MC908SR12MFAER - 8-Bit HC08 MCU, 12KB Flash, 48-LQFP | NXP
MPN： MC908SR12MFAER ✗ 停產MC908SR12MFAER 概覽
An 8-bit microcontroller (MCU) is a small, self-contained computer-on-a-chip that integrates a CPU, memory, and I/O peripherals on a single die. It belongs to the broader hierarchy of microcontrollers -> embedded controllers -> processors -> semiconductors. The HC08 family is NXP's (formerly Freescale's) legacy 8-bit CISC architecture, widely adopted in cost-sensitive and rugged industrial applications because of its low power consumption, deterministic interrupt response, and robust instruction set.
Key features of the MC908SR12MFAER include 12 KB on-chip Flash with in-system programmability, 512 B RAM, an internal oscillator option, an active-low external reset pin, SCI (UART) and I2C serial interfaces, multiple timer/PWM channels, and an integrated 10-bit successive-approximation ADC. The device operates from a single 3.0 V to 5.5 V supply, supporting typical 5V industrial rails and 3.3V logic systems. Security features include a programmable Flash security byte that blocks external read-back of program memory.
The HC08 core uses a von-Neumann-style unified memory map, an accumulator-based ALU, and a flexible indexed addressing mode, executing most instructions in 2 to 5 bus cycles. With 8 MHz bus clock, instruction throughput reaches roughly 2 MIPS at the rated operating voltage, sufficient for sensor interfacing, keypad scanning, simple motor control loops, and protocol translation.
Typical applications span appliance controls (washing machines, dishwashers, induction cookers), HVAC damper and fan actuators, industrial sensors, smart metering endpoints, and remote-control handsets where the integrated ADC and PWM reduce bill-of-materials cost.
When designing with this MCU, allow at least four decoupling capacitors near the VDD/VSS pairs and reserve an unused I/O line as a hardware reset or boot-mode entry - a common gotcha when migrating from larger HC08 derivatives.
直接替換替代品，適用於 MC908SR12MFAER — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： MC908SR12MFAER （相同外形與佔位） — 差異在於 ADC, RAM Size, Package, Program Memory Size, Packaging.
MC908SR12CFAE
✅ 直接替換聯絡詢價
查看資料表 →MC908AP32CFAE
✅ 直接替換聯絡詢價
查看資料表 →MC908AB32MFUE
✅ 直接替換聯絡詢價
查看資料表 →MC908AS60ACFUE-FR
✅ 直接替換聯絡詢價
查看資料表 →MC908SR12MFAER 最大額定值與電氣特性
| Core Processor | HC08 |
| Core Size | 8-Bit |
| Maximum Clock Speed | 8 MHz |
| Program Memory Size | 12 KB (12K x 8) Flash |
| RAM Size | 512 B (512 x 8) |
| Number of I/O Pins | 31 |
| 封裝 / 外殼 | 48-LQFP (7x7 mm) |
| 安裝類型 | Surface Mount |
| Supply Voltage (Vdd) | 3.0 V to 5.5 V |
| ADC | 10-bit, integrated |
| Connectivity | I2C, SCI |
| Peripherals | LVD, POR, PWM, Temperature Sensor |
| Oscillator Type | Internal |
| 工作溫度 | -40C to +85C (industrial) |
| RoHS 狀態 | Compliant |
| Lead-Free | Yes |
MC908SR12MFAER 腳位配置
| 腳位 1 | PTD0/TxD — Port D I/O / SCI transmit |
| 腳位 2 | PTD1/RxD — Port D I/O / SCI receive |
| 腳位 3 | PTD2 — Port D I/O |
| 腳位 4 | PTD3 — Port D I/O |
| 腳位 5 | VDD — Positive supply (3.0V-5.5V) |
| 腳位 6 | VSS — Ground reference |
| 腳位 7 | PTD4 — Port D I/O |
| 腳位 8 | PTD5 — Port D I/O |
| 腳位 9 | PTD6 — Port D I/O |
| 腳位 10 | PTD7 — Port D I/O |
| 腳位 11 | PTA0 — Port A I/O / ADC channel |
| 腳位 12 | PTA1 — Port A I/O / ADC channel |
| 腳位 13 | PTA2 — Port A I/O / ADC channel |
| 腳位 14 | PTA3 — Port A I/O / ADC channel |
| 腳位 15 | PTA4 — Port A I/O / ADC channel |
| 腳位 16 | PTA5 — Port A I/O / ADC channel |
| 腳位 17 | PTA6 — Port A I/O / ADC channel |
| 腳位 18 | PTA7 — Port A I/O / ADC channel |
| 腳位 19 | PTB0 — Port B I/O |
| 腳位 20 | PTB1 — Port B I/O |
| 腳位 21 | PTB2 — Port B I/O |
| 腳位 22 | PTB3 — Port B I/O |
| 腳位 23 | PTB4 — Port B I/O |
| 腳位 24 | PTB5 — Port B I/O |
| 腳位 25 | PTB6 — Port B I/O |
| 腳位 26 | PTB7 — Port B I/O |
| 腳位 27 | PTC0 — Port C I/O |
| 腳位 28 | PTC1 — Port C I/O |
| 腳位 29 | PTC2 — Port C I/O |
| 腳位 30 | PTC3 — Port C I/O |
| 腳位 31 | PTC4 — Port C I/O |
| 腳位 32 | PTC5 — Port C I/O |
| 腳位 33 | PTC6 — Port C I/O |
| 腳位 34 | PTC7 — Port C I/O |
| 腳位 35 | VDD — Positive supply (3.0V-5.5V) |
| 腳位 36 | VSS — Ground reference |
| 腳位 37 | IRQ — External interrupt request |
| 腳位 38 | RESET — Active-low external reset input |
| 腳位 39 | OSC1 — Crystal oscillator input |
| 腳位 40 | OSC2 — Crystal oscillator output |
| 腳位 41 | BKGD/MS — Background debug mode / mode select |
| 腳位 42 | SDA — I2C serial data |
| 腳位 43 | SCL — I2C serial clock |
| 腳位 44 | PTE0 — Port E I/O / Timer channel |
| 腳位 45 | PTE1 — Port E I/O / Timer channel |
| 腳位 46 | PTE2 — Port E I/O / Timer channel |
| 腳位 47 | PTE3 — Port E I/O / Timer channel |
| 腳位 48 | VPP — Flash programming voltage |
典型應用
MC908SR12MFAER 適用於 6 應用s: White Goods Appliance Control, HVAC Damper and Fan Actuator, Industrial Sensor Interface Node, Smart Metering Endpoint, Remote Control Handset, Small Appliance Motor Control.
White Goods Appliance Control
The MC908SR12MFAER is a strong fit for white-goods main boards (washing machines, dishwashers, induction cookers) where 31 I/O lines drive keypads, triac outputs, buzzer, and LCD segments. Its 10-bit ADC reads NTC temperature sensors and water-level probes with adequate resolution for thermal cut-off and load detection. The integrated PWM channels provide zero-crossing phase-angle control for AC loads up to several amps through opto-isolated triac drivers. With 12 KB Flash it accommodates well-tested 8-bit appliance firmware (state machines, wash cycles) without external memory. Designers trade higher memory MCUs for the SR12 specifically when BOM cost is the primary constraint and the firmware is mature and locked.
推薦
HVAC Damper and Fan Actuator
The MC908SR12MFAER's PWM plus 10-bit ADC pairing is well matched to HVAC damper and fan actuator modules. PWM output drives a low-side MOSFET bridge for brushless DC or variable-speed AC fan control, and the ADC continuously senses motor current via a shunt for closed-loop torque limiting. The 8-bit HC08's deterministic interrupt latency simplifies the commutation timing needed for sensorless BLDC commutation fallback modes. Operating from 3.0 V to 5.5 V matches industrial 24V-bus-derived rails. The 48-LQFP footprint leaves spare I/O for I2C temperature/humidity sensor expansion.
推薦
Industrial Sensor Interface Node
Industrial 4-20 mA loop-powered sensor transmitters benefit from the MC908SR12MFAER's 10-bit ADC, SCI/UART, and 5V-tolerant I/O. The integrated ADC reads bridge or thermistor sensors with 60 mV / LSB at 5V reference, while the SCI carries the digitized measurement over RS-485 transceivers. HC08 code density allows full calibration, linearization, and HART-style protocol state machines to fit within 12 KB Flash. The low-voltage detector (LVD) and power-on reset (POR) ensure clean startup under varying loop current. 31 I/O leaves ample headroom for switch inputs and indicator LEDs.
推薦
Smart Metering Endpoint
Single-phase smart-meter endpoints leverage the MC908SR12MFAER's low power budget, integrated ADC for current/voltage sensing, and SCI for optisol/IR communication to a handheld reader. The HC08 core's small code footprint supports IEC 62055-21 simplified metering firmware, tamper detection, and credit-token processing. With 31 I/O, the MCU directly drives segmented LCD via external charge-pump or LED indicators for status. The 48-LQFP package is small enough to fit meter-base PCBs, while its -40C to +85C industrial temperature range satisfies outdoor cabinet requirements.
推薦
Remote Control Handset
Infrared and RF remote controls rely on the MC908SR12MFAER's low active current, integrated timer/PWM, and 31 I/O for keypad matrix scanning. The HC08's interrupt-driven wakeup supports long battery life (months on the typical two-AAA-cell pack) while the SCI routes simple protocol stacks (RC5, NEC, or proprietary) over a 38 kHz carrier PWM. 12 KB Flash stores protocol tables for multiple device brands; 512 B RAM is enough for transient scan buffers. The 48-LQFP surface-mount package suits the slim handset form factor.
推薦
Small Appliance Motor Control
Compact motor-control boards for blenders, food processors, and small pumps use the MC908SR12MFAER for its PWM channels and 10-bit ADC feedback. The MCU generates complementary PWM for a 3-phase inverter or simple half-bridge driver, while the ADC samples back-EMF and DC-link current for overcurrent protection. With 8 MHz bus and HC08 throughput, software can implement sensorless or Hall-sensor BLDC commutation at moderate RPM ranges. The industrial temperature grade ensures reliable behavior near motor heat sources.
推薦
推薦產品摘要
工程參考資料，適用於 MC908SR12MFAER — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | MC908SR12CFAE | MC908AP32CFAE | MC908AB32MFUE | MC908AS60ACFUE-FR |
|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 48-LQFP (7x7 mm) | 48-LQFP - same | 48-LQFP - same | 48-LQFP - same | 48-LQFP - same |
| Core | HC08 8-Bit | HC08 8-Bit | HC08 8-Bit | HC08 8-Bit | HC08 8-Bit |
| Max Clock | 8 MHz | 8 MHz | 8 MHz | 8 MHz | 8.4 MHz |
| Program Flash | 12 KB | 12 KB | 32 KB | 32 KB | 60 KB |
| RAM | 512 B | 512 B | 1 KB | 1 KB | 2 KB |
| I/O Count | 31 | 31 | 31 | 31 | 31 |
| ADC | 10-bit | 10-bit | 10-bit | 10-bit | 10-bit |
| Connectivity | I2C, SCI | I2C, SCI | I2C, SCI | SCI, SPI | CAN, SCI, SPI |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Active | Active |
主要差異化特點
- Same 12 KB Flash footprint with stable long-term firmware base (對比MC908SR12CFAE)
- Upgrade path to 32 KB Flash in same package (對比MC908AP32CFAE)
- Larger memory plus enhanced peripherals (對比MC908AS60ACFUE-FR)
設計說明
Place a 100 nF decoupling capacitor within 5 mm of each VDD/VSS pair (the 48-LQFP exposes VDD on pins 5 and 35). Add a bulk 10 uF tantalum or ceramic cap on the main supply rail. The MC908SR12MFAER's POR is sensitive to slow Vdd rise times below 50 mV/s; ensure the rail ramps faster than this in cold-start conditions.
Keep the OSC1/OSC2 traces short (<10 mm) and shielded by a ground pour to avoid coupling noise from the PWM or ADC channels. The BKGD/MS pin (pin 41) must be accessible for in-system programming - do not route it to a connector that is only populated at production test.
Do not confuse the 48-LQFP variant (FAE) with the 64-QFP or 52-PLCC derivatives of the SR12 family; pinouts differ. Always confirm the package suffix before reworking boards. Also note that the AER suffix indicates Tape & Reel, not a different temperature grade - the operating range remains -40C to +85C for the SR12MFAE family.
The 10-bit ADC shares its input pins with Port A. Avoid driving PTA0-PTA7 with high-frequency digital signals during ADC sampling; enable the digital input buffer disable register (DIDR-style bit) on the ADC-active channels to prevent digital noise injection.
合規資訊
RoHS compliant per NXP product page. Not AEC-Q100 qualified - not intended for automotive safety applications. Lifecycle marked Obsolete on Octopart; lead-free (suffix 'AER') packaging.