NXP Semiconductors MC9RS08KA4CPJ

Overview

MC9RS08KA4CPJ from NXP Semiconductors (formerly Freescale) is an 8-bit RS08-core microcontroller designed for cost-sensitive, low-power embedded control applications. It features 4 KB flash memory, 126-byte RAM, 14 GPIOs, 10-bit ADC with 12 channels, and integrated peripherals including TPM, IIC, ACMP, and MTIM timers. It operates across 1.8–5.5 V and –40°C to +85°C, supporting stop-mode wakeup via RTI, KBI, or ACMP in battery-powered sensor nodes and appliance controls.

For engineers reviewing the MC9RS08KA4CPJ datasheet, MC9RS08KA4CPJ pinout, MC9RS08KA4CPJ application, or MC9RS08KA4CPJ equivalent, this page delivers verified specifications, package mapping to 16-pin SOIC (Case 751G), functional pin roles, real-world use cases in industrial sensing and consumer control, and two validated alternative parts with documented technical and application-level differences.

Technical Context

The MC9RS08KA4CPJ implements a subset of the HC08 instruction set augmented with BGND for background debug, executing at up to 20 MHz via its internal frequency-locked-loop (FLL)-based ICS clock source-trimmable to ±0.2% resolution and ±2% deviation over voltage/temperature. Its architecture integrates dedicated low-power modes (Wait/Stop), COP watchdog with dual-clock options (1 kHz internal or bus clock), and LVD with reset/interrupt capability.

Peripherals are tightly coupled to the RS08 core: the 10-bit ADC supports automatic compare and full operation in Stop mode down to 2.7 V; the ACMP provides rail-to-rail input operation and internal bandgap reference comparison; and the TPM module delivers edge- or center-aligned PWM on two channels, with pin remapping support for PTA0/PTA1. All I/O pins include configurable slew rate, drive strength, and programmable pull-up/pull-down resistors (20–65 kΩ).

Key Specifications

Pinout & Package

MC9RS08KA4CPJ is packaged in a 16-pin SOIC (Case 751G) with 14 GPIOs (including one output-only and one input-only pin), plus VDD, VSS, RESET/VPP, and BKGD/ACMPO pins. All digital inputs feature hysteresis (0.06 × VDD) and configurable pull-ups; outputs support high/low drive modes with programmable slew rate.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC9RS08KA4CPJ, MC9RS08KA8CPJ offers double flash/RAM in identical 16-pin SOIC packaging-ideal for incremental firmware upgrades-while S08AW60A introduces CAN and larger memory but mandates new layout, power design, and qualification effort.

Availability

MC9RS08KA4CPJ is available at Aetrix Electronics and suitable for industrial sensor nodes, smart appliance control systems, and consumer remote controls requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant manufacturing.

Supply support for MC9RS08KA4CPJ 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

NXP Semiconductors develops secure, energy-efficient semiconductor solutions for automotive, industrial, and IoT applications, with roots in Freescale's legacy microcontroller expertise.

The RS08 family-including MC9RS08KA4CPJ-is engineered for ultra-low-power, cost-optimized 8-bit control in space-constrained, battery-operated devices where simplicity, reliability, and debug accessibility are critical.

FAQ

What is the maximum bus frequency supported by the MC9RS08KA4CPJ?

The MC9RS08KA4CPJ supports a maximum bus frequency of 10 MHz when operating from its trimmed internal clock source (ICS). This is achieved via the FLL-controlled DCO, which delivers 20 MHz core clock with 2× division for bus timing. External crystal oscillators up to 5 MHz are also supported through the XOSC module, with internal dividers enabling precise bus rate derivation.

Does the MC9RS08KA4CPJ support in-circuit debugging, and what interface is used?

Yes, the MC9RS08KA4CPJ supports in-circuit debugging via a single-wire background debug (BKGD) interface on PTA4. This allows full program download, breakpoint setting, register inspection, and real-time variable monitoring without requiring a dedicated debug header or additional pins-reducing PCB complexity and cost in production designs.

Can the MC9RS08KA4CPJ operate from a 1.8 V supply, and what peripherals remain functional?

Yes, the MC9RS08KA4CPJ is fully specified to operate from 1.8 V to 5.5 V. At 1.8 V, the ADC remains functional (8-bit accuracy), the ACMP operates with rail-to-rail input and internal bandgap reference, and Stop mode current drops to 1.5 μA. The I²C module functions at reduced speed (≤100 kbps), and all GPIOs retain programmable pull-up/pull-down and high-drive capability (2 mA sink/source).

How many ADC channels are accessible in the 16-pin SOIC package of the MC9RS08KA4CPJ?

The 16-pin SOIC package of the MC9RS08KA4CPJ provides access to 12 ADC input channels (ADP0–ADP11), mapped across PTA0–PTA3, PTB0–PTB3, and PTC0–PTC3. Although the 16-pin variant physically exposes only 12 pins for analog inputs, the device's internal multiplexer supports all 12 channels-enabling comprehensive analog monitoring without external muxing.

What power-saving modes does the MC9RS08KA4CPJ offer, and how do they differ?

The MC9RS08KA4CPJ offers Wait and Stop modes. Wait halts the CPU while keeping peripherals and clocks active-useful for short delays with fast wake-up (<1 μs). Stop disables the oscillator and most internal clocks, reducing current to 1.5 μA at 1.8 V; it wakes only on RTI, KBI, or ACMP events, with recovery time under 100 μs. Both modes preserve RAM and register contents.