Renesas M37531E8FP

Overview

M37531E8FP from Renesas Technology Corp. is an 8-bit CMOS microcontroller based on the 740-family core, featuring 16 KB ROM, 384 bytes RAM, 10-bit 8-channel ADC, three 8-bit timers, UART and clock-synchronized serial I/O, and programmable I/O ports - designed for embedded control in home appliances and office automation equipment.

For engineers reviewing the M37531E8FP datasheet, M37531E8FP pinout, M37531E8FP application, or M37531E8FP equivalent, this device supports ceramic/RC/resonator clock sources, operates from 2.2–5.5 V across –20 to 85 °C, integrates a watchdog timer and key-on wake-up interrupt, and delivers 0.50 µs minimum instruction execution time at 8 MHz in high-speed mode.

Technical Context

The M37531E8FP implements a single-chip 8-bit CPU with zero-page and special-page memory addressing modes, supporting mask ROM configuration and operating in single-chip mode. Its interrupt system handles 12 sources (8 vectors), including external INT0/INT1, timer underflows, serial I/O events, and A-D conversion completion.

It integrates a built-in clock generating circuit compatible with ceramic resonators, quartz crystals, or RC networks; a 16-bit watchdog timer; and dual serial interfaces - UART (SI/O1) and clock-synchronized (SI/O2) - with configurable input levels (CMOS/TTL) on selected pins via P1P3C register.

Key Specifications

Pinout & Package

Package: 36P2R-A - 36-pin plastic molded SSOP, 0.8 mm pitch, surface-mount compatible.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit microcontroller applications.

Compared with R5F100LEA and HD64F7055, the M37531E8FP offers cost-optimized, production-ready mask ROM execution with integrated LED drive and key-on wake-up - ideal for high-volume, function-stable appliance control where flash flexibility is unnecessary.

Availability

M37531E8FP is available at Aetrix Electronics and suitable for home appliance control, office automation equipment, and factory automation sensors requiring stable component supply over long production lifecycles.

Supply support for M37531E8FP includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Renesas Technology Corp. is a Japanese semiconductor manufacturer formed in 2003 through the merger of Hitachi and Mitsubishi Electric's semiconductor operations, specializing in microcontrollers, analog, and power devices.

The 7531 Group - including M37531E8FP - was designed for cost-sensitive, high-reliability embedded control in consumer and industrial appliances, emphasizing integrated peripherals, low-power wake-up, and robust clocking options.

FAQ

What is the maximum operating frequency supported by the M37531E8FP?

The M37531E8FP supports a maximum XIN oscillation frequency of 8 MHz in high-speed mode, yielding a 0.50 µs minimum instruction execution time. It also supports lower-frequency ceramic and RC oscillation modes (down to 1 MHz), with corresponding voltage range adjustments per the datasheet specifications. The M37531E8FP does not support external clock frequencies above 8 MHz in standard operation.

Does the M37531E8FP include flash memory or is it mask ROM only?

The M37531E8FP uses mask ROM - specifically 16 KB of factory-programmed read-only memory - and does not include flash or EEPROM. This makes it suitable for high-volume, fixed-function applications where firmware revision is not required post-production. Other members of the 7531 Group (e.g., M37531E4FP) offer 8 KB mask ROM, but all variants in the E8 suffix denote 16 KB mask ROM configuration.

How many analog input channels does the M37531E8FP ADC support, and what is its resolution?

The M37531E8FP integrates a 10-bit successive-approximation A-D converter with 8 analog input channels (P20/AN0 through P27/AN7). All 8 channels are available in the 36P2R-A package variant. The ADC uses VREF as its reference voltage and supports single-ended sampling with internal sample-and-hold functionality. The M37531E8FP does not support differential input mode or hardware averaging.

Can the M37531E8FP drive LEDs directly, and which pins support this function?

Yes, the M37531E8FP can drive LEDs directly using P30 through P35 - six dedicated high-current sink output pins labeled LED0–LED5 in the pinout. These pins support higher sink current than standard GPIO, enabling direct connection to common-anode LED segments without external transistors. P36/INT1 and P37/INT0 do not support LED drive functionality. The M37531E8FP's LED drive capability is confirmed in the "I/O port P3" functional description and pin configuration diagrams.

What clock sources are supported by the M37531E8FP, and how are they configured?

The M37531E8FP supports ceramic resonators, quartz crystals, RC networks, and external clocks via the XIN/XOUT pins. Configuration is controlled by the CPU Mode Register (CPUM) bit 5: '0' selects ceramic oscillation, '1' selects RC oscillation. For RC mode, XIN and XOUT are shorted and connected to an external resistor-capacitor network. The M37531E8FP's clock generating circuit requires no additional components for ceramic or crystal use, and the CPUM register must be written once after reset to select the mode.