NXP Semiconductors MC9RS08KA1CSCR

Overview

MC9RS08KA1CSCR from Freescale Semiconductor is an 8-bit RS08 microcontroller with 1024 bytes of on-chip Flash EEPROM, 63 bytes RAM, and a trimmable 20-MHz internal clock source supporting up to 10-MHz bus operation. It integrates an analog comparator (ACMP) with rail-to-rail operation and internal bandgap reference, an 8-bit modulo timer (MTIM), keyboard interrupt (KBI) ports, and background debug system - designed for ultra-low-cost, space-constrained embedded control in consumer and industrial sensors.

For engineers reviewing the MC9RS08KA1CSCR datasheet, MC9RS08KA1CSCR pinout, MC9RS08KA1CSCR application, or MC9RS08KA1CSCR equivalent, this device requires attention to its 6-pin DFN package constraints, single-byte tiny/short addressing modes, COP watchdog independence from bus clock, LVD reset capability, and ACMP operation in stop mode - all critical for battery-powered, low-pin-count MCU selection.

Technical Context

The MC9RS08KA1CSCR implements the RS08 CPU core with simplified S08 instruction set extensions including LDA/STA/CLR in short addressing ($0000–$001F) and ADD/SUB/INC/DEC in tiny addressing ($0000–$000F), enabling single-byte opcodes and reduced cycle count. Its ICS supports FEI, FBI, and FBILP operational modes with factory-trimmed 0.2% resolution and ±2% deviation over voltage/temperature.

Memory architecture features direct page access across full map via paging window, shadow PC register (SHA/SLA), and pending interrupt indication. Peripherals are tightly coupled: ACMP output feeds KBI, MTIM uses ICS-derived clocks, and BKGD pin serves dual role as debug interface and ACMP output (ACMPO) in 6-pin DFN configuration.

Key Specifications

Pinout & Package

MC9RS08KA1CSCR is housed in a 6-pin dual flat no-lead (DFN) package (case outline 98ASA00735D), measuring 2.0 × 2.0 × 0.55 mm with exposed thermal pad. This compact, lead-free RoHS-compliant package targets high-density PCB layouts and automated reflow assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC9RS08KA2CSCR, the MC9RS08KA1CSCR trades half the Flash capacity for identical low-power performance and footprint - ideal for fixed-function, cost-optimized nodes. Against MC9S08QG8CDT, it offers superior analog integration and smaller size at the expense of communication peripherals and scalability.

Availability

MC9RS08KA1CSCR is available at Aetrix Electronics and suitable for smart sensor nodes, battery-powered access controllers, industrial proximity switches, and disposable medical monitors requiring stable component supply and long-term manufacturability.

Supply support for MC9RS08KA1CSCR 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

Freescale Semiconductor (now part of NXP Semiconductors) is a fabless semiconductor company specializing in embedded processing, analog, and connectivity solutions for automotive, industrial, and consumer markets.

The RS08 family, including MC9RS08KA1CSCR, was engineered for ultra-low-cost, ultra-low-power 8-bit control in space- and budget-constrained applications - prioritizing minimal pin count, integrated analog functions, and robust debug capability over raw performance.

FAQ

What is the maximum operating frequency of the MC9RS08KA1CSCR bus clock?

The MC9RS08KA1CSCR supports a maximum bus frequency of 10 MHz, derived from its internal clock source (ICS) operating at up to 20 MHz with a programmable divide-by-2. This frequency is validated across the full 1.8–3.6 V supply range and –40°C to +105°C temperature range per Freescale's Electrical Characteristics appendix. The MC9RS08KA1CSCR achieves this while maintaining sub-1 µA stop-mode current, making it suitable for timing-critical yet power-sensitive applications.

Does the MC9RS08KA1CSCR include a hardware watchdog timer?

Yes, the MC9RS08KA1CSCR includes a Computer Operating Properly (COP) reset module that operates from a bus-independent clock source, ensuring reliable recovery even during ICS failure or bus clock stoppage. The COP timeout is software-configurable and resets the MCU if not serviced within the selected interval. This feature is fully documented in Chapter 5 of the MC9RS08KA2 Series Data Sheet, which covers MC9RS08KA1CSCR, and is active by default after reset unless explicitly disabled.

Can the MC9RS08KA1CSCR operate its analog comparator in stop mode?

Yes, the analog comparator (ACMP) in the MC9RS08KA1CSCR remains functional in stop mode and can generate interrupts or wake the MCU upon input threshold crossing. This capability is explicitly specified in Section 10.1.2.2 ("Operation in Stop Mode") of the MC9RS08KA2 Series Data Sheet. The ACMP supports rail-to-rail inputs and optional internal bandgap reference, allowing the MC9RS08KA1CSCR to perform low-power event detection without external components or wake circuitry.

What debug interface does the MC9RS08KA1CSCR support?

The MC9RS08KA1CSCR supports a single-wire Background Debug (BKGD) interface via the PTA3 pin, enabling in-circuit programming and debugging without dedicated JTAG pins. This interface provides breakpoint capability and active background mode operation, as detailed in Chapter 12 of the MC9RS08KA2 Series Data Sheet. The MC9RS08KA1CSCR uses the same BKGD protocol and register set as other RS08 devices, ensuring compatibility with standard Freescale/NXP debug tools like the DEMO9RS08KA2 evaluation board and CodeWarrior IDE.

Is the MC9RS08KA1CSCR pin-compatible with the MC9RS08KA2CSCR?

Yes, the MC9RS08KA1CSCR and MC9RS08KA2CSCR share identical 6-pin DFN packaging (98ASA00735D), pin assignments, electrical characteristics, and peripheral register maps. The only difference is Flash size: 1024 bytes in MC9RS08KA1CSCR versus 2048 bytes in MC9RS08KA2CSCR. This makes the MC9RS08KA2CSCR a direct drop-in upgrade for designs requiring more program memory, with no PCB or firmware changes needed beyond recompilation and Flash allocation adjustment.