protocol stacks such as USB, USB HID class stacks, and open-source RTOS ports such as FreeRTOS.

When designing with this part, ensure the VDD/Vbat pin is properly decoupled with at least a 4.7uF bulk capacitor plus 0.1uF high-frequency bypass. The USB bus-powered variant must observe USB 2.0 inrush current requirements, and the trace impedance on the D+/D- pair should be 90 ohms differential.

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