PIC18F45K80-I/PT

The PIC18F45K80-I/PT is a member of Microchip’s PIC18F66K80 family of 8-bit microcontrollers featuring an integrated ECAN controller conforming to the CAN 2.0B active specification. The ’45’ variant provides 44 pins with 35 I/O, 32-KB Flash, 3648-B SRAM, and 1024-B EEPROM in a TQFP-44 package.

The ECAN module is the primary differentiator of this family. It supports CAN 2.0B active with standard (11-bit) and extended (29-bit) identifiers, up to 8 transmit and receive buffers, programmable bit rate up to 1 Mbit/s, and deviceNet filtering. This makes the PIC18F45K80 suitable for automotive, industrial, and building automation CAN bus applications without requiring an external CAN controller or transceiver (a CAN transceiver IC such as MCP2551 or TJA1050 is still needed for physical layer).

The nanoWatt XLP (eXtreme Low Power) technology delivers 20-nA sleep current with all peripherals off and RAM retained, 300-nA WDT operation, and 3.8-µA active mode at 1 MHz/1.8 V. The integrated 3.3-V LDO allows the device to operate from a 5-V rail while regulating the core to 3.3 V, reducing internal power consumption. The fast wake-up time (1 µs typical from sleep) enables duty-cycled battery operation.

The Charge Time Measurement Unit (CTMU) is a unique peripheral that measures capacitance changes with sub-picofarad resolution, enabling capacitive touch sensing, proximity detection, and precision time measurement without external components. Combined with the 12-bit ADC (11 channels) and two analog comparators, the PIC18F45K80 provides comprehensive analog capability for sensor interfaces.

The 64-MHz maximum clock (16 MIPS at 4:1 clock-to-MIPS ratio) provides adequate processing power for CAN message handling, sensor acquisition, and control loops. The 5 timers, 4 CCP modules, and 1 Enhanced CCP (with auto-shutdown and half/full-bridge PWM) support precision timing and motor control applications.

The PIC18F45K80 is recommended for automotive design (special ordering codes for automotive-grade versions). The ‘I’ temperature grade supports -40°C to +85°C, and the ‘/PT’ suffix denotes the TQFP-44 package in tray packaging.

**PIC18 CPU Core:** The PIC18 core uses a 16-bit instruction word with a 2-stage pipeline. Most instructions execute in a single cycle (4 clock periods at the instruction clock rate of FOSC/4). The 32-KB Flash stores up to 16,384 instructions. The 16-level hardware call/return stack supports nested interrupts and subroutines. A hardware multiply instruction completes in one cycle.

**ECAN Module:** The Enhanced CAN (ECAN) module implements the CAN 2.0B protocol. It includes a CAN protocol engine, message assembly/disassembly logic, and up to 8 configurable transmit/receive buffers. The module handles bit timing, CRC generation/checking, error management, and bit stuffing automatically. Software configures baud rate, filter/mask registers, and buffer priorities. The ECAN module operates independently of the CPU, allowing background CAN communication while the CPU executes application code.

**nanoWatt XLP Power Management:** The power management module provides multiple low-power modes: Run (CPU + peripherals active), Idle (CPU off, peripherals on), Sleep (CPU and peripherals off, RAM retained, WDT optional). The on-chip LDO regulates the core voltage to 3.3 V from a 1.8-V to 5.5-V supply. The ultra-low-power sleep mode (20 nA) is achieved by disabling all oscillators, BOR, and WDT while maintaining SRAM content through a dedicated retention path.

**CTMU (Charge Time Measurement Unit):** The CTMU generates a constant current source (0.55-550 µA programmable) that charges an external or internal capacitance. By measuring the time to reach a voltage threshold (via ADC or comparator), the capacitance value is determined. For touch sensing, finger proximity increases the sensor capacitance, which the CTMU detects as a longer charge time.