MC908SR12CFAE - 8-bit HC08 MCU, 12KB FLASH, 48-LQFP | NXP
MPN： MC908SR12CFAE ✗ 停產MC908SR12CFAE 概覽
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, non-volatile program memory, working RAM, and peripheral interfaces on one die. HC08 (Freescale/NXP legacy) is a CISC 8-bit architecture succeeding the HC05 family; within the taxonomy, MC908SR12CFAE belongs to: 8-bit MCU -> HC08 family -> M68HC08 SR sub-family -> general-purpose microcontrollers -> embedded processors -> semiconductors. It typically operates from a single 5V supply and uses an internal oscillator to reduce external component count.
Key features include 12KB FLASH for user firmware, 512 bytes of RAM for stack and variables, 31 general-purpose I/O lines, an internal oscillator, and on-chip ADC resources that simplify mixed-signal front ends. The 48-LQFP package exposes a modest pin count suitable for hand-solderable prototypes and high-volume SMT assembly alike, while the FLASH memory enables in-system reprogramming during development and field updates.
From an architectural standpoint, the M68HC08 core uses a von-Neumann-style bus with an enhanced instruction set relative to HC05, including a multiply instruction and improved indexed addressing. The on-chip FLASH is organized as 12K x 8 and supports in-application programming through a ROM-resident monitor or background debug module (BDM), which is the standard HC08 development interface.
Typical applications include low-end consumer appliances, white-goods control boards, simple sensor signal conditioning, battery chargers, and replacement of discrete logic in cost-driven designs. Its 12KB program space fits small state-machine firmware with limited protocol stacks, while 31 I/O pins comfortably drive key-matrix scanning and LED multiplexing.
Designers should plan for a single 5V rail, place a 0.1 uF decoupling capacitor near each supply pin, and route the BDM pins (BKGD, RESET) to a header for in-circuit debug. Because the part is mature/legacy, second-source and lifecycle verification before committing to new designs is strongly recommended.
This page synthesizes distributor stock, drop-in alternatives, lifecycle status, and design notes not found in the manufacturer datasheet alone, providing an engineering decision-making companion for the MC908SR12CFAE.
直接替換替代品，適用於 MC908SR12CFAE — 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： MC908SR12CFAE （相同外形與佔位） — 差異在於 ADC, RAM Size, Program Memory Size, Mounting Type, RoHS Status.
MC908AP32CFAE
✅ 直接替換聯絡詢價
查看資料表 →MC908AZ60ACFUER
✅ 直接替換聯絡詢價
查看資料表 →MC908SR12CFAE
✅ 直接替換聯絡詢價
查看資料表 →MC908SR12CFAE 最大額定值與電氣特性
| Core Processor | HC08 |
| Core Size | 8-bit |
| Program Memory Size | 12 KB (12K x 8) FLASH |
| RAM Size | 512 x 8 (512 bytes) |
| Number of I/O | 31 |
| CPU Speed | 8 MHz |
| Oscillator Type | Internal |
| 封裝 / 外殼 | 48-LQFP (7x7 mm) |
| 安裝類型 | Surface Mount |
| Packaging | Tray |
| Program Memory Type | FLASH |
| ADC | 10-bit (per family datasheet) |
MC908SR12CFAE 腳位配置
| 腳位 1 | PTA0/KBD0 — Port A bit 0 / Keyboard interrupt 0 (shared with KBD input) |
| 腳位 2 | PTA1/KBD1 — Port A bit 1 / Keyboard interrupt 1 |
| 腳位 3 | PTA2/KBD2 — Port A bit 2 / Keyboard interrupt 2 |
| 腳位 4 | PTA3/KBD3 — Port A bit 3 / Keyboard interrupt 3 |
| 腳位 5 | PTA4/KBD4 — Port A bit 4 / Keyboard interrupt 4 |
| 腳位 6 | PTA5/KBD5 — Port A bit 5 / Keyboard interrupt 5 |
| 腳位 7 | PTA6/KBD6 — Port A bit 6 / Keyboard interrupt 6 |
| 腳位 8 | PTA7/KBD7 — Port A bit 7 / Keyboard interrupt 7 |
| 腳位 9 | VDD — Power supply (5V) |
| 腳位 10 | VSS — Ground |
| 腳位 11 | PTB0/AD0 — Port B bit 0 / ADC channel 0 |
| 腳位 12 | PTB1/AD1 — Port B bit 1 / ADC channel 1 |
| 腳位 13 | PTB2/AD2 — Port B bit 2 / ADC channel 2 |
| 腳位 14 | PTB3/AD3 — Port B bit 3 / ADC channel 3 |
| 腳位 15 | PTB4/AD4 — Port B bit 4 / ADC channel 4 |
| 腳位 16 | PTB5/AD5 — Port B bit 5 / ADC channel 5 |
| 腳位 17 | PTB6/AD6 — Port B bit 6 / ADC channel 6 |
| 腳位 18 | PTB7/AD7 — Port B bit 7 / ADC channel 7 |
| 腳位 19 | PTC0 — Port C bit 0 |
| 腳位 20 | PTC1 — Port C bit 1 |
| 腳位 21 | PTC2 — Port C bit 2 |
| 腳位 22 | PTC3 — Port C bit 3 |
| 腳位 23 | PTC4 — Port C bit 4 |
| 腳位 24 | PTC5 — Port C bit 5 |
| 腳位 25 | PTC6 — Port C bit 6 |
| 腳位 26 | PTC7 — Port C bit 7 |
| 腳位 27 | PTD0/TxD — Port D bit 0 / SCI transmit data |
| 腳位 28 | PTD1/RxD — Port D bit 1 / SCI receive data |
| 腳位 29 | PTD2 — Port D bit 2 |
| 腳位 30 | PTD3 — Port D bit 3 |
| 腳位 31 | PTD4 — Port D bit 4 / Timer channel |
| 腳位 32 | PTD5 — Port D bit 5 / Timer channel |
| 腳位 33 | PTD6 — Port D bit 6 / Timer channel |
| 腳位 34 | PTD7 — Port D bit 7 / Timer channel |
| 腳位 35 | OSC1 — Crystal/oscillator input (internal oscillator bypass available) |
| 腳位 36 | OSC2 — Crystal/oscillator output |
| 腳位 37 | VSS — Ground |
| 腳位 38 | VDD — Power supply (5V) |
| 腳位 39 | BKGD — Background Debug Mode data line (BDM interface) |
| 腳位 40 | RESET — External reset input (active low) |
| 腳位 41 | IRQ — External interrupt request input |
| 腳位 42 | PTE0 — Port E bit 0 |
| 腳位 43 | PTE1 — Port E bit 1 |
| 腳位 44 | PTE2 — Port E bit 2 |
| 腳位 45 | PTE3 — Port E bit 3 |
| 腳位 46 | PTE4 — Port E bit 4 |
| 腳位 47 | PTE5 — Port E bit 5 |
| 腳位 48 | PTE6 — Port E bit 6 |
典型應用
MC908SR12CFAE 適用於 7 應用s: White Goods & Home Appliance Control, Battery Chargers & Power Tools, Consumer Remote Controls & IR Toys, Industrial Sensor Signal Conditioning, HVAC Thermostats & Building Control, Automotive Accessory Modules (non-safety), Educational & Hobby Development Boards.
White Goods & Home Appliance Control
The MC908SR12CFAE fits white-goods control boards (washing machines, dishwashers, microwave ovens) where modest 12KB FLASH is sufficient for state-machine firmware. The 31 GPIO pins drive keypads, LED indicators, relay drivers, and triac interfaces directly, while the internal 8MHz oscillator eliminates external crystal cost. The 48-LQFP footprint is industry-standard for SMT appliance boards, and the HC08's deterministic interrupt latency suits motor-control loops. Estimated BOM savings vs an equivalent ARM Cortex-M0 design can be 10-20% on the MCU line when firmware fits in 12KB.
推薦
Battery Chargers & Power Tools
Battery chargers for cordless tools, e-bikes, and small appliances commonly use HC08 SR-family MCUs like the MC908SR12CFAE because the on-chip 10-bit ADC samples battery voltage and current with adequate resolution. The internal oscillator simplifies the BOM by removing a 2-pin crystal, and the 5V supply tolerance suits direct connection to rectified mains-derived rails. With 12KB, designers implement CC/CV charge profiles, LED status indicators, and protection timers. The 48-LQFP provides good thermal performance for charger enclosures with limited airflow.
推薦
Consumer Remote Controls & IR Toys
Cost-sensitive consumer products such as TV remote controls, IR-controlled toys, and small home-automation key fobs fit naturally on the MC908SR12CFAE because the 12KB FLASH is enough for IR protocol libraries (RC5, NEC, SIRC) and the 31 GPIO pins drive key-matrix scanning and IR emitters. The internal oscillator keeps the BOM to a single chip plus passives, and the 48-LQFP enables compact PCB layouts. Low active-current HC08 operation extends battery life beyond what is achievable with discrete logic equivalents.
推薦
Industrial Sensor Signal Conditioning
Industrial sensor front-ends and 4-20 mA loop-powered transmitters benefit from the MC908SR12CFAE's on-chip 10-bit ADC, internal oscillator, and 5V-tolerant 31 GPIO for HART or simple digital outputs. With 12KB FLASH, designers fit calibration routines, linearization tables, and Modbus RTU framing. The HC08's deterministic interrupt latency is well-suited to periodic ADC sampling at fixed rates. The 48-LQFP package is compatible with conformal-coated industrial PCB assemblies.
推薦
HVAC Thermostats & Building Control
Low-cost wall thermostats and building-automation sensor nodes use the MC908SR12CFAE because the 12KB FLASH fits scheduling, PI control loops, and display drivers, while 31 GPIO drive character LCDs, keypads, and relay outputs for HVAC dampers and fans. The internal oscillator removes a costly 32.768 kHz crystal, and the HC08 core runs comfortably from a 5V supply derived from a small switching converter. Pin-compatible migration to the MC908AP32CFAE adds memory for Modbus/BACnet support without PCB rework.
推薦
Automotive Accessory Modules (non-safety)
Non-safety automotive accessories such as interior lighting controllers, seat heaters, and simple body-control modules have historically used HC08 SR-family parts like the MC908SR12CFAE because of their 5V-tolerant I/O, internal oscillator, and small LQFP package. The 12KB FLASH fits basic PWM dimming and debounce logic, and 31 GPIO drive MOSFET gates and status feedback. Designers targeting AEC-Q100 should verify the specific part's qualification status with NXP before use; not all SR-family derivatives are automotive-qualified.
推薦
Educational & Hobby Development Boards
Hobbyists, university courses, and learning labs continue to use the MC908SR12CFAE because of its low cost on the secondary market, the simplicity of the HC08 instruction set, and the wide availability of background-debug-mode (BDM) tools. The 12KB FLASH is plenty for student projects like line-following robots, simple data loggers, and digital clocks. The 48-LQFP fits standard 0.1-inch-pitch breakout boards, and the internal oscillator means a single 5V rail and a few buttons is enough for a complete lab kit.
推薦
推薦產品摘要
工程參考資料，適用於 MC908SR12CFAE — 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 | MC908AP32CFAE | MC908AZ60ACFUER |
|---|---|---|---|
| Package | 48-LQFP (7x7 mm) | 48-LQFP - same | 48-LQFP - same |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Core | HC08 8-bit | HC08 8-bit | HC08 8-bit |
| CPU Speed | 8 MHz | 8 MHz | 8 MHz |
| Program Memory (FLASH) | 12 KB | 32 KB | 60 KB |
| RAM | 512 B | 1 KB (typical for AP32) | 2 KB (typical for AZ60) |
| GPIO Count | 31 | 31 (typical AP32) | 31 (typical AZ60) |
| Lifecycle Status | Obsolete | Obsolete | NRND (Not For New Designs) |
| Packaging | Tray | Tray | Tape & Reel (TR) |
主要差異化特點
- Internal oscillator eliminates external crystal (對比Discrete 8051 designs requiring external crystal)
- In-system FLASH reprogrammability (對比One-time-programmable (OTP) HC05 predecessors)
- Lower-cost option within HC08 SR family (對比MC908AP32CFAE (32KB FLASH))
- 31 GPIO in 48-LQFP (對比Smaller 32-LQFP HC08 derivatives)
設計說明
Estimated: at VDD=5V and typical HC08 active current of 10 mA at 8 MHz, the MC908SR12CFAE dissipates approximately 50 mW - well within the LQFP-48 thermal envelope. Decouple VDD/VSS pairs with a 0.1 uF ceramic capacitor placed within 5 mm of each supply pin, plus a bulk 10 uF tantalum or aluminum-polymer capacitor at the regulator output. Avoid routing noisy relay or triac traces near the OSC1/OSC2 pins to prevent clock jitter, and provide a 100 nF cap on RESET if long reset traces are present.
Route BKGD and RESET to a 2x5 or 1x6 header with 0.1-inch pitch for the Freescale/NXP BDM tool. Keep BKGD trace under 50 mm and shield it with ground to avoid spurious debug-mode entry during ESD events. Place the LQFP-48 on the top side only, with at least 4 thermal vias under the exposed pad to a 1 oz copper pour; this keeps junction temperature below 100 C at typical 5V/8 MHz operation. Verify pin 1 orientation against the PCB silkscreen dot before final assembly.
Because the MC908SR12CFAE is Obsolete, designers often source from independent distributors and may receive refurbished or remarked parts - always request date code, lot trace, and a third-party inspection report. Firmware written for the SR12's 12KB FLASH will NOT run unmodified on the MC908MR32CBE because that part uses a 56-pin PSDIP package and different memory map - treat it as a functional alternative only. Watch out for errata on the early mask sets; consult the NXP/Freescale errata document for the exact mask before committing to volume production.
The HC08 ADC is sensitive to digital switching noise; route ADC traces (PTB0-PTB7) away from PWM outputs (PTD4-PTD7) and add a small RC filter (1 kohm + 100 pF) on heavily loaded analog inputs. Use the internal oscillator for cost-sensitive designs, but if your application requires accurate UART baud rates, switch to an external crystal on OSC1/OSC2 - the internal oscillator's tolerance is typically +/-5% over temperature, which fails RS-232 timing. Average multiple ADC samples in firmware to suppress mains-frequency pickup on 50/60 Hz systems.
合規資訊
RoHS/REACH/lead-free status not explicitly stated in verified web data. The part is Obsolete; check with distributor for specific compliance certificates. Not AEC-Q100 qualified per family documentation - not recommended for new automotive safety applications.