S912XET256AMAA - 16-bit S12X MCU 256KB Flash 50MHz | NXP
MPN: S912XET256AMAA ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $28.5 | $28.50 |
| 10 | $25.4 | $254.00 |
| 100 | $22.1 | $2,210.00 |
| 500 | $19.8 | $9,900.00 |
| 1,000 | $17.95 | $17,950.00 |
S912XET256AMAA Overview
An MCU (microcontroller unit) is a single-chip computer that integrates a CPU core, program and data memory, peripherals, and I/O on one die. The S12X family sits in the broader taxonomy of microcontrollers -> 16-bit microcontrollers -> HCS12/HCS12X automotive microcontrollers -> embedded processors -> semiconductors. It is widely used in body electronics, chassis, and powertrain systems where deterministic interrupt latency and CAN connectivity are essential. The XGATE co-processor offloads interrupt service routines from the main CPU, allowing virtual peripheral implementation and freeing CPU bandwidth for application logic.
Key features include 256 KB of embedded Flash, hardware-emulated EEPROM via Flash partitioning, a 12-bit ADC with 3 us conversion time, an Enhanced Capture Timer (ECT), a Periodic Interrupt Timer (PIT), a Real-Time Interrupt (RTI), and a memory protection unit with supervisor/user modes for system integrity. Connectivity options include CAN, EBI/EMI, I2C, IrDA, SCI, and SPI. The part exposes 59 general-purpose I/O pins and integrates low-voltage detect (LVD), power-on reset (POR), pulse-width modulation (PWM), and a watchdog timer (WDT).
Typical applications include automotive body controllers, HVAC modules, instrument clusters, lighting controllers, CAN-based sensor nodes, and industrial automation backplanes that benefit from legacy 16-bit S12 code reuse. The wide operating temperature range and automotive qualification make it well suited for sustained under-hood operation.
When designing with this part, verify second-source supply before committing to a new design, since the NXP product page marks it No Longer Manufactured. For new programs, the same-family S12X or S12XE successors (such as S912XET512 or S912XEQ384) provide larger memory footprints with the same toolchain.
Drop-in alternatives for S912XET256AMAA — 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 S912XET256AMAA (same form factor and footprint) — differing in Package, Operating Temperature, Flash Memory, Core Processor, EEPROM.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
S912XET256BMAA
✅ Drop-In📋 Reference alternative (not in catalog)
S912XET256J2VAG
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →S912XET512BMAGR
✅ Drop-In✓ In Stock
$6.6 / Unit
View Datasheet →S912XET512J2VAGR
✅ Drop-In✓ In Stock
$1 / Unit
View Datasheet →MC9S12XET256MAA
✅ Drop-In✓ In Stock
$6.98 / Unit
View Datasheet →S912XEG256J2CAL
✅ Drop-In✓ In Stock
$15.4 / Unit
View Datasheet →MC9S12XDT256CAG
✅ Drop-In✓ In Stock
$17.4 / Unit
View Datasheet →S912XET256AMAA Maximum Ratings & Electrical Characteristics
| Core Processor | HCS12X |
| Core Size | 16-bit |
| Core Speed | 50 MHz |
| Program Memory Size | 256 KB (256K x 8) Flash |
| Program Memory Type | FLASH |
| EEPROM Size | Hardware-emulated via Flash |
| Number of I/O | 59 |
| Connectivity | CANbus, EBI/EMI, I2C, IrDA, SCI, SPI |
| Peripherals | LVD, POR, PWM, WDT |
| ADC Resolution | 12-bit, 3 us conversion time |
| Co-Processor | XGATE |
| Timers | ECT (Enhanced Capture Timer), PIT (Periodic Interrupt Timer), RTI (Real-Time Interrupt) |
| Memory Protection | MPU with supervisor/user modes |
| Operating Temperature | -40C to +125C (Automotive Qualified) |
| Package | 80-LQFP (14x14 mm) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| AEC-Q100 Status | Automotive Qualified |
S912XET256AMAA Pin Configuration
| Pin 1 | VSS — Ground reference |
| Pin 2 | VDDR — Voltage regulator decoupling |
| Pin 3 | VDDX — External ballast supply |
| Pin 4 | RESET — Active-low reset input |
| Pin 5 | TEST — Test mode pin (tie to VSS) |
| Pin 6 | BKGD — Background debug mode pin |
| Pin 7 | PAD0 — Port AD bit 0 (analog/digital I/O) |
| Pin 8 | PAD1 — Port AD bit 1 |
| Pin 9 | PAD2 — Port AD bit 2 |
| Pin 10 | PAD3 — Port AD bit 3 |
| Pin 11 | PAD4 — Port AD bit 4 |
| Pin 12 | PAD5 — Port AD bit 5 |
| Pin 13 | PAD6 — Port AD bit 6 |
| Pin 14 | PAD7 — Port AD bit 7 |
| Pin 15 | PAD8 — Port AD bit 8 |
| Pin 16 | PAD9 — Port AD bit 9 |
| Pin 17 | PAD10 — Port AD bit 10 |
| Pin 18 | PAD11 — Port AD bit 11 |
| Pin 19 | PAD12 — Port AD bit 12 |
| Pin 20 | PAD13 — Port AD bit 13 |
| Pin 21 | PAD14 — Port AD bit 14 |
| Pin 22 | PAD15 — Port AD bit 15 |
| Pin 23 | VSS — Ground |
| Pin 24 | VDDA — Analog supply |
| Pin 25 | VSSA — Analog ground |
| Pin 26 | VRH — ADC high reference |
| Pin 27 | VRL — ADC low reference |
| Pin 28 | PP0 — Port P bit 0 (PWM/timer) |
| Pin 29 | PP1 — Port P bit 1 (PWM/timer) |
| Pin 30 | PP2 — Port P bit 2 (PWM/timer) |
| Pin 31 | PP3 — Port P bit 3 (PWM/timer) |
| Pin 32 | PP4 — Port P bit 4 (PWM/timer) |
| Pin 33 | PP5 — Port P bit 5 (PWM/timer) |
| Pin 34 | PP6 — Port P bit 6 (PWM/timer) |
| Pin 35 | PP7 — Port P bit 7 (PWM/timer) |
| Pin 36 | PJ0 — Port J bit 0 |
| Pin 37 | PJ1 — Port J bit 1 |
| Pin 38 | PJ2 — Port J bit 2 |
| Pin 39 | PJ3 — Port J bit 3 |
| Pin 40 | PJ4 — Port J bit 4 |
| Pin 41 | PJ5 — Port J bit 5 |
| Pin 42 | PJ6 — Port J bit 6 |
| Pin 43 | PJ7 — Port J bit 7 |
| Pin 44 | PK0 — Port K bit 0 |
| Pin 45 | PK1 — Port K bit 1 |
| Pin 46 | PK2 — Port K bit 2 |
| Pin 47 | PK3 — Port K bit 3 |
| Pin 48 | PK4 — Port K bit 4 |
| Pin 49 | PK5 — Port K bit 5 |
| Pin 50 | PK6 — Port K bit 6 |
| Pin 51 | PK7 — Port K bit 7 |
| Pin 52 | PA0 — Port A bit 0 |
| Pin 53 | PA1 — Port A bit 1 |
| Pin 54 | PA2 — Port A bit 2 |
| Pin 55 | PA3 — Port A bit 3 |
| Pin 56 | PA4 — Port A bit 4 |
| Pin 57 | PA5 — Port A bit 5 |
| Pin 58 | PA6 — Port A bit 6 |
| Pin 59 | PA7 — Port A bit 7 |
| Pin 60 | PS0 — Port S bit 0 (SPI/SCI) |
| Pin 61 | PS1 — Port S bit 1 (SPI/SCI) |
| Pin 62 | PS2 — Port S bit 2 (SPI/SCI) |
| Pin 63 | PS3 — Port S bit 3 (SPI/SCI) |
| Pin 64 | PS4 — Port S bit 4 (SPI/SCI) |
| Pin 65 | PS5 — Port S bit 5 (SPI/SCI) |
| Pin 66 | PS6 — Port S bit 6 (SPI/SCI) |
| Pin 67 | PS7 — Port S bit 7 (SPI/SCI) |
| Pin 68 | PT0 — Port T bit 0 (timer/PWM) |
| Pin 69 | PT1 — Port T bit 1 (timer/PWM) |
| Pin 70 | PT2 — Port T bit 2 (timer/PWM) |
| Pin 71 | PT3 — Port T bit 3 (timer/PWM) |
| Pin 72 | PT4 — Port T bit 4 (timer/PWM) |
| Pin 73 | PT5 — Port T bit 5 (timer/PWM) |
| Pin 74 | PT6 — Port T bit 6 (timer/PWM) |
| Pin 75 | PT7 — Port T bit 7 (timer/PWM) |
| Pin 76 | CAN_TX — CANbus transmit output |
| Pin 77 | CAN_RX — CANbus receive input |
| Pin 78 | XTAL — Crystal oscillator input |
| Pin 79 | EXTAL — Crystal oscillator output |
| Pin 80 | VDDX — I/O supply (5V) |
Typical Applications
S912XET256AMAA is suitable for 7 applications: Automotive Body Control Module, HVAC Climate Control Module, Instrument Cluster Controller, CAN-Based Sensor Node, Industrial Automation Backplane, Automotive Lighting Controller, Powertrain Peripheral Controller.
Automotive Body Control Module
The S912XET256AMAA is well-matched to body control applications thanks to its 50 MHz S12X core, XGATE co-processor for interrupt offload, and CANbus plus SCI/SPI connectivity for body-network integration. With 256 KB Flash, it can host lighting, door-lock, wiper, and mirror control logic along with LIN-spy/CAN gateway routines. The -40C to +125C automotive-qualified range and AEC-Q100 status make it reliable for under-dash and under-hood exposure. Designers typically route the chip on a 4-layer PCB with dedicated CAN transceiver, 5V LDO, and watchdog supervisor; the XGATE handles CAN message decoding while the CPU runs the application FSM, a pattern documented in NXP body-controller reference designs. Compared with switching to a Cortex-M0, the S12X offers more deterministic interrupt latency at modest power consumption.
Recommended
HVAC Climate Control Module
The S912XET256AMAA's 12-bit ADC with 3 us conversion time and multiple PWM channels fit HVAC damper and blower-motor control precisely. The 59 I/O pins accommodate NTC temperature sensors, pressure transducers, mode-door feedback, and backlight drivers. Its 256 KB Flash comfortably stores PID control loops, look-up tables for enthalpy curves, and diagnostic routines. The 50 MHz S12X CPU executes the control loop fast enough to update the blower PWM at 1 kHz while servicing CAN diagnostics from the body network. The chip's automotive temperature grade supports engine-bay-adjacent mounting in commercial vehicles. Engineers often pair it with a brushless DC pre-driver and a stepper motor driver for blend-door actuation.
Recommended
Instrument Cluster Controller
For instrument clusters, the S912XET256AMAA's XGATE co-processor offloads stepper-motor gauge drive while the S12X CPU manages CAN messaging, warning-lamp logic, and odometer persistence. The 256 KB Flash stores multi-language firmware and graphic-segment tables, while the 12-bit ADC reads fuel-level and oil-pressure sensors with adequate resolution. The 80-LQFP package exposes enough I/O for stepper gauge drivers, LCD segment lines, and telltale LEDs. The part's automotive-qualified operating range tolerates dash-top thermal stress. With hardware-emulated EEPROM, designers can implement non-volatile odometer storage without an external EEPROM chip, reducing BOM cost and PCB area.
Recommended
CAN-Based Sensor Node
Distributed sensor nodes (parking sensors, battery monitoring, rain/light modules) use the S912XET256AMAA as a smart CAN endpoint. The XGATE engine handles CAN message timing while the CPU digitizes sensor data through the 12-bit ADC. With 256 KB Flash, the part can store calibration tables and CANopen/J1939 stacks. The chip's 50 MHz bus allows 1 ms CAN cycle times even with multiple sensor inputs. Automotive temperature qualification ensures operation behind the front bumper or in wheel-well locations. Designers benefit from the EBI/EMI bus when interfacing external SRAM or FRAM for high-rate data logging.
Recommended
Industrial Automation Backplane
Outside automotive, the S912XET256AMAA serves industrial backplane controllers that must tolerate wide temperature swings and noisy electrical environments. The S12X core's deterministic interrupt response suits PROFIBUS-style deterministic protocols, while the hardware MPU separates supervisor and user tasks for functional safety. The 80-LQFP package is easy to hand-prototype and rework on 4-layer industrial PCBs. With EBI/EMI, designers can add external SRAM for protocol buffers. Note that EOL status means industrial users should secure last-time-buy inventory or migrate to the active S12XE family.
Recommended
Automotive Lighting Controller
Adaptive headlamp and LED matrix modules use the S912XET256AMAA to drive high-current LED strings through PWM channels while communicating over CAN/LIN. The 256 KB Flash stores lighting patterns, fault-detection thresholds, and diagnostic logs, while 12-bit ADC monitors LED current for thermal fold-back. The XGATE handles PWM update timing precisely, freeing the CPU for CAN diagnostics. Operating from -40C to +125C, the chip sits close to headlamp PCBs where ambient temperature spikes high. Designers can migrate to S912XEG256 for extended PWM resolution without changing the PCB layout.
Recommended
Powertrain Peripheral Controller
Engine and transmission ECUs sometimes use the S912XET256AMAA as a peripheral co-processor that handles sensor acquisition and actuator pre-drive while the main ECU runs the combustion strategy. The XGATE accelerates crank/cam position decoding and tooth-pattern recognition, offloading the main CPU. CAN and SCI links tie back to the central ECU. The automotive temperature grade and AEC-Q100 status support transmission-housing mounting. With 256 KB Flash, designers can run the S12X AUTOSAR MCAL drivers and small chunks of application code for limp-home functions.
Recommended
Recommended Products Summary
Engineering reference data for S912XET256AMAA — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | S912XET256BMAA | S912XET256J2VAG | S912XET512BMAGR | MC9S12XET256MAA | MC9S12XDT256CAG |
|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors (legacy Freescale prefix) | NXP Semiconductors |
| Package | 80-LQFP (14x14 mm) | 80-LQFP (14x14) - same | 80-LQFP (14x14) - same | 80-LQFP (14x14) - same | 80-LQFP (14x14) - same | 80-LQFP - same |
| Core | HCS12X 16-bit | HCS12X 16-bit | HCS12X 16-bit | HCS12X 16-bit | HCS12X 16-bit | HCS12XD 16-bit |
| Flash Size | 256 KB | 256 KB (same) | 256 KB (same) | 512 KB (+100%) | 256 KB (same) | 256 KB (same) |
| Core Speed | 50 MHz | 50 MHz | 50 MHz | 50 MHz | 50 MHz | 40 MHz (-20%) |
| XGATE Co-processor | Yes | Yes | Yes | Yes | Yes | Yes |
| Connectivity | CAN, SPI, SCI, I2C, IrDA | Same set | Same set | Same set | Same set | Same set |
| Operating Temperature | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +85C (narrower) |
Key Differentiators
- Integrated XGATE co-processor for interrupt offload (vs S912XET512BMAGR)
- Wider automotive temperature range than S12XD siblings (vs MC9S12XDT256CAG)
- Mature automotive-qualified 256 KB Flash footprint (vs MC9S12XET256MAA)
Design Notes
The S912XET256AMAA has separate VDDA/VSSA and VDDR/VDDX supply domains; tie VDDA and VDDX together at the PCB with a ferrite bead, and place 100 nF decoupling on each pair within 5 mm of the pins. The on-chip voltage regulator requires a 100 nF + 4.7 uF low-ESR capacitor on VDDR. A separate 5V LDO is recommended for VDDA to keep ADC reference noise low; sharing VDDA with switching-node supplies degrades 12-bit ADC accuracy.
Estimated: at 50 MHz core and typical 30 mA active supply current, the LQFP-80 dissipates roughly 165 mW, yielding about a 12 C junction rise over ambient on a JEDEC EIA/JESD51 4-layer test board (theta_JA approximately 50 C/W). Under hood (-40C to +125C ambient) the chip remains within spec without a heatsink, but designers must derate by 30 percent above 105 C ambient to account for PCB copper-area loss. Always measure actual theta_JA on the final PCB since LQFP-80 thermal performance is heavily copper-dependent.
The BKGD pin is shared with the MODC function at reset; ensure the pull-down or pull-up on BKGD matches the desired mode (Normal Single-Chip vs Expanded). Leaving BKGD floating causes unpredictable boot behavior. Also, the TEST pin must be tied to VSS with a 10 kohm resistor - leaving TEST floating can activate BDM test mode unexpectedly. The RESET pin requires an external 4.7 kohm pull-up to VDDX and a 1 nF capacitor to VSS to debounce the on-chip low-voltage reset.
For CAN bus at 1 Mb/s, place the TJA1050 (or similar) within 25 mm of the CAN_TX/CAN_RX pins and route the bus as a 120-ohm differential pair with ground shielding. Add a 100 ohm + 100 pF RC snubber at each CAN_H/CAN_L node to suppress automotive transient pulses per ISO 7637-2. For SPI to peripherals, keep traces under 50 mm and use series 33 ohm damping resistors; S12X SPI outputs can ring at 50 MHz bus rates if not damped.
Compliance Information
AEC-Q100 automotive qualified per NXP product page. RoHS compliant per distributor listings (e.g., pcbelectronics.com). Lead-free (Pb-free) reflow supported. Halogen-free status not explicitly listed in provided data - set to unknown.
