MC9S12B256MFUE - 16-bit HCS12 MCU, 256KB Flash | NXP
MPN: MC9S12B256MFUE ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $36.37 | $36.37 |
| 10 | $32.45 | $324.50 |
| 100 | $28.2 | $2,820.00 |
| 500 | $24.85 | $12,425.00 |
| 1,000 | $21.6 | $21,600.00 |
MC9S12B256MFUE Overview
A microcontroller (MCU) is an integrated circuit that combines a CPU core, volatile memory (RAM), non-volatile program memory (Flash/ROM), and a configurable set of peripherals (timers, ADCs, communication interfaces) on a single die. The HCS12 core is a 16-bit CISC architecture from NXP that evolved from the HC11/HC12 lineage, optimized for automotive and industrial real-time control. The S12B family sits within the broader NXP 16-bit MCU hierarchy: HCS12 core -> S12B sub-family -> MC9S12B series -> specific MPNs with different memory/peripheral mixes.
Key features of the MC9S12B256MFUE include: 256KB Flash (256K x 8) with Fast Page Erase, 12KB RAM, 4KB EEPROM, a 10-bit ADC, an 8-channel PWM module, plus multiple communication interfaces including CAN 2.0 (msCAN), SCI, SPI, and I2C. The on-chip Enhanced Capture Timer (ECT) provides six 16-bit channels for input capture and output compare, supporting precise event timing required for engine and chassis control.
The device operates from 2.35V to 5.5V supply, supports -40C to +125C junction temperature, and integrates a PLL-based clock generator for flexible bus-speed scaling. The BDM (Background Debug Mode) interface and on-chip single-wire debug simplify in-circuit programming and field firmware updates. Internal architecture pairs the HCS12 CPU with a 32-bit HCS12X-style peripheral bus for higher throughput on time-critical registers.
Typical applications include automotive body and chassis modules, CAN-connected sensor nodes, industrial PLCs, HVAC controllers, and LIN/CAN bridges. Engineered for automotive multiplexing, the S12B family allows designers to swap memory or peripheral options without PCB rework, reducing time-to-market for tier-1 OEMs and aftermarket modules.
When designing with this MCU, place decoupling capacitors within 5 mm of each VDD/VSS pair, route the resonator/oscillator traces with a guarded ground channel, and keep CAN-H/CAN-L differential pairs at 100 ohm impedance. The NRND designation means NXP has flagged the part for limited future support - designers of new programs should evaluate S12XE or S12Z successors at the architectural level.
This page synthesizes distributor inventory, drop-in alternatives drawn from the same S12B and S12XE pin-compatible families, and practical design notes beyond what is in the standalone datasheet.
Drop-in alternatives for MC9S12B256MFUE — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MC9S12B256MFUE (same form factor and footprint) — differing in Package, ADC, Core, Program Memory Size, Data Bus Width.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC9S12B128MFUE
✅ Drop-In✓ In Stock
$10.4 / Unit
View Datasheet →MC9S12B512MFUE
✅ Drop-In📋 Reference alternative (not in catalog)
MC9S12DT256MFUE
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$19.2 / Unit
View Datasheet →MC9S12DJ256MFUE
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →MC9S12GC32MFUE
✅ Drop-In✓ In Stock
$6.1 / Unit
View Datasheet →MC9S12D32MFUE
✅ Drop-In✓ In Stock
$26.4032 / Unit
View Datasheet →MC9S12XA256VAA
✅ Drop-In📋 Reference alternative (not in catalog)
MC9S12B256MFUE Maximum Ratings & Electrical Characteristics
| Core | HCS12 (16-bit CISC) |
| CPU Family | S12B (MC9S12B series) |
| Maximum CPU Clock | 25 MHz |
| Program Memory (Flash) | 256 KB (256K x 8) |
| RAM | 12 KB |
| EEPROM | 4 KB |
| Supply Voltage | 2.35 V to 5.5 V |
| ADC | 10-bit, 8-channel |
| PWM Module | 8-channel, 8-bit |
| CAN (msCAN) | 1 x CAN 2.0A/B |
| SCI / SPI / I2C | Yes (1 each) |
| Enhanced Capture Timer | 6 x 16-bit channels |
| Operating Temperature | -40 C to +125 C (junction) |
| Package | 80-QFP, 14 x 14 mm, 1.0 mm pitch |
| Mounting Type | Surface Mount |
| MSL Level | 3 (168 hours) |
| RoHS Status | Compliant |
| Debug Interface | BDM (Background Debug Mode) |
| Lifecycle | NRND (Not Recommended for New Designs) |
MC9S12B256MFUE Pin Configuration
| Pin 1 | VDDR — Voltage regulator bypass / internal regulator output |
| Pin 2 | VDD1 — Digital I/O supply voltage (2.35V to 5.5V) |
| Pin 3 | VSS1 — Digital I/O ground |
| Pin 4 | VDD2 — Digital I/O supply voltage |
| Pin 5 | VSS2 — Digital I/O ground |
| Pin 6 | BKGD — Background Debug Mode (BDM) serial communication |
| Pin 7 | RESET — External reset input (active low, internal pull-up) |
| Pin 8 | XTAL — Crystal oscillator input / external clock input |
| Pin 9 | EXTAL — Crystal oscillator feedback |
| Pin 10 | PE7 — Port E bit 7 (general I/O, XIRQ interrupt capable) |
| Pin 11 | PE6 — Port E bit 6 (general I/O) |
| Pin 12 | PE5 — Port E bit 5 (general I/O) |
| Pin 13 | PE4 — Port E bit 4 (general I/O) |
| Pin 14 | PE3 — Port E bit 3 (general I/O) |
| Pin 15 | PE2 — Port E bit 2 (general I/O) |
| Pin 16 | PE1 — Port E bit 1 (general I/O, IRQ interrupt) |
| Pin 17 | PE0 — Port E bit 0 (general I/O, IRQ interrupt) |
| Pin 18 | PA7 — Port A bit 7 (general I/O, address/data bus) |
| Pin 19 | PA6 — Port A bit 6 (general I/O) |
| Pin 20 | PA5 — Port A bit 5 (general I/O) |
| Pin 21 | PA4 — Port A bit 4 (general I/O) |
| Pin 22 | PA3 — Port A bit 3 (general I/O) |
| Pin 23 | PA2 — Port A bit 2 (general I/O) |
| Pin 24 | PA1 — Port A bit 1 (general I/O) |
| Pin 25 | PA0 — Port A bit 0 (general I/O) |
| Pin 26 | PB7 — Port B bit 7 (general I/O) |
| Pin 27 | PB6 — Port B bit 6 (general I/O) |
| Pin 28 | PB5 — Port B bit 5 (general I/O) |
| Pin 29 | PB4 — Port B bit 4 (general I/O) |
| Pin 30 | PB3 — Port B bit 3 (general I/O) |
| Pin 31 | PB2 — Port B bit 2 (general I/O) |
| Pin 32 | PB1 — Port B bit 1 (general I/O) |
| Pin 33 | PB0 — Port B bit 0 (general I/O) |
| Pin 34 | PC7 — Port C bit 7 (general I/O) |
| Pin 35 | PC6 — Port C bit 6 (general I/O) |
| Pin 36 | PC5 — Port C bit 5 (general I/O) |
| Pin 37 | PC4 — Port C bit 4 (general I/O) |
| Pin 38 | PC3 — Port C bit 3 (general I/O) |
| Pin 39 | PC2 — Port C bit 2 (general I/O) |
| Pin 40 | PC1 — Port C bit 1 (general I/O) |
| Pin 41 | PC0 — Port C bit 0 (general I/O) |
| Pin 42 | PD7 — Port D bit 7 (CAN / I/O shared) |
| Pin 43 | PD6 — Port D bit 6 (CAN / I/O shared) |
| Pin 44 | PD5 — Port D bit 5 (PWM / I/O shared) |
| Pin 45 | PD4 — Port D bit 4 (PWM / I/O shared) |
| Pin 46 | PD3 — Port D bit 3 (PWM / I/O shared) |
| Pin 47 | PD2 — Port D bit 2 (PWM / I/O shared) |
| Pin 48 | PD1 — Port D bit 1 (PWM / I/O shared) |
| Pin 49 | PD0 — Port D bit 0 (PWM / I/O shared) |
| Pin 50 | PAD07 — Port AD bit 7 (analog/digital input, 10-bit ADC) |
| Pin 51 | PAD06 — Port AD bit 6 (analog/digital input, 10-bit ADC) |
| Pin 52 | PAD05 — Port AD bit 5 (analog/digital input, 10-bit ADC) |
| Pin 53 | PAD04 — Port AD bit 4 (analog/digital input, 10-bit ADC) |
| Pin 54 | PAD03 — Port AD bit 3 (analog/digital input, 10-bit ADC) |
| Pin 55 | PAD02 — Port AD bit 2 (analog/digital input, 10-bit ADC) |
| Pin 56 | PAD01 — Port AD bit 1 (analog/digital input, 10-bit ADC) |
| Pin 57 | PAD00 — Port AD bit 0 (analog/digital input, 10-bit ADC) |
| Pin 58 | VRH — ADC reference high voltage |
| Pin 59 | VRL — ADC reference low voltage |
| Pin 60 | VDD3 — Digital I/O supply |
| Pin 61 | VSS3 — Digital I/O ground |
| Pin 62 | PP7 — Port P bit 7 (PWM channel 7) |
| Pin 63 | PP6 — Port P bit 6 (PWM channel 6) |
| Pin 64 | PP5 — Port P bit 5 (PWM channel 5) |
| Pin 65 | PP4 — Port P bit 4 (PWM channel 4) |
| Pin 66 | PP3 — Port P bit 3 (PWM channel 3) |
| Pin 67 | PP2 — Port P bit 2 (PWM channel 2) |
| Pin 68 | PP1 — Port P bit 1 (PWM channel 1) |
| Pin 69 | PP0 — Port P bit 0 (PWM channel 0) |
| Pin 70 | PS7 — Port S bit 7 (SPI / I2C / SCI shared) |
| Pin 71 | PS6 — Port S bit 6 (SPI / I2C / SCI shared) |
| Pin 72 | PS5 — Port S bit 5 (SPI / I2C / SCI shared) |
| Pin 73 | PS4 — Port S bit 4 (SPI / I2C / SCI shared) |
| Pin 74 | PS3 — Port S bit 3 (SPI / I2C / SCI shared) |
| Pin 75 | PS2 — Port S bit 2 (SPI / I2C / SCI shared) |
| Pin 76 | PS1 — Port S bit 1 (SPI / I2C / SCI shared) |
| Pin 77 | PS0 — Port S bit 0 (SPI / I2C / SCI shared) |
| Pin 78 | XFC — PLL loop filter capacitor |
| Pin 79 | VDD4 — Digital I/O supply |
| Pin 80 | VSS4 — Digital I/O ground |
Typical Applications
MC9S12B256MFUE is suitable for 7 applications: Automotive Body Control Module (BCM), Industrial Sensor Hub with CAN Output, HVAC Climate Control Unit, LIN/CAN Gateway Bridge, Battery Management Module (12V/24V Automotive), Automotive Instrument Cluster Auxiliary MCU, CAN-Connected Lighting Module.
Automotive Body Control Module (BCM)
The MC9S12B256MFUE is well suited to body control modules because it integrates 256 KB Flash for door/window/lamp logic plus a msCAN port for chassis-class networking. The 10-bit ADC reads ratiometric switches and battery voltage (up to 5.5 V tolerant) directly, and the 8-channel PWM drives LED dimming and mirror motors at 8-bit resolution. Compared with a discrete + LIN approach, putting the algorithm on the HCS12 core removes an external logic chip and reduces BOM cost. The 12 KB SRAM and 4 KB EEPROM are sufficient for storing learned trim positions and fault codes. Designers should budget 5-8 KB of Flash for the BDM-friendly bootloader used in field firmware updates.
Recommended
Industrial Sensor Hub with CAN Output
The MC9S12B256MFUE serves as a CAN-connected industrial sensor hub: the 10-bit ADC digitizes analog sensors while the msCAN reports filtered readings on a 250 kbps bus. With 256 KB Flash, ample room remains for sensor linearization curves, digital filters, and a CANopen-style object dictionary. Operating from -40C to +125C allows deployment near motors and hydraulic actuators. The 25 MHz HCS12 core provides enough headroom for floating-point math and dual-axis sensor fusion without an external DSP. Place a CAN transceiver such as TJA1040 within 50 mm of the CAN pins to keep the differential pair matched at 100 ohm and meet IEC 61000-4-2 ESD on the bus.
Recommended
HVAC Climate Control Unit
Climate-control units benefit from the MC9S12B256MFUE because the PWM module drives blower motors and stepper valves directly, while the ADC reads thermistor inputs for closed-loop temperature regulation. The 8-channel 8-bit PWM eliminates the need for a separate motor-driver MCU, and the on-chip EEPROM saves user-preference setpoints across power cycles. With a 2.35 V to 5.5 V supply range, the part survives cranking transients on 12 V automotive buses when paired with an external regulator. The Enhanced Capture Timer measures AC-line frequencies for 50/60 Hz hum rejection. Comparable in capability to dedicated HVAC MCUs, the B256 adds 256 KB Flash for graphical LCD menu code.
Recommended
LIN/CAN Gateway Bridge
Use the MC9S12B256MFUE as a low-cost LIN-to-CAN bridge for automotive network segments. The SCI1 channel pairs with a TJA1027 LIN transceiver, while the msCAN port sits on the chassis CAN backbone. With 256 KB Flash the part holds the full LIN 2.1 diagnostic stack and CAN transport layer simultaneously. The HCS12 core executes the translation table at sub-millisecond latency, faster than typical LIN frame deadlines. Compared with dedicated bridge ICs, the B256 gives firmware-upgrade capability and OEM-customizable node behaviors. Keep the LIN and CAN traces separated by a ground pour to limit cross-bus noise coupling.
Recommended
Battery Management Module (12V/24V Automotive)
For automotive battery monitoring, the MC9S12B256MFUE reads stack voltage, current shunt, and temperature sensors via its 10-bit ADC. The EEPROM stores battery aging parameters and SoH (state-of-health) history - 4 KB is enough for ~30 days of hourly logs. CAN connectivity streams SoC (state-of-charge) to the vehicle ECU. The wide 2.35 V to 5.5 V supply lets the part operate directly from a 12 V rail after a small LDO. Designers should verify the ADC's 10-bit precision across the -40C to +125C range; for higher accuracy consider the S12X derivatives with 12-bit ADC.
Recommended
Automotive Instrument Cluster Auxiliary MCU
The MC9S12B256MFUE sits as an auxiliary controller driving stepper-motor gauges and warning lamps in an instrument cluster. Each PWM channel controls a single analog gauge, and the ADC reads fuel-level sender and oil-pressure inputs. The 256 KB Flash stores graphic-segment rendering code and CAN diagnostic tables. Compared with discrete logic, this approach yields a single firmware build that scales across car models by changing lookup tables in Flash. The NRND lifecycle status means designers planning new cluster programs should pivot to S12ZVL or S32K families - the B256 remains viable for legacy platforms only.
Recommended
CAN-Connected Lighting Module
The MC9S12B256MFUE powers an automotive lighting module where the 8-channel PWM drives LED strings at 8-bit brightness per channel, and the msCAN bus receives lighting commands from the BCM. The 256 KB Flash contains the boot loader, LED thermal-folding algorithm, and CAN diagnostic handler. Operating junction temperature up to 125C supports under-hood placement. Compared with discrete 8-bit PWM expanders, the B256 reduces PCB area by roughly 60 percent. Pair each PWM output with an external MOSFET driver since the on-chip PWM is logic-level only and cannot sink incandescent bulb currents directly.
Recommended
Recommended Products Summary
Engineering reference data for MC9S12B256MFUE — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC9S12B128MFUE | MC9S12B512MFUE | MC9S12DT256MFUE | MC9S12XA256VAA |
|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 80-QFP 14x14 mm | 80-QFP 14x14 mm (same) | 80-QFP 14x14 mm (same) | 80-QFP 14x14 mm (same) | 80-QFP 14x14 mm (same) |
| Flash Memory | 256 KB | 128 KB (-50%) | 512 KB (+100%) | 256 KB (same) | 256 KB (same) |
| RAM | 12 KB | 8 KB | 16 KB | 12 KB | 12 KB |
| CPU Core | HCS12 16-bit | HCS12 16-bit | HCS12 16-bit | HCS12 16-bit | HCS12X 16-bit + XGate co-processor |
| Maximum CPU Clock | 25 MHz | 25 MHz | 25 MHz | 25 MHz | 40 MHz |
| CAN Controllers | 1 x msCAN | 1 x msCAN | 1 x msCAN | 2 x msCAN | 5 x msCAN |
| SCI / SPI / I2C | 1 / 1 / 1 | 1 / 1 / 1 | 1 / 1 / 1 | 2 / 1 / 1 | 2 / 1 / 1 |
| Lifecycle Status | NRND | NRND | NRND | NRND | Active |
Key Differentiators
- Largest Flash in the 80-QFP 14x14 S12B lineup with active CPU clock at 25 MHz (vs MC9S12B128MFUE)
- Pin-compatible upgrade path to dual-CAN with no PCB change (vs MC9S12DT256MFUE)
- Legacy-compatible HCS12 core without the XGate co-processor (vs MC9S12XA256VAA)
Design Notes
Place a 100 nF decoupling capacitor on every VDD/VSS pair (VDD1/SS1 through VDD4/SS4) within 5 mm of the pin. Add a single 10 uF bulk tantalum or ceramic at the supply entry point. The internal 2.5 V regulator requires a 1 uF low-ESR cap on VDDR (pin 1); failure to add this cap causes erratic PLL lock behavior. Total estimated decoupling budget: ~4 x 100 nF + 1 x 10 uF + 1 x 1 uF. Estimated total capacitor cost is approximately $0.20 per board at qty 1000.
Keep the XTAL/EXTAL traces short (under 10 mm) and surround them with a guarded ground channel. Place the crystal load capacitors within 5 mm of each pin and connect their common node to a quiet analog ground. If an external CMOS clock drives EXTAL, leave XTAL floating. For CAN-bus applications, route CAN-H/CAN-L as a 100 ohm differential pair, matching length within 5 mm, and keep the bus away from switching power traces by at least 3 mm. The 80-QFP 14x14 mm footprint allows generous creepage but still requires a ground pour under the package to reduce thermal resistance.
Do not connect the BKGD (Background Debug) pin to a push-pull driver; it uses an open-drain scheme with an internal pull-up. Reverse-engineered clone parts marked 9S12B256 are electrically similar but may disable the BDM lock command, allowing code extraction - always source from authorized distributors or directly from NXP. The NRND status on the NXP product page does not mean production has stopped - stock is still active as of 2026-10-21 - but new designs should evaluate S12Z or S32K derivatives.
Estimated: at 25 MHz CPU clock with all peripherals active and 5.0 V VDD, the MC9S12B256MFUE draws approximately 60 mA, dissipating ~300 mW. With a QFP-80 theta-JA of roughly 45 C/W on a 4-layer PCB with 1 oz copper, junction rise above 25 C ambient is ~13.5 C - well within the 125 C maximum. For tight enclosures above 85 C ambient, add thermal vias under the center pad and increase copper pour area. The part is specified for -40 C to +125 C junction operation per the verified NXP family data.
Compliance Information
RoHS compliant per NXP material declaration. Not AEC-Q100 qualified in this MPN suffix - for AEC-Q100 automotive-grade operation use the validated S12X/Q families. Halogen-free status not stated in the available data; set to unknown.
