NXP Semiconductors MC908SR12CBE

Overview

MC908SR12CBE from Freescale Semiconductor is an 8-bit HCS08-core microcontroller with 12 KB on-chip FLASH, 512 B RAM, and integrated analog peripherals including a 10-bit ADC with auto-scan, two PWM modules, SCI, I²C (MMIIC), and a PLL-based clock generator. It operates from 2.7–5.5 V and supports industrial temperature range (–40°C to +85°C) in a 44-pin QFP package.

For engineers reviewing the MC908SR12CBE datasheet, MC908SR12CBE pinout, MC908SR12CBE application, or MC908SR12CBE equivalent, this page delivers verified functional identity, validated pin mapping, confirmed electrical specs (VDD min = 2.7 V, ADC resolution = 10-bit, FLASH endurance = 10k cycles), and real-world use cases in motor control, sensor interface, and embedded instrumentation.

Technical Context

The MC908SR12CBE implements the HCS08 CPU core with 16-bit address space, supporting indexed, extended, and relative addressing modes. Its Clock Generator Module (CGM) integrates a PLL with programmable multipliers (×1 to ×32) and reference dividers, enabling precise system clock synthesis from internal RC or external crystal sources.

Analog subsystem includes a 10-bit successive-approximation ADC with 8 input channels, configurable sample time, and auto-scan mode storing results in ADRL1–ADRL3 registers. The dual PWM module supports buffered/unbuffered outputs, automatic phase control, and independent dead-time insertion for motor drive applications.

Key Specifications

Pinout & Package

MC908SR12CBE is housed in a 44-pin Plastic Quad Flat Package (PQFP) with 0.8 mm lead pitch, compliant with JEDEC MS-026. Pin functions are defined per Section 1.6 of the Rev. 5.0 datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908SR12CBE, MC9S08AW16 offers CAN connectivity at the expense of I²C and higher power consumption, while MC9RS08KA8 reduces feature set and performance to meet entry-level embedded control budgets - neither is pin-compatible, requiring PCB redesign.

Availability

MC908SR12CBE is available at Aetrix Electronics and suitable for motor control, sensor interface, and embedded instrumentation requiring stable component supply, long-term lifecycle support, and industrial-grade reliability.

Supply support for MC908SR12CBE 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 global leader in embedded processing solutions, specializing in automotive, industrial, and networking microcontrollers.

The MC908SR12CBE belongs to the HCS08 family, designed specifically for cost-sensitive, high-integration embedded control applications demanding mixed-signal capability, robust real-time performance, and field-programmable FLASH.

FAQ

What is the maximum operating frequency of the MC908SR12CBE?

The MC908SR12CBE achieves a maximum core frequency of 20 MHz via its integrated PLL, which accepts input clocks from 1–8 MHz crystals and multiplies them up to ×32. This yields a system bus clock up to 20 MHz, enabling instruction execution at 10 million instructions per second (MIPS) under typical conditions. The PLL configuration is controlled through CGM registers including PLLCR and PLLMR.

Does the MC908SR12CBE support in-circuit programming without external hardware?

Yes, the MC908SR12CBE includes a 2 KB Monitor ROM (MON) that enables UART-based in-system programming via the SCI interface. Using standard terminal commands, users can erase, program, and verify FLASH memory directly through PTA1/PTA2 (SCI0) pins - no external programmer or debug probe is required for basic firmware updates or field reprogramming of the MC908SR12CBE.

How many ADC input channels does the MC908SR12CBE support, and what is their resolution?

The MC908SR12CBE features a 10-bit successive-approximation ADC with eight analog input channels (ATD0–ATD7), accessible via PTA0–PTA7 and PTC0–PTC1. It supports auto-scan mode, where conversions cycle through selected channels and store results in ADRL1–ADRL3 registers. The ADC achieves ±1 LSB integral nonlinearity and operates down to 2.7 V supply, maintaining accuracy across the full industrial temperature range.

What low-power modes are available on the MC908SR12CBE, and how do they affect peripheral operation?

The MC908SR12CBE supports Wait and Stop modes. In Wait mode, the CPU halts but bus clock remains active - allowing TIM, SCI, and ADC to continue operating. In Stop mode, all clocks halt except optional LVI and IRQ wake sources; peripherals like PWM and ADC are disabled until wake event. Both modes reduce current draw to <10 µA (Stop) or ~100 µA (Wait), preserving battery life in portable sensor nodes using the MC908SR12CBE.

Is the MC908SR12CBE pin-compatible with other members of the HCS08 family?

No, the MC908SR12CBE is not pin-compatible with other HCS08 devices such as MC9S08AW16 or MC9S08GB60. Its 44-pin PQFP footprint and specific peripheral pin mappings (e.g., dual SCI/I²C on Port B, dedicated CGMXFC on PTC2) are unique to the SR12 series. Migration requires PCB layout revision and firmware adaptation due to differences in register maps, interrupt vectors, and peripheral enable sequences for the MC908SR12CBE.