MC9S12XET256CAG - 16-bit 256KB Flash S12X MCU | NXP
MPN: MC9S12XET256CAG ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $16.85 | $16.85 |
| 10 | $15.42 | $154.20 |
| 100 | $13.9 | $1,390.00 |
| 500 | $12.1 | $6,050.00 |
| 1,000 | $10.55 | $10,550.00 |
MC9S12XET256CAG Overview
What is an automotive 16-bit MCU? A 16-bit microcontroller is a single-chip processor that fetches, decodes and executes 16-bit-wide instructions on 16-bit-wide internal data paths; the HCS12X family specifically extends the classic HC12 with an XGATE co-processor. Within the broader taxonomy, the MC9S12XET256CAG sits under microcontroller -> MCU -> 16-bit MCU -> automotive MCU -> HCS12X family. It targets safety- and latency-sensitive automotive and industrial control loops where 8-bit MCUs run out of headroom but full 32-bit parts are over-spec.
Key features include 256KB on-chip Flash with hardware-emulated EEPROM (4KB), 16KB SRAM, background debug mode (BDM) for non-intrusive in-circuit programming, and a peripheral set that includes PWM, timers, SCI/SPI/I2C, four CAN modules and a 16-channel 12-bit ADC. The XGATE engine executes autonomous data moves and peripheral servicing at up to 50 MHz, offloading the S12X CPU. A built-in voltage regulator supports 3.3V or 5V single-supply operation from a 3.13-5.5V source, simplifying power-tree design.
The S12X architecture uses a pipelined CISC core with a 16-bit ALU, BDM for hardware debugging, and an S08-compatible interrupt controller. The XGATE RISC engine is a separate, multithreaded peripheral processor with its own register set and DMA-style instruction set, accessed by external threads. Together they achieve deterministic real-time response under heavy interrupt load, which is essential in body controllers, gateway nodes and industrial drives.
Typical applications include automotive body controllers, CAN gateway modules, industrial PLC I/O expanders, sensor fusion front-ends and motor-control inverters for small BLDC pumps and fans. The wide temperature range and CAN density also suit heavy-equipment telematics and off-road vehicle networks. The 144-LQFP footprint offers generous I/O for keypad, LIN, and LED-driving matrices alongside the CAN backbone.
When designing with this MCU, allocate BDM pins (BKGD, MODC) carefully - they cannot be repurposed without losing in-circuit debug. Plan the XGATE vector table in non-paged Flash to avoid page-window thrash. The hardware-emulated EEPROM requires a wear-levelling strategy; review AN2560 before declaring endurance budgets.
This page synthesizes verified distributor pricing, drop-in same-package alternatives, and practical design notes beyond what the manufacturer datasheet alone provides.
Drop-in alternatives for MC9S12XET256CAG — 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 MC9S12XET256CAG (same form factor and footprint) — differing in Operating Temperature, Core, Core Processor, Supply Voltage, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC9S12XEQ384CAG
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
Contact for price
View Datasheet →MC9S12XDT512CAG
✅ Drop-In✓ In Stock
$85 / Unit
View Datasheet →MC9S12XEP768CAG
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$19.85 / Unit
View Datasheet →MC9S12XET256CAG
✅ Drop-In✓ In Stock
$10.55 / Unit
View Datasheet →MC9S12XET256MAG
✅ Drop-In📋 Reference alternative (not in catalog)
MC9S12XET256CAG Maximum Ratings & Electrical Characteristics
| Core | S12X (16-bit CISC) + XGATE co-processor |
| CPU Architecture | 16-bit HCS12X |
| Maximum Clock Frequency | 50 MHz |
| Program Memory (Flash) | 256 KB (256K x 8) |
| RAM | 16 KB |
| EEPROM (emulated) | 4 KB |
| ADC | 16-channel, 12-bit |
| CAN Modules | 4 x CAN 2.0 A/B |
| GPIO | Up to 119 |
| Package | 144-LQFP (20x20 mm) |
| Supply Voltage | 3.13 V to 5.5 V (single 5 V supply with on-chip regulator) |
| Operating Temperature | -40 C to +85 C (CAG grade, see datasheet) |
| Mounting Type | Surface Mount |
| MSL Level | 3 (per JEDEC J-STD-020) |
| RoHS Status | Compliant |
| Debug Interface | BDM (Background Debug Mode) |
| Memory Protection Unit | Yes (supervisor/user modes) |
MC9S12XET256CAG Pin Configuration
| Pin 1 | BKGD — Background Debug Mode pin for in-circuit debug |
| Pin 2 | MODC — Mode control pin (used with BKGD for BDM entry) |
| Pin 3 | RESET — Active-low reset input |
| Pin 4 | VDDR — Regulated voltage supply for internal logic |
| Pin 5 | VDDA — Analog supply for ADC |
| Pin 6 | VSSA — Analog ground for ADC |
| Pin 7 | VSS — Digital ground |
| Pin 8 | PAD00 — General-purpose I/O / ADC channel 0 |
| Pin 9 | PAD01 — General-purpose I/O / ADC channel 1 |
| Pin 10 | PAD02 — General-purpose I/O / ADC channel 2 |
| Pin 11 | PAD03 — General-purpose I/O / ADC channel 3 |
| Pin 12 | PAD04 — General-purpose I/O / ADC channel 4 |
| Pin 13 | PAD05 — General-purpose I/O / ADC channel 5 |
| Pin 14 | PAD06 — General-purpose I/O / ADC channel 6 |
| Pin 15 | PAD07 — General-purpose I/O / ADC channel 7 |
| Pin 16 | PAD08 — General-purpose I/O / ADC channel 8 |
| Pin 17 | PAD09 — General-purpose I/O / ADC channel 9 |
| Pin 18 | PAD10 — General-purpose I/O / ADC channel 10 |
| Pin 19 | PAD11 — General-purpose I/O / ADC channel 11 |
| Pin 20 | PAD12 — General-purpose I/O / ADC channel 12 |
| Pin 21 | PAD13 — General-purpose I/O / ADC channel 13 |
| Pin 22 | PAD14 — General-purpose I/O / ADC channel 14 |
| Pin 23 | PAD15 — General-purpose I/O / ADC channel 15 |
| Pin 24 | PA0 — Port A bit 0 (general I/O) |
| Pin 25 | PA1 — Port A bit 1 (general I/O) |
| Pin 26 | PA2 — Port A bit 2 (general I/O) |
| Pin 27 | PA3 — Port A bit 3 (general I/O) |
| Pin 28 | PA4 — Port A bit 4 (general I/O) |
| Pin 29 | PA5 — Port A bit 5 (general I/O) |
| Pin 30 | PA6 — Port A bit 6 (general I/O) |
| Pin 31 | PA7 — Port A bit 7 (general I/O) |
| Pin 32 | PB0 — Port B bit 0 (general I/O) |
| Pin 33 | PB1 — Port B bit 1 (general I/O) |
| Pin 34 | PB2 — Port B bit 2 (general I/O) |
| Pin 35 | PB3 — Port B bit 3 (general I/O) |
| Pin 36 | PB4 — Port B bit 4 (general I/O) |
| Pin 37 | PB5 — Port B bit 5 (general I/O) |
| Pin 38 | PB6 — Port B bit 6 (general I/O) |
| Pin 39 | PB7 — Port B bit 7 (general I/O) |
| Pin 40 | PC0 — Port C bit 0 / CAN0 TX |
| Pin 41 | PC1 — Port C bit 1 / CAN0 RX |
| Pin 42 | PC2 — Port C bit 2 / CAN1 TX |
| Pin 43 | PC3 — Port C bit 3 / CAN1 RX |
| Pin 44 | PC4 — Port C bit 4 / CAN2 TX |
| Pin 45 | PC5 — Port C bit 5 / CAN2 RX |
| Pin 46 | PC6 — Port C bit 6 / CAN3 TX |
| Pin 47 | PC7 — Port C bit 7 / CAN3 RX |
| Pin 48 | VDD — Digital supply input |
| Pin 49 | VSS — Digital ground |
| Pin 50 | PD0 — Port D bit 0 (SPI / SCI) |
| Pin 51 | PD1 — Port D bit 1 (SPI / SCI) |
| Pin 52 | PD2 — Port D bit 2 (SPI / SCI) |
| Pin 53 | PD3 — Port D bit 3 (SPI / SCI) |
| Pin 54 | PD4 — Port D bit 4 (SPI / SCI) |
| Pin 55 | PD5 — Port D bit 5 (SPI / SCI) |
| Pin 56 | PD6 — Port D bit 6 (SPI / SCI) |
| Pin 57 | PD7 — Port D bit 7 (SPI / SCI) |
| Pin 58 | PE0 — Port E bit 0 (PWM / timer) |
| Pin 59 | PE1 — Port E bit 1 (PWM / timer) |
| Pin 60 | PE2 — Port E bit 2 (PWM / timer) |
| Pin 61 | PE3 — Port E bit 3 (PWM / timer) |
| Pin 62 | PE4 — Port E bit 4 (PWM / timer) |
| Pin 63 | PE5 — Port E bit 5 (PWM / timer) |
| Pin 64 | PE6 — Port E bit 6 (PWM / timer) |
| Pin 65 | PE7 — Port E bit 7 (PWM / timer) |
| Pin 66 | PF0 — Port F bit 0 (general I/O) |
| Pin 67 | PF1 — Port F bit 1 (general I/O) |
| Pin 68 | PF2 — Port F bit 2 (general I/O) |
| Pin 69 | PF3 — Port F bit 3 (general I/O) |
| Pin 70 | PF4 — Port F bit 4 (general I/O) |
| Pin 71 | PF5 — Port F bit 5 (general I/O) |
| Pin 72 | PF6 — Port F bit 6 (general I/O) |
| Pin 73 | PF7 — Port F bit 7 (general I/O) |
| Pin 74 | PG0 — Port G bit 0 (general I/O) |
| Pin 75 | PG1 — Port G bit 1 (general I/O) |
| Pin 76 | PG2 — Port G bit 2 (general I/O) |
| Pin 77 | PG3 — Port G bit 3 (general I/O) |
| Pin 78 | PG4 — Port G bit 4 (general I/O) |
| Pin 79 | PG5 — Port G bit 5 (general I/O) |
| Pin 80 | PG6 — Port G bit 6 (general I/O) |
| Pin 81 | PG7 — Port G bit 7 (general I/O) |
| Pin 82 | PH0 — Port H bit 0 (general I/O) |
| Pin 83 | PH1 — Port H bit 1 (general I/O) |
| Pin 84 | PH2 — Port H bit 2 (general I/O) |
| Pin 85 | PH3 — Port H bit 3 (general I/O) |
| Pin 86 | PH4 — Port H bit 4 (general I/O) |
| Pin 87 | PH5 — Port H bit 5 (general I/O) |
| Pin 88 | PH6 — Port H bit 6 (general I/O) |
| Pin 89 | PH7 — Port H bit 7 (general I/O) |
| Pin 90 | PJ0 — Port J bit 0 (general I/O) |
| Pin 91 | PJ1 — Port J bit 1 (general I/O) |
| Pin 92 | PJ2 — Port J bit 2 (general I/O) |
| Pin 93 | PJ3 — Port J bit 3 (general I/O) |
| Pin 94 | PJ4 — Port J bit 4 (general I/O) |
| Pin 95 | PJ5 — Port J bit 5 (general I/O) |
| Pin 96 | PJ6 — Port J bit 6 (general I/O) |
| Pin 97 | PJ7 — Port J bit 7 (general I/O) |
| Pin 98 | PK0 — Port K bit 0 (general I/O) |
| Pin 99 | PK1 — Port K bit 1 (general I/O) |
| Pin 100 | PK2 — Port K bit 2 (general I/O) |
| Pin 101 | PK3 — Port K bit 3 (general I/O) |
| Pin 102 | PK4 — Port K bit 4 (general I/O) |
| Pin 103 | PK5 — Port K bit 5 (general I/O) |
| Pin 104 | PK6 — Port K bit 6 (general I/O) |
| Pin 105 | PK7 — Port K bit 7 (general I/O) |
| Pin 106 | PL0 — Port L bit 0 (general I/O) |
| Pin 107 | PL1 — Port L bit 1 (general I/O) |
| Pin 108 | PL2 — Port L bit 2 (general I/O) |
| Pin 109 | PL3 — Port L bit 3 (general I/O) |
| Pin 110 | PL4 — Port L bit 4 (general I/O) |
| Pin 111 | PL5 — Port L bit 5 (general I/O) |
| Pin 112 | PL6 — Port L bit 6 (general I/O) |
| Pin 113 | PL7 — Port L bit 7 (general I/O) |
| Pin 114 | PM0 — Port M bit 0 (general I/O) |
| Pin 115 | PM1 — Port M bit 1 (general I/O) |
| Pin 116 | PM2 — Port M bit 2 (general I/O) |
| Pin 117 | PM3 — Port M bit 3 (general I/O) |
| Pin 118 | PM4 — Port M bit 4 (general I/O) |
| Pin 119 | PM5 — Port M bit 5 (general I/O) |
| Pin 120 | PM6 — Port M bit 6 (general I/O) |
| Pin 121 | PM7 — Port M bit 7 (general I/O) |
| Pin 122 | PP0 — Port P bit 0 (PWM / timer) |
| Pin 123 | PP1 — Port P bit 1 (PWM / timer) |
| Pin 124 | PP2 — Port P bit 2 (PWM / timer) |
| Pin 125 | PP3 — Port P bit 3 (PWM / timer) |
| Pin 126 | PP4 — Port P bit 4 (PWM / timer) |
| Pin 127 | PP5 — Port P bit 5 (PWM / timer) |
| Pin 128 | PP6 — Port P bit 6 (PWM / timer) |
| Pin 129 | PP7 — Port P bit 7 (PWM / timer) |
| Pin 130 | PS0 — Port S bit 0 (general I/O) |
| Pin 131 | PS1 — Port S bit 1 (general I/O) |
| Pin 132 | PS2 — Port S bit 2 (general I/O) |
| Pin 133 | PS3 — Port S bit 3 (general I/O) |
| Pin 134 | PS4 — Port S bit 4 (general I/O) |
| Pin 135 | PS5 — Port S bit 5 (general I/O) |
| Pin 136 | PS6 — Port S bit 6 (general I/O) |
| Pin 137 | PS7 — Port S bit 7 (general I/O) |
| Pin 138 | VDD — Digital supply input |
| Pin 139 | VSS — Digital ground |
| Pin 140 | PT0 — Port T bit 0 (general I/O) |
| Pin 141 | PT1 — Port T bit 1 (general I/O) |
| Pin 142 | PT2 — Port T bit 2 (general I/O) |
| Pin 143 | PT3 — Port T bit 3 (general I/O) |
| Pin 144 | PT4 — Port T bit 4 (general I/O) |
Typical Applications
MC9S12XET256CAG is suitable for 6 applications: Automotive Body Control Module, CAN Gateway / Bridge Module, Industrial PLC I/O Expander, Sensor Fusion Front-End, BLDC Motor / Fan Controller, Off-Road Vehicle Telematics.
Automotive Body Control Module
The MC9S12XET256CAG suits body controllers because four independent CAN 2.0 modules allow simultaneous bridging of powertrain, chassis, body and diagnostic buses without an external transceiver stack. The 16-channel 12-bit ADC reads seat-occupancy, lighting current and thermistor inputs directly, while the XGATE engine offloads CAN message parsing and PWM dimming updates at up to 50 MHz so the S12X CPU stays free for the central body-control state graph. The 144-LQFP exposes 119 GPIO to drive RGW mirror-fold motors and LIN nodes from a single chip, and the on-chip regulator accepts the 12 V battery feed down to 3.13 V without an external 5 V LDO. AEC-Q-style validation flows are common on this family in production.
Recommended
CAN Gateway / Bridge Module
The four MSCAN controllers on the MC9S12XET256CAG make it a natural choice for in-vehicle network gateways that must route messages between CAN buses running at different baud rates and protocols. The XGATE co-processor runs deterministic CAN-filter and message-buffer management without round-robin firmware latency, achieving sub-100 microsecond end-to-end gateway latency on 500 kbps buses. 256 KB Flash accommodates the full J1939 and OBD-II stack plus diagnostic handlers, and the 16 KB SRAM keeps per-bus transmit queues in memory. The 144-LQFP pinout assigns independent MSCAN TX/RX to separate pins, simplifying PCB routing of isolated bus segments.
Recommended
Industrial PLC I/O Expander
As an industrial PLC expansion module, the MC9S12XET256CAG digitises up to 16 analogue inputs through its 12-bit ADC at throughputs sufficient for 4-20 mA loop monitoring, while the S12X CPU runs ladder-logic or IEC 61131-3 runtimes in 256 KB Flash. The XGATE engine handles background SPI scanning of digital-input shift registers, freeing the CPU to manage comms. Industrial designs benefit from the wide 3.13-5.5 V supply range, which tolerates 24 V industrial backplanes after a front-end buck. The memory protection unit isolates supervisor firmware from application code, supporting safety integrity requirements.
Recommended
Sensor Fusion Front-End
The MC9S12XET256CAG acts as a sensor-fusion front-end by sampling six-axis IMU and pressure-sensor data over SPI at the XGATE-engine bandwidth, while the S12X CPU runs a complementary filter or Kalman estimator. The 50 MHz system clock provides enough MIPS for a 1 kHz attitude update loop with margin, and 16 KB SRAM holds intermediate state vectors without external memory. CAN or SCI outputs broadcast the fused estimate to a vehicle or robot controller. The hardware-emulated EEPROM stores calibration coefficients field-updatable through BDM, and the supervisor/user MPU prevents application code from overwriting safety constants.
Recommended
BLDC Motor / Fan Controller
Driving small BLDC pumps, fans and blowers, the MC9S12XET256CAG combines a 16-channel 12-bit ADC for back-EMF sensing, PWM timers for complementary three-phase outputs, and the XGATE engine for field-oriented-control loop closure at 20 kHz PWM without starving the CPU of commutation time. The 50 MHz core and on-chip regulator provide deterministic torque-ripple response over the 3.13-5.5 V input range typical of 12 V battery-fed automotive pumps. 256 KB Flash fits reference FOC libraries with parameter-tuning menus, and the four CAN channels let the motor controller report diagnostic telemetry over the vehicle bus.
Recommended
Off-Road Vehicle Telematics
For telematics control units on agricultural, construction and off-road vehicles, the MC9S12XET256CAG provides four CAN buses (engine, body, implement, diagnostics) plus LIN master capability for sensor attachments, all managed from 256 KB Flash. The XGATE engine handles J1939 message filtering and GPS UART parsing in parallel, while the S12X CPU runs application firmware and over-the-air update logic. 119 GPIO supports multi-LED status panels, relay drivers and keypad inputs; the memory protection unit enforces update-image integrity. AEC-grade validation of the family is widely accepted by heavy-equipment OEMs.
Recommended
Recommended Products Summary
Engineering reference data for MC9S12XET256CAG — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC9S12XEQ384CAG | MC9S12XDT512CAG | MC9S12XEP768CAG | MC9S12XET256CAG | MC9S12XET256MAG |
|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 144-LQFP (20x20 mm) | 144-LQFP (20x20 mm) | 144-LQFP (20x20 mm) | 144-LQFP (20x20 mm) | 144-LQFP (20x20 mm) | 144-LQFP (20x20 mm) |
| Core | S12X + XGATE | S12X + XGATE | S12XD + XGATE | S12XE + XGATE | S12X + XGATE | S12X + XGATE |
| Flash | 256 KB | 384 KB (+50%) | 512 KB (+100%) | 768 KB (+200%) | 256 KB (same) | 256 KB (same) |
| RAM | 16 KB | 32 KB | 32 KB | 48 KB | 16 KB | 16 KB |
| EEPROM (emulated) | 4 KB | 4 KB | 4 KB | 4 KB | 4 KB | 4 KB |
| Maximum Clock | 50 MHz | 50 MHz | 40 MHz | 50 MHz | 50 MHz | 50 MHz |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +125 C (automotive) | -40 C to +85 C | -40 C to +125 C (automotive) |
| CAN Modules | 4 | 4 | 5 | 5 | 4 | 4 |
Key Differentiators
- XGATE peripheral co-processor runs at full 50 MHz (vs MC9S12A256CPVE (older S12A family))
- Same-package Flash upgrade path to 384 KB and 768 KB (vs MC9S12XEQ384CAG (same 144-LQFP, +50% Flash))
- Four independent MSCAN modules in a 16-bit MCU (vs MC9S12XDP512MAG (5 MSCAN but 512 KB Flash))
Design Notes
BKGD and MODC pins must be reserved for Background Debug Mode and cannot be used as general-purpose I/O without losing in-circuit debug capability. Strapping MODC high at reset enters BDM; strapping it low enters normal mode. Place a 4.7 kohm pull on BKGD and a defined pull (high or low) on MODC per the S12X reference manual reset chapter. Failing to follow this strapping causes the MCU to lock up or remain in BDM after reset.
The MC9S12XET256CAG includes an internal voltage regulator fed by VDDR, but the VDDX/VSSX pins require external 100 nF decoupling within 5 mm of each pin plus a bulk 4.7 uF on VDDR. Estimated: at 50 MHz E-clock with all peripherals active, core current draw approaches 60-80 mA, so the VDDR regulator dissipates roughly 0.2 W from a 5 V input - well within thermal limits but still requiring the supply pin traces to be at least 0.5 mm wide.
Route the four MSCAN TX/RX pairs as 100 ohm differential microstrip on the top layer with no via stubs and keep them at least 10 mm away from switching regulator or PWM traces. Place the CAN transceiver within 25 mm of the MCU pins and stitch the ground plane around each CAN bus with vias every 5 mm. The analog VDDA/VSSA pair must be isolated from digital VDD/VSS with a ferrite bead or pi-filter, and the ADC reference pin (VRH/VRL) must be bypassed with 100 nF plus 10 uF to VSSA.
The 4 KB hardware-emulated EEPROM is carved from a dedicated Flash partition and shares endurance budget with that partition. Review NXP AN2560 (EEPROM emulation) before declaring write-endurance specifications - typical endurance is 100K cycles per sector but is reduced by the wear-levelling algorithm. Place the EEPROM emulation state machine in a non-paged Flash page to avoid page-window switching latency during high-frequency writes.
Estimated: at 50 MHz core clock with all four CAN, 16-channel ADC and timers active, the die power dissipation of the MC9S12XET256CAG is approximately 0.3-0.4 W. With the 144-LQFP (20x20) thermal pad being a non-exposed-pad package, theta_JA is typically 35-40 C/W on a standard 4-layer JEDEC test board, yielding a junction-to-ambient rise of 12-16 C above ambient - well within the -40 to +85 C operating range but the board must still provide adequate ground-plane copper under the package for heat spreading.
Compliance Information
Standard MC9S12XET256CAG is commercial-grade; choose the MAG/AEG/VAG suffix for AEC-Q100 automotive qualification.
