MC908MR32CBE - 8-Bit HC08MR MCU 32KB Flash 5V | NXP
MPN: MC908MR32CBE ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $11.8352 | $11.84 |
| 10 | $10.85 | $108.50 |
| 100 | $9.5 | $950.00 |
| 500 | $8.4 | $4,200.00 |
| 1,000 | $7.25 | $7,250.00 |
MC908MR32CBE Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, memory (Flash/RAM), and peripherals (timers, ADC, PWM, communication ports) onto one IC. The HC08 family is NXP's 8-bit CISC architecture, optimized for low-cost, deterministic embedded control. The HC08MR sub-family specifically adds a 6-channel 12-bit PWM (with programmable dead-time insertion) and a 10-bit ADC, placing it in the "Motor Control Power Management MCU" tier of the 8-bit controller hierarchy: HC08 < HC08MR < 8-bit MCU < microcontroller < embedded processor < semiconductor.
Key features include 32KB Flash organized as 32K x 8, 768B RAM, on-chip In-Circuit Programming (FLASHplus) via a single-wire background debug interface, low-voltage reset (LVR), and a clock generator module supporting crystal or internal bus operation. The wide 5V supply tolerance makes it well suited to industrial motor drives and appliance controls powered directly from rectified mains-derived rails. Per the HC08MR series datasheet, the part retains the classic HC08 instruction set for code compatibility with the broader M68HC05/M68HC08 family migration path.
Architecturally, the MC908MR32CBE uses the HC08 CPU core with a 16-bit index register and stack pointer, a sophisticated 12-bit PWM generator with edge- and center-aligned modes, and a 12-channel 10-bit successive-approximation ADC. The integrated fault-input and dead-time logic simplify three-phase inverter firmware, and dual high-current output pins (up to 10 mA) ease interface to gate-driver optocouplers. Mask-set revisions are documented in the MC68HC908MR32 Rev. 6.1 datasheet shipped on the NXP documents server.
Typical applications include washing-machine and dishwasher motor drives, ceiling-fan and small industrial inverters, switch-mode power-supply primary-side controllers, and white-goods appliance control boards. It also appears in low-cost fan pumps and hobby BLDC motor controllers where 8-bit determinism and integrated PWM outweigh the need for an ARM Cortex core. The part's wide 5V rail and 56-pin PSDIP footprint remain attractive for through-hole serviceable designs.
Designers should plan for a bypass capacitor network (typically a 100 nF ceramic plus an optional bulk electrolytic) within a few millimeters of the VDD pins, route the PWM outputs symmetrically to preserve dead-time accuracy, and ensure that programming/debug pins (IRQ, BKGD) are accessible for in-circuit firmware updates. Withdrawing mains-side 5V derived supplies must hold above 4.5V to avoid a brown-out reset during motor ramp.
This page synthesizes verified distributor data, drop-in compatible NXP/Freescale pin-to-pin alternatives, and design notes that go beyond the raw datasheet presentation, helping engineers select the right HC08MR device for production.
Drop-in alternatives for MC908MR32CBE — 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 MC908MR32CBE (same form factor and footprint) — differing in Program Memory Size, Supply Voltage, Core, Package / Case, RAM Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC908MR16CBE
✅ Drop-In✓ In Stock
$5.05 / Unit
View Datasheet →MC908MR32CBE Maximum Ratings & Electrical Characteristics
| Core | HC08 (8-bit CISC) |
| Processor Series | HC08MR |
| Data Bus Width | 8 bit |
| Maximum Clock Frequency | 8 MHz |
| Program Memory Size | 32 KB (32K x 8) Flash |
| RAM Size | 768 B |
| PWM Channels | 6 x 12-bit (with dead-time insertion) |
| ADC | 10-bit, 12 channels |
| Supply Voltage (Min) | 4.5 V |
| Supply Voltage (Max) | 5.5 V |
| Operating Temperature Range | -40C to +85C |
| Package / Case | 56-PSDIP (0.600", 15.24 mm) |
| Mounting Style | Through Hole |
| Number of ADC Channels | 12 |
MC908MR32CBE Pin Configuration
| Pin 1 | PTF0/TCH0 — Port F bit 0 / Timer Channel 0 |
| Pin 2 | PTF1/TCH1 — Port F bit 1 / Timer Channel 1 |
| Pin 3 | PTF2/TCH2 — Port F bit 2 / Timer Channel 2 |
| Pin 4 | PTF3/TCH3 — Port F bit 3 / Timer Channel 3 |
| Pin 5 | PTF4/TCH4 — Port F bit 4 / Timer Channel 4 |
| Pin 6 | PTF5/TCH5 — Port F bit 5 / Timer Channel 5 |
| Pin 7 | VDD — Positive power supply (5V) |
| Pin 8 | VSS — Ground |
| Pin 9 | OSC1 — Crystal oscillator input |
| Pin 10 | OSC2 — Crystal oscillator output |
| Pin 11 | RST — Reset input (active low) |
| Pin 12 | IRQ — External interrupt request |
| Pin 13 | BKGD — Background debug / mode select |
| Pin 14 | PWM6 — PWM channel 6 output |
| Pin 15 | PWM5 — PWM channel 5 output |
| Pin 16 | PWM4 — PWM channel 4 output |
| Pin 17 | PWM3 — PWM channel 3 output |
| Pin 18 | PWM2 — PWM channel 2 output |
| Pin 19 | PWM1 — PWM channel 1 output |
| Pin 20 | VSS — Ground |
| Pin 21 | PTE0/TxD — Port E bit 0 / SCI transmit |
| Pin 22 | PTE1/RxD — Port E bit 1 / SCI receive |
| Pin 23 | PTE2 — Port E bit 2 |
| Pin 24 | PTE3 — Port E bit 3 |
| Pin 25 | PTE4 — Port E bit 4 |
| Pin 26 | PTE5 — Port E bit 5 |
| Pin 27 | PTA0 — Port A bit 0 |
| Pin 28 | PTA1 — Port A bit 1 |
| Pin 29 | PTA2 — Port A bit 2 |
| Pin 30 | PTA3 — Port A bit 3 |
| Pin 31 | PTA4 — Port A bit 4 |
| Pin 32 | PTA5 — Port A bit 5 |
| Pin 33 | PTA6 — Port A bit 6 |
| Pin 34 | PTA7 — Port A bit 7 |
| Pin 35 | PTB0/ATD0 — Port B bit 0 / ADC channel 0 |
| Pin 36 | PTB1/ATD1 — Port B bit 1 / ADC channel 1 |
| Pin 37 | PTB2/ATD2 — Port B bit 2 / ADC channel 2 |
| Pin 38 | PTB3/ATD3 — Port B bit 3 / ADC channel 3 |
| Pin 39 | PTB4/ATD4 — Port B bit 4 / ADC channel 4 |
| Pin 40 | PTB5/ATD5 — Port B bit 5 / ADC channel 5 |
| Pin 41 | PTB6/ATD6 — Port B bit 6 / ADC channel 6 |
| Pin 42 | PTB7/ATD7 — Port B bit 7 / ADC channel 7 |
| Pin 43 | PTC0/ATD8 — Port C bit 0 / ADC channel 8 |
| Pin 44 | PTC1/ATD9 — Port C bit 1 / ADC channel 9 |
| Pin 45 | PTC2/ATD10 — Port C bit 2 / ADC channel 10 |
| Pin 46 | PTC3/ATD11 — Port C bit 3 / ADC channel 11 |
| Pin 47 | PTC4 — Port C bit 4 |
| Pin 48 | PTC5 — Port C bit 5 |
| Pin 49 | PTC6 — Port C bit 6 |
| Pin 50 | PTC7 — Port C bit 7 |
| Pin 51 | PTD0/FAULT — Port D bit 0 / PWM fault input |
| Pin 52 | PTD1 — Port D bit 1 |
| Pin 53 | PTD2 — Port D bit 2 |
| Pin 54 | PTD3 — Port D bit 3 |
| Pin 55 | PTD4 — Port D bit 4 |
| Pin 56 | PTD5 — Port D bit 5 |
Typical Applications
MC908MR32CBE is suitable for 6 applications: Washing Machine Motor Drive, Three-Phase Ceiling Fan Inverter, Switched-Mode Power Supply Primary Controller, Appliance Control Board (White Goods), BLDC Hobby Motor / Drone Controller, Industrial 5V Fan Pump Controller.
Washing Machine Motor Drive
The MC908MR32CBE's 6-channel 12-bit PWM with dead-time insertion and 10-bit ADC make it a strong fit for washing-machine drum and pump motors where 8-bit determinism and on-chip fault inputs reduce BOM cost. The 8 MHz HC08 core delivers predictable loop timing for direct mains-fed inverter control, while 32KB Flash holds speed-ramp tables and diagnostic code. Designers leverage the integrated current-sense ADC for closed-loop torque control without external DSP hardware. The 56-PSDIP through-hole package also streamlines quick-turn industrial design and field repair.
Recommended
Three-Phase Ceiling Fan Inverter
For ceiling-fan and HVAC-fan inverters, the MC908MR32CBE drives six PWM outputs in complementary mode with programmable dead time, eliminating external gate-driver logic. Its 4.5V-5.5V operating range tolerates rectified mains-rail supply variation, while the 10-bit ADC senses motor current and BEMF for sensorless commutation firmware. The HC08 instruction set keeps interrupt latency predictable at the 8 MHz bus clock, critical when commutating at 24 kHz PWM. 32KB Flash fits full sine-table, ramp, and fault-handler routines on a single chip.
Recommended
Switched-Mode Power Supply Primary Controller
In primary-side SMPS controllers the MC908MR32CBE substitutes a low-cost digital controller for legacy UC3842-style analog ICs. Its high-resolution PWM and 10-bit ADC let the HC08 implement peak-current-mode control with adjustable slope compensation, while 32KB Flash stores the entire digital-compensation firmware plus telemetry. The 5V supply rails ride directly off auxiliary winding bias with no extra LDO required. Programmable dead time protects synchronous-rectifier FETs during soft-start.
Recommended
Appliance Control Board (White Goods)
White-goods main boards rely on the MC908MR32CBE for cost-effective deterministic control of relays, valves, and BLDC pumps. The 8-bit HC08 core runs long-term appliance firmware comfortably within 32KB Flash budget, while the 10-bit ADC reads temperature sensors (NTCs) and pressure transducers for closed-loop appliance cycles. The wide 4.5V-5.5V supply range tolerates mains-derived 5V ripple, and FLASHplus allows factory-line firmware upgrades without a programming socket. The 56-PSDIP package simplifies hand-rework in service centers.
Recommended
BLDC Hobby Motor / Drone Controller
Hobby-grade BLDC controllers and small drone ESCs use the MC908MR32CBE because it integrates 6-channel 12-bit PWM with dead-time and 10-bit current-sense ADC on a 5V rail. The HC08 core handles trapezoidal or simple sine commutation at 8 MHz with predictable interrupt latency, while the Flash-plus in-circuit programming interface lets hobbyists reflash without a socketed chip. 56-PSDIP through-hole package is friendly to breadboard prototyping in DIY open-source ESC designs.
Recommended
Industrial 5V Fan Pump Controller
Industrial HVAC and small water-pump controllers pair the MC908MR32CBE with a 5V power supply on a PSDIP-friendly PCB. The MCU's 768B RAM is more than enough for sensor-data ping-pong buffers and PID state, while 12 PWM channels drive multiple pumps or fans simultaneously. The wide -40C to +85C operating temperature handles industrial-cabinet installations, and the 10-bit ADC provides local temperature and pressure feedback. Drop-in upgrade path to MC908MR32CFU (QFP) exists for SMD migrations.
Recommended
Recommended Products Summary
Engineering reference data for MC908MR32CBE — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC908MR16CBE | MC908MR32VFU | MC908MR32CFU |
|---|---|---|---|---|
| Package | 56-PSDIP | 56-PSDIP - same | 56-QFP - different package | 56-QFP - different package |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Core | HC08 (8-bit) | HC08 (8-bit) | HC08 (8-bit) | HC08 (8-bit) |
| Flash Memory | 32 KB | 16 KB (-50%) | 32 KB (same) | 32 KB (same) |
| RAM Size | 768 B | 768 B (same) | 768 B (same) | 768 B (same) |
| Maximum Clock Frequency | 8 MHz | 8 MHz (same) | 8 MHz (same) | 8 MHz (same) |
| Supply Voltage Range | 4.5V to 5.5V | 4.5V to 5.5V | 4.5V to 5.5V | 4.5V to 5.5V |
| PWM Channels | 6 x 12-bit | 6 x 12-bit (same) | 6 x 12-bit (same) | 6 x 12-bit (same) |
| ADC Resolution / Channels | 10-bit / 12 channels | 10-bit / 12 channels | 10-bit / 12 channels | 10-bit / 12 channels |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
| Mounting Style | Through Hole | Through Hole | Surface Mount | Surface Mount |
Key Differentiators
- 56-PSDIP through-hole package serviceable for industrial repair (vs MC908MR32VFU (56-QFP))
- Upward-compatible 32KB Flash (vs MC908MR16CBE (16KB))
- Motor-control-optimized PWM with dead-time insertion (vs MC908AP32CFBE (general-purpose AP))
Design Notes
Place a 100 nF ceramic decoupling capacitor as close as possible to each VDD/VSS pin pair (per the NXP HC08MR datasheet Figure on bypass). Add a single 10 uF to 100 uF bulk electrolytic near the MCU to sink PWM-driver switching transients. The 5V rail must hold above 4.5V across full load to avoid low-voltage-reset, particularly during motor inrush events.
Route the six PWM outputs in matched-length pairs so complementary-channel dead-time accuracy is preserved. Keep the PWM traces away from ADC analog inputs to minimize digital-to-analog crosstalk. The BKGD/IRQ pins should be pulled to header pads so in-circuit programming remains accessible after board assembly. Crystal traces to OSC1/OSC2 should be short and surrounded by a grounded guard ring.
Estimated: At 32KB Flash and 8 MHz bus, an external 4 MHz crystal with on-chip PLL is the typical clocking configuration; do not exceed the 8 MHz maximum bus frequency. Watch for the difference between Flash erase-block sizes when designing in-application firmware updaters - the HC08MR Flash is divided into fixed sectors. Avoid applying power to the MCU before the 5V rail fully stabilizes, as partial-voltage programming can corrupt Flash rows.
Compliance Information
Specific RoHS/REACH statements are not present in the verified distributor data for MC908MR32CBE. NXP/Freescale HC08 legacy MCU pages frequently omit the RoHS badge for older part revisions; designers should verify with the manufacturer declaration or by requesting a CoC before design-in.
