PIC18F242-I/SP - 8-bit 40MHz MCU 16KB Flash 28-SPDIP | Microchip
MPN: PIC18F242-I/SP ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.01 | $9.01 |
| 10 | $8.12 | $81.20 |
| 100 | $7.05 | $705.00 |
| 500 | $6.1 | $3,050.00 |
| 1,000 | $5.3 | $5,300.00 |
PIC18F242-I/SP Overview
An 8-bit microcontroller (MCU) is a single-chip computer with an 8-bit data path, ALU, registers, and on-chip program/data memory. It belongs to the hierarchy: MCU -> microcontroller -> embedded processor -> semiconductor. The PIC18F series is a high-performance enhanced family within Microchip's 8-bit portfolio, using a RISC-style architecture with only 77 single-word instructions, yet delivering up to 10 MIPS throughput at 40 MHz. The "F" suffix indicates Flash-based program memory allowing in-circuit reprogramming, and the "I" suffix denotes the industrial operating temperature range.
Key features of the PIC18F242 include five channels of 10-bit Analog-to-Digital (A/D) conversion, two Capture/Compare/PWM (CCP) modules, an enhanced USART for RS-232/RS-485, a Synchronous Serial Port configurable as SPI (3-wire) or I²C (2-wire), 23 I/O pins with high-current sink/source capability, self-programming support, an ICD (In-Circuit Debugger) interface, and nanoWatt technology for power-managed sleep modes. The 28-pin SPDIP package provides 0.300-inch row spacing for breadboard-friendly prototyping and field-replaceable designs.
Typical applications include industrial control and sensing nodes, appliance control boards, low-cost motor-control signal conditioning, smart sensor interfaces, RS-232/RS-485 field-bus nodes, and battery-powered instruments that benefit from nanoWatt sleep modes. The wide operating voltage and industrial temperature range also suit HVAC controls and automotive aftermarket modules.
When designing with the PIC18F242, ensure the MCLR reset circuit uses the recommended 10 kΩ pull-up with a 100 nF decoupling capacitor to ground. Place a 0.1 µF decoupling capacitor close to each VDD pin and use the ICD pins (RB6/RB7) for in-circuit debugging without removing the device from the board.
This page synthesizes verified distributor pricing, drop-in same-package alternatives such as the PIC18F252-I/SP and PIC18F242-E/SP, and practical design notes not collected in any single manufacturer document.
Drop-in alternatives for PIC18F242-I/SP — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with PIC18F242-I/SP (same form factor and footprint) — differing in Package, ADC, Mounting Type, Core Architecture, Operating Temperature Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F252-I/SP
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F242-E/SP
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F252-E/SP
✅ Drop-In✓ In Stock
$6.5 / Unit
View Datasheet →PIC18F2423-I/SP
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F242-I/SP Maximum Ratings & Electrical Characteristics
| Architecture | 8-bit PIC18 enhanced RISC |
| Instruction Set Width | 16-bit (77 single-word instructions) |
| Maximum CPU Speed | 40 MHz (10 MIPS) |
| Flash Program Memory | 16 KB (8K x 16) |
| SRAM Data Memory | 768 bytes |
| EEPROM | 256 bytes |
| Supply Voltage (VDD) | 4.2 V to 5.5 V |
| I/O Pins | 23 |
| A/D Converter | 10-bit, 5 channels |
| Capture/Compare/PWM (CCP) | 2 modules |
| Serial Interfaces | USART, SPI / I²C (SSP) |
| Timers | 4 (Timer0, Timer1, Timer2, Timer3) |
| Operating Temperature Range | -40 °C to +85 °C (Industrial) |
| Package | 28-SPDIP (Skinny Plastic DIP, 0.300 inch) |
| Mounting Type | Through-Hole (THT) |
| Self-Programming | Yes (Flash + ICD) |
| Power Management | nanoWatt Technology (multiple sleep modes) |
| RoHS Status | Compliant |
PIC18F242-I/SP Pin Configuration
| Pin 1 | MCLR/VPP — Master Clear (reset) input / programming voltage input |
| Pin 2 | RA0/AN0 — PORTA bit 0 / Analog input channel 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / Analog input channel 1 |
| Pin 4 | RA2/AN2/VREF- — PORTA bit 2 / Analog input 2 / A/D voltage reference low |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / Analog input 3 / A/D voltage reference high |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS — PORTA bit 5 / Analog input 4 / SPI slave select |
| Pin 8 | VSS — Ground reference |
| Pin 9 | OSC1/CLKI/RA7 — Oscillator crystal input / external clock input / PORTA bit 7 |
| Pin 10 | OSC2/CLKO/RA6 — Oscillator crystal output / clock output / PORTA bit 6 |
| Pin 11 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 12 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / Capture-Compare-PWM 2 |
| Pin 13 | RC2/CCP1 — PORTC bit 2 / Capture-Compare-PWM 1 |
| Pin 14 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I²C clock |
| Pin 15 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I²C data |
| Pin 16 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 17 | RC6/TX/CK — PORTC bit 6 / USART transmit / USART clock |
| Pin 18 | RC7/RX/DT — PORTC bit 7 / USART receive / USART data |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive supply voltage |
| Pin 21 | RB0/INT0 — PORTB bit 0 / External interrupt 0 |
| Pin 22 | RB1/INT1 — PORTB bit 1 / External interrupt 1 |
| Pin 23 | RB2/INT2 — PORTB bit 2 / External interrupt 2 |
| Pin 24 | RB3/CCP2 — PORTB bit 3 / Capture-Compare-PWM 2 (alt) |
| Pin 25 | RB4 — PORTB bit 4 |
| Pin 26 | RB5/PGM — PORTB bit 5 / Low-voltage ICSP programming input |
| Pin 27 | RB6/PGC — PORTB bit 6 / ICD clock |
| Pin 28 | RB7/PGD — PORTB bit 7 / ICD data |
Typical Applications
PIC18F242-I/SP is suitable for 7 applications: Industrial Sensor Interface Module, Appliance Control Board, RS-232 / RS-485 Field-Bus Node, Low-Cost Motor Control (PWM/CCP), Battery-Powered Data Logger, HVAC Thermostat Controller, Educational / Hobby Development Board.
Industrial Sensor Interface Module
The PIC18F242-I/SP is well-suited for an industrial sensor interface module because it integrates a 5-channel 10-bit A/D converter and a USART in the same silicon block, eliminating an external ADC IC and an RS-485 transceiver for low-speed nodes. Its 4.2-5.5 V supply range accepts 5 V industrial rails directly, while the -40 °C to +85 °C industrial temperature window supports unheated cabinets. The 16 KB Flash holds typical Modbus RTU or custom protocol stacks plus calibration tables in the 256-byte EEPROM, and the 23 I/O handle digital inputs, status LEDs, and a 2-wire RS-485 link through an external transceiver. nanoWatt sleep modes cut quiescent current for battery-backed installations. The 28-SPDIP package allows quick field replacement during commissioning.
Recommended
Appliance Control Board
Household appliances - washing machines, dishwashers, microwave ovens, induction cookers - benefit from the PIC18F242-I/SP's combination of 2 CCP modules (PWM), 5-channel 10-bit A/D for sensing temperature and motor current, and the enhanced USART for control-panel links. The 10 MIPS throughput at 40 MHz runs control loops comfortably while leaving CPU headroom for user-interface handling. 16 KB Flash fits a typical wash-cycle state machine, and 768 bytes of SRAM holds small data buffers without overflow. The 28-SPDIP through-hole package withstands vibration and the -40 °C to +85 °C temperature range covers unheated garages. nanoWatt idle modes drop standby consumption below energy-star targets.
Recommended
RS-232 / RS-485 Field-Bus Node
Field-bus nodes need deterministic serial communication, low cost, and long-term firmware stability - all delivered by the PIC18F242-I/SP. The enhanced USART supports RS-232 with a MAX232-class transceiver and RS-485 with a MAX485-class transceiver, with hardware address-detection for polled protocols. The 5-channel 10-bit A/D reads local analog sensors (pressure, temperature, 4-20 mA loop) without external ADC, and the 23 I/O drive relay coils, status LEDs, and digital inputs. 16 KB Flash holds Modbus RTU or DeviceNet slave stacks; 768 bytes SRAM is sufficient for typical slave applications. The 28-SPDIP package makes prototype boards easy to assemble on breadboards before PCB layout finalization.
Recommended
Low-Cost Motor Control (PWM/CCP)
Small DC-motor and brushed-motor drivers benefit from the PIC18F242-I/SP's two Capture/Compare/PWM modules that generate complementary or independent PWM signals up to the device's 40 MHz system clock. Combined with the 10-bit A/D for closed-loop current sensing, the MCU can implement simple PID motor control without external timer ICs. 16 KB Flash fits a state-machine plus current/torque loop, while 768 bytes of SRAM holds the controller's Kp/Ki tables. The 23 I/O drive direction relays, brake FETs, and encoder inputs. nanoWatt sleep modes reduce standby consumption when the motor is idle; the -40 °C to +85 °C range covers most indoor/outdoor consumer appliances.
Recommended
Battery-Powered Data Logger
Battery-powered data loggers prioritize low quiescent current and reliable non-volatile storage - exactly what the PIC18F242-I/SP provides through its nanoWatt Technology and 256-byte on-chip EEPROM. The MCU wakes periodically, reads the 10-bit A/D, stores samples to EEPROM or an external SPI Flash via the SSP port, and returns to sleep. 16 KB Flash holds the wakeup/scheduler state machine, while 768 bytes of SRAM buffers the sample array between flushes. The 4.2-5.5 V supply is compatible with a 4x AA alkaline pack (6 V with diode drop) or a USB 5 V rail. The 28-SPDIP package suits hand-soldered prototype logging nodes.
Recommended
HVAC Thermostat Controller
HVAC thermostat controllers use the PIC18F242-I/SP because it combines a 5-channel 10-bit A/D for NTC thermistor inputs, a USART for remote-temp-sensor comms, and 23 I/O for relay drivers, triac interfaces, and a character LCD. 16 KB Flash fits a multi-day scheduling algorithm plus PID heating/cooling control, and 256 bytes of EEPROM stores user preferences through power cycles. nanoWatt idle modes drop quiescent consumption in standby, helping meet ENERGY STAR limits. The -40 °C to +85 °C operating range covers both indoor thermostats and outdoor air-handler units. The 28-SPDIP package is preferred by HVAC OEMs because of its vibration resistance and easy field replacement.
Recommended
Educational / Hobby Development Board
Educational and hobby development boards favor the PIC18F242-I/SP because it has a through-hole 28-SPDIP package that fits a 0.300-inch DIP socket - ideal for breadboard and IC-socket training kits. The 16 KB Flash and 768 bytes of SRAM are large enough for C-compiler projects using MPLAB X and the XC8 toolchain, while the in-circuit debugger (ICD) interface uses RB6/RB7 so students can single-step code without removing the chip. The enhanced USART and SPI/I²C ports let learners explore all common serial protocols. 23 I/O connect to LEDs, buttons, LCDs, and hobby sensors without external mux ICs. The industrial -40 °C to +85 °C range forgives beginner-level thermal design mistakes.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F242-I/SP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F252-I/SP | PIC18F242-E/SP | PIC18F252-E/SP |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SPDIP | 28-SPDIP - same | 28-SPDIP - same | 28-SPDIP - same |
| Flash Program Memory | 16 KB | 32 KB (+100%) | 16 KB (same) | 32 KB (+100%) |
| SRAM | 768 bytes | 1.5 KB (+95%) | 768 bytes (same) | 1.5 KB (+95%) |
| EEPROM | 256 bytes | 256 bytes (same) | 256 bytes (same) | 256 bytes (same) |
| Maximum Clock Speed | 40 MHz (10 MIPS) | 40 MHz (same) | 40 MHz (same) | 40 MHz (same) |
| Operating Temperature | -40 °C to +85 °C (Industrial) | -40 °C to +85 °C (same) | -40 °C to +125 °C (Extended) | -40 °C to +125 °C (Extended) |
| A/D Converter | 10-bit, 5 channels | 10-bit, 5 channels (same) | 10-bit, 5 channels (same) | 10-bit, 5 channels (same) |
| I/O Pins | 23 | 23 (same) | 23 (same) | 23 (same) |
| Supply Voltage | 4.2 V to 5.5 V | 4.2 V to 5.5 V (same) | 4.2 V to 5.5 V (same) | 4.2 V to 5.5 V (same) |
Key Differentiators
- Mid-density Flash with 5-channel 10-bit A/D on a 28-pin footprint (vs PIC18F252-I/SP)
- Industrial -40 °C to +85 °C operating range as the default variant (vs PIC18F242-E/SP)
- True 28-SPDIP through-hole package for field-replaceable designs (vs PIC18F242-I/SO)
Design Notes
Place a 100 nF (0.1 µF) decoupling capacitor as close as physically possible to each VDD pin (pin 20) and a bulk 10 µF tantalum or aluminum electrolytic at the board entry. The PIC18F242 can source/sink 25 mA per I/O - for inductive loads add a flyback diode across relays or solenoids. If you use a switching regulator nearby, place the MCU's AVDD/VREF (when used as analog reference) on a separate filtered rail.
Do not leave MCLR floating - tie it to VDD through a 10 kΩ pull-up resistor and place a 100 nF capacitor to ground for noise filtering. Float high-impedance analog inputs (RA0-RA5) when not in use, or configure them as digital outputs to prevent shoot-through. The ICD pins RB6/RB7 must have weak pull-ups enabled in firmware if no debugger is connected, otherwise floating levels can cause spurious interrupts during boot.
Keep the oscillator traces (OSC1/OSC2 pins 9-10) short and surrounded by a ground ring to avoid coupling noise into the 40 MHz system clock. If using a crystal, place the load capacitors within 5 mm of the pins and route the crystal case to ground. For A/D accuracy, separate the analog traces (RA0-RA5) from switching signals and add a small RC filter at each analog input.
Estimated: the PIC18F242 at 40 MHz with all peripherals active typically dissipates ~120 mW. In the 28-SPDIP package the thermal resistance theta_JA is approximately 70 °C/W, giving a junction temperature rise of ~8 °C above ambient at full activity - well inside the -40 °C to +85 °C industrial window. For +125 °C extended designs (PIC18F242-E/SP) keep the chip away from heat sinks and ensure the enclosure air temperature is rated accordingly.
The USART can run up to 250 Kbaud (EUSART) or higher depending on the baud-rate generator setting. For long RS-485 cables (>10 m) use a twisted pair with 120 Ω termination at both ends and place a 100 nF bypass at each transceiver VCC. The SPI bus signals (RC3/RC4/RC5) can be sensitive to ground bounce - keep traces matched in length and avoid routing them parallel to PWM outputs.
Compliance Information
RoHS-compliant per Microchip product page. Not AEC-Q100 qualified - the automotive-grade equivalent is the PIC18F242-I/SP extended variant. Lead-free and halogen-free per Microchip material declaration.
