Renesas M37221EASP

Overview

M37221EASP from Renesas Electronics is a single-chip 8-bit CMOS microcomputer with integrated on-screen display (OSD) controller, electrically programmable PROM (40 KB ROM), 704-byte RAM, six-channel 6-bit A-D comparator, and two 6-bit D-A converters - designed specifically for TV voltage synthesizer and channel selection systems requiring real-time video overlay and analog signal generation.

For engineers reviewing the M37221EASP datasheet, M37221EASP pinout, M37221EASP application, or M37221EASP equivalent, this device delivers verified OSD timing control (HSYNC/VSYNC), RGB output capability (P52–P55), dual D-A outputs (P30/DA1, P31/DA2), and 128-level subroutine nesting - critical for embedded TV firmware with layered graphics and analog tuning interfaces.

Technical Context

The M37221EASP implements a 740-family CPU core with 71 basic instructions and 0.5 µs minimum instruction execution time at 8 MHz. Its dual-clock architecture includes separate main oscillator (XIN/XOUT) and OSD clock (OSC1/OSC2) circuits, enabling independent timing for video synchronization and system logic.

It integrates a dedicated OSD engine supporting 24×2 character display (12×16 dot matrix), 8-color per-character rendering (R/G/B), horizontal/vertical positioning (64×128 levels), and border attributes - all driven by dedicated hardware registers and synchronized to external HSYNC/VSYNC inputs.

Key Specifications

Pinout & Package

Package: 42-pin plastic molded SDIP (Outline 42P4B), lead pitch 1.778 mm, body width 15.24 mm.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microcontroller-with-OSD applications.

Compared with M37221MAH-XXXSP and uPD78F0503GC-GBA-AX, the M37221EASP uniquely combines electrically programmable PROM, hardware OSD timing, and dual D-A outputs in a single 42-pin SDIP package - making it irreplaceable for cost-sensitive, high-volume TV voltage synthesizer designs requiring minimal BOM and deterministic video overlay.

Availability

M37221EASP is available at Aetrix Electronics and suitable for TV channel selection systems, voltage synthesizer modules, on-screen display generators, and legacy tuner interface designs requiring stable component supply across extended production lifecycles.

Supply support for M37221EASP 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 Electronics Corporation, formed in 2010 via merger of NEC Electronics and Renesas Technology, is a global semiconductor leader focused on microcontrollers, analog, and power solutions for automotive, industrial, and consumer markets.

The M37221EASP belongs to Renesas' legacy 740-family 8-bit microcontroller line, engineered specifically for cost-optimized TV subsystems requiring integrated OSD, analog tuning, and real-time video synchronization - targeting high-volume consumer electronics manufacturing.

FAQ

What is the primary function of the M37221EASP in TV systems?

The M37221EASP serves as a single-chip solution for TV voltage synthesizer control and on-screen display generation. It executes channel selection firmware, drives RGB overlay signals via P52–P55, accepts HSYNC/VSYNC for precise raster alignment, and outputs analog tuning voltages through its two integrated 6-bit D-A converters (DA1/DA2). This integration eliminates discrete DACs and video timing ICs in legacy TV designs.

Does the M37221EASP support in-system programming of its PROM?

No, the M37221EASP features one-time programmable (OTP) PROM. Programming occurs during manufacturing using dedicated PROM programmers; it cannot be reprogrammed in-circuit or after soldering. The "EASP" suffix denotes the OTP version with electrically written PROM, distinct from mask-ROM variants like M37221M8H-XXXSP. Field updates require hardware replacement.

How does the M37221EASP handle video synchronization signals?

The M37221EASP uses dedicated Schmitt-trigger input pins HSYNC and VSYNC (pins 30 and 31) to accept external horizontal and vertical sync pulses. These signals directly feed the OSD engine's position counters, enabling hardware-aligned character placement at 64 horizontal and 128 vertical levels - independent of CPU timing and ensuring flicker-free, stable overlay registration.

What are the key differences between M37221EASP and M37221MAH-XXXSP?

The M37221EASP and M37221MAH-XXXSP share identical ROM (40 KB), RAM (704 bytes), and 42-pin SDIP packaging, but only the M37221EASP includes two 6-bit D-A converters (DA1/DA2 on P30/P31) and dedicated OSD clock I/O (OSC1/P33, OSC2/P34). The MAH variant lacks these analog and timing peripherals, requiring external components for voltage synthesis and OSD clock generation.

Can the M37221EASP operate with a 3.3 V supply?

No, the M37221EASP is specified exclusively for 5 V ±10% operation (4.5 V to 5.5 V). Its I/O structures, internal regulators, and oscillator circuitry are designed for 5 V CMOS logic levels. Using 3.3 V will result in undefined behavior, failed startup, or permanent damage. For 3.3 V systems, a level-shifting interface or alternative microcontroller must be used.