NXP Semiconductors MC908SR12CFAE

Overview

MC908SR12CFAE from NXP (formerly Freescale) is an 8-bit HCS08 microcontroller with 12 KB on-chip FLASH, 512 B RAM, and integrated analog peripherals including a 10-bit ADC, PWM, and analog comparator. It operates at up to 8 MHz bus frequency, supports 3–5.5 V supply, and targets embedded control in automotive body electronics and industrial sensor interfaces.

For engineers reviewing the MC908SR12CFAE datasheet, MC908SR12CFAE pinout, MC908SR12CFAE application, or MC908SR12CFAE equivalent, key selection criteria include its 44-pin LQFP package, PLL-based clock generation, monitor ROM for in-system programming, and dual I²C-compatible serial interfaces - all critical for resource-constrained real-time control designs.

Technical Context

The MC908SR12CFAE 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 multiplier (×1 to ×32) and reference divider, enabling precise bus clock synthesis from internal RC or external crystal sources.

System integration includes a 16-bit Timer Interface Module (TIM) with input capture, output compare, and PWM channels; a 10-bit, 8-channel ADC with auto-scan mode and configurable voltage references; and dual multi-master IIC interfaces (MMIIC0/MMIIC1) compliant with Philips I²C specification v2.1.

Key Specifications

Pinout & Package

MC908SR12CFAE is housed in a 44-pin LQFP (7 mm × 7 mm, 0.8 mm pitch) package with exposed thermal pad. Pin functions are defined per Section 1.5 (Pin Assignments) and Section 1.6 (Pin Functions) 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 MC9S08AW16CFUE, the MC908SR12CFAE offers lower cost and smaller memory footprint for simpler control tasks, while S9KEAZ128AMLH provides scalable performance at the expense of increased design complexity and layout revision.

Availability

MC908SR12CFAE is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor nodes, appliance motor controllers, and smart HVAC actuators requiring stable component supply across extended product lifecycles.

Supply support for MC908SR12CFAE 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, and IoT applications.

The MC908SR12CFAE belongs to the legacy HCS08 microcontroller family, designed specifically for cost-sensitive, low-power embedded control in harsh environments where reliability, analog integration, and long-term supply stability are critical.

FAQ

What is the maximum bus frequency supported by the MC908SR12CFAE?

The MC908SR12CFAE supports a maximum bus frequency of 8 MHz, achieved via its integrated PLL-based Clock Generator Module (CGM). This frequency is programmable using the PLL multiplier and reference divider registers, and remains stable across the full operating temperature range (–40 °C to +105 °C) and supply voltage (3.0–5.5 V).

Does the MC908SR12CFAE include a hardware debug interface?

No, the MC908SR12CFAE does not include a dedicated hardware debug interface like BDM or SWD. Instead, it relies on its 2 KB Monitor ROM (MON) for in-system programming and limited debugging via UART commands. Debugging requires external UART connection and use of Freescale's MON08 protocol - no JTAG or background debugger is integrated.

Can the MC908SR12CFAE operate from an internal oscillator only?

Yes, the MC908SR12CFAE can operate using its internal 31.25 kHz RC oscillator without external crystals or resonators. The Clock Generator Module (CGM) can multiply this internal clock via PLL to generate the required bus clock (e.g., 4 MHz or 8 MHz), enabling fully self-contained operation for cost-sensitive or space-constrained designs.

What analog input channels are available on the MC908SR12CFAE ADC?

The MC908SR12CFAE features an 8-channel, 10-bit ADC with inputs mapped to PTC0–PTC3 (ATD0–ATD3) and PTA0–PTA3 (ATD4–ATD7). All channels support single-ended operation with selectable voltage references (VREFH/VREFL), and the auto-scan mode allows sequential conversion of up to four channels without CPU intervention.

Is the MC908SR12CFAE pin-compatible with other HCS08 family members?

The MC908SR12CFAE is not universally pin-compatible across the HCS08 family. While it shares the 44-pin LQFP footprint with devices like MC9S08AW16CFUE, pin functions differ significantly - especially for peripheral signals (e.g., I²C, SCI, PWM). Direct replacement requires verification of signal mapping, register compatibility, and electrical loading per the respective datasheets.