NXP Semiconductors MC9RS08KA8CTG

Overview

MC9RS08KA8 from NXP Semiconductors (formerly Freescale) is an 8-bit RS08-core microcontroller designed for cost-sensitive, low-power embedded control applications. It delivers up to 20 MHz CPU operation across 1.8–5.5 V supply and –40°C to +85°C temperature range, integrates 8 KB flash and 254-byte RAM, and supports real-time interrupt wakeup from stop mode - enabling use in battery-powered sensor nodes and smart peripherals.

For engineers reviewing the MC9RS08KA8 datasheet, MC9RS08KA8 pinout, MC9RS08KA8 application, or MC9RS08KA8 equivalent, key selection considerations include its single-wire background debug interface, 10-bit 12-channel ADC with stop-mode operation, internal FLL-based clock system with ±2% total deviation over voltage/temperature, and integrated analog comparator with rail-to-rail input and internal bandgap reference.

Technical Context

The MC9RS08KA8 implements a streamlined RS08 CPU core - a subset of the HC08 instruction set augmented with BGND - optimized for minimal code footprint and deterministic interrupt latency. Its clock architecture combines a precision-trimmed internal frequency-locked loop (FLL) capable of generating up to 20 MHz DCO output and a Pierce oscillator supporting external crystals from 31.25 kHz to 5 MHz.

System-level protection includes a configurable COP watchdog (with dedicated 1 kHz clock option), low-voltage detect with reset/interrupt, illegal opcode/address detection, and flash block protection. Peripherals are tightly coupled to power management: the ADC, ACMP, and RTI can all wake the device from stop mode, and I/O pins support programmable slew rate, drive strength, and pull-up/pull-down resistors.

Key Specifications

Pinout & Package

MC9RS08KA8 is available in 16-pin SOIC (Case 751G), PDIP (Case 648), and TSSOP (Case 948F) packages, and 20-pin SOIC (Case 751D) and PDIP (Case 738C) packages. The 16-pin variant provides 14 GPIOs (including one output-only and one input-only pin); the 20-pin variant provides 18 GPIOs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit microcontroller applications.

Compared with MC9RS08KA4, the MC9RS08KA8 offers double flash/RAM for complex state machines or larger calibration tables; compared with S9KEAZ128AMLH, it provides lower gate count, smaller footprint, and proven qualification for cost-driven industrial applications - making it optimal for stable, volume production where feature creep is constrained.

Availability

MC9RS08KA8 is available at Aetrix Electronics and suitable for smart home sensor nodes, industrial panel controllers, medical wearable monitors, and automotive body control subsystems requiring stable component supply and long-term manufacturing continuity.

Supply support for MC9RS08KA8 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 is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, IoT, and mobile applications, with deep heritage in microcontroller innovation dating back to Motorola and Freescale.

The MC9RS08KA8 belongs to NXP's RS08 family - a line of ultra-low-cost, low-power 8-bit MCUs engineered for simple embedded control in price-sensitive, high-volume applications such as appliances, lighting, and basic automation.

FAQ

What is the maximum operating frequency of the MC9RS08KA8 CPU core?

The MC9RS08KA8 CPU core operates at up to 20 MHz across its full 1.8–5.5 V supply range and –40°C to +85°C temperature range. This frequency is achieved using the internal FLL with trimmed DCO output; external crystal operation supports up to 5 MHz input, which the FLL multiplies to reach the 20 MHz bus clock. The MC9RS08KA8 datasheet specifies this as the maximum guaranteed bus frequency under all operating conditions.

Does the MC9RS08KA8 support debugging during active operation?

Yes, the MC9RS08KA8 supports in-circuit debugging via its single-wire background debug (BKGD) interface on PTA4. This allows real-time firmware inspection, register read/write, and breakpoint setting without halting peripheral operation - critical for validating timing-sensitive functions like PWM or ADC sampling. The MC9RS08KA8 implements hardware breakpoint logic that retains execution context during debug sessions.

Can the MC9RS08KA8 ADC operate while the device is in stop mode?

Yes, the MC9RS08KA8 ADC is fully functional in stop mode. When enabled with the asynchronous ADC clock, it draws only 79–165 μA additional current (depending on VDD and temperature) and completes conversions in 2.5 μs. This capability allows the MC9RS08KA8 to perform periodic sensor readings without exiting low-power state - a key enabler for battery-operated applications where average current must remain below 10 μA.

What clock sources are available for the MC9RS08KA8, and how accurate are they?

The MC9RS08KA8 offers two primary clock sources: an internal FLL with trimmed DCO (±2% total deviation over voltage and temperature, 0.2% resolution) and an external Pierce oscillator supporting crystals/resonators from 31.25 kHz to 5 MHz. The FLL uses an internal reference trimmed at production to achieve its accuracy; no external components are needed for basic timing. The MC9RS08KA8 does not require an external crystal for most control applications, reducing BOM cost and board space.

How many GPIO pins does the MC9RS08KA8 provide in its 16-pin package?

The MC9RS08KA8 in its 16-pin SOIC, PDIP, or TSSOP package provides 14 general-purpose I/O pins - including PTA0–PTA5, PTB0–PTB7, and PTC0–PTC3 - with one output-only pin (PTB4 in 16-pin mapping) and one input-only pin (PTA5 configured as RESET). All GPIOs support programmable pull-up/pull-down resistors, slew rate control, and configurable drive strength, making the MC9RS08KA8 highly adaptable to diverse interface requirements.