Renesas HD64F3687HV

Overview

HD64F3687HV from Renesas Electronics is a 16-bit single-chip microcomputer in the H8/300H Tiny Series, featuring an H8/300H CPU core with H8/300 instruction set compatibility, 64 KB on-chip ROM, 4 KB RAM, and integrated peripherals including UART, timer/counters, and I/O ports - used in industrial control panels and embedded instrumentation requiring deterministic real-time response.

For engineers reviewing the HD64F3687HV datasheet, HD64F3687HV pinout, HD64F3687HV application, or HD64F3687HV equivalent, key selection criteria include its 64-pin QFP package, 20 MHz max operating frequency, ROM-based program storage, low-power sleep/standby modes, and support for on-board programming via SCI channel 1 in boot mode.

Technical Context

The HD64F3687HV implements the H8/300H CPU architecture with 16-bit data bus and 24-bit address space, supporting both big-endian memory layout and multiple exception vectors including reset, NMI, and 32 interrupt sources. Its system clock generator accepts external crystal (1–20 MHz), ceramic resonator, or external clock input, while the subclock generator supports 32.768 kHz crystal for RTC functions.

Power management includes four low-power modes - Sleep, Standby, Subsleep, and Subactive - controlled by SYSCR1/SYSCR2 and MSTCR1/MSTCR2 registers. Peripheral modules are selectively disabled via module standby control to reduce current consumption, with wake-up capability from external interrupts or internal timers.

Key Specifications

Pinout & Package

HD64F3687HV is housed in a 64-pin plastic QFP (Quad Flat Package) with 0.8 mm lead pitch, JEDEC MS-026 compliant, suitable for reflow soldering and industrial thermal cycling.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit microcontroller applications.

Compared with HD64F3687F and HD64F3684, the HD64F3687HV offers full 64 KB ROM capacity and integrated subclock generation in the same 64-pin QFP footprint - making it optimal for feature-complete, time-aware embedded controllers where firmware growth headroom and autonomous timekeeping are required.

Availability

HD64F3687HV is available at Aetrix Electronics and suitable for industrial control panels, embedded data loggers, test equipment interfaces, and medical diagnostic instruments requiring stable component supply and long-term obsolescence management.

Supply support for HD64F3687HV 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 is a Japanese semiconductor manufacturer specializing in microcontrollers, analog, and power devices for industrial, automotive, and infrastructure markets.

The HD64F3687HV belongs to the H8/300H Tiny Series - designed for cost-sensitive, resource-constrained embedded systems requiring deterministic real-time performance, low power, and high integration without external memory.

FAQ

What is the maximum operating frequency of the HD64F3687HV?

The HD64F3687HV operates at a maximum frequency of 20 MHz when powered at VCC = 5 V. This frequency is derived from the system clock generator, which supports external crystal (1–20 MHz), ceramic resonator, or direct clock input. The CPU executes instructions at this rate, enabling real-time control loops with sub-50 µs interrupt latency. HD64F3687HV maintains timing integrity across its full temperature range (−20°C to +75°C) under specified supply conditions.

Does the HD64F3687HV support in-system programming?

Yes, the HD64F3687HV supports on-board programming via its SCI channel 1 (P21/RXD, P22/TXD) when configured in boot mode. This allows firmware updates without removing the device from the PCB or using external programmers. The process requires asserting the appropriate boot mode pins at reset and sending a defined command sequence over UART. HD64F3687HV's on-chip ROM is mask-programmed, so boot-mode programming applies only to development and initial provisioning - not field rewrites.

What power-saving modes does the HD64F3687HV offer?

The HD64F3687HV provides four low-power modes: Sleep, Standby, Subsleep, and Subactive - controlled by SYSCR1, SYSCR2, MSTCR1, and MSTCR2 registers. In Standby mode, current drops below 10 µA while retaining RAM contents and allowing wake-up via external interrupt or timer. Subsleep uses the 32.768 kHz subclock for ultra-low-power periodic wake-up. HD64F3687HV's module standby function lets designers disable unused peripherals individually to further minimize leakage.

Is the HD64F3687HV pin-compatible with other H8/3687 series variants?

No, the HD64F3687HV is not universally pin-compatible across all H8/3687 series variants. While it shares the 64-pin QFP package with HD64F3687 and HD64F3687G, differences exist in NC pin assignments and emulator-reserved pins (e.g., P85–P87). HD64F3687F uses a 48-pin LQFP package and is physically incompatible. HD64F3687HV's pin functions align with the H8/3687N variant per the Hardware Manual Rev.5.00, confirming identical pinout within that subgroup.

What is the role of the subclock generator in the HD64F3687HV?

The subclock generator in the HD64F3687HV supports a 32.768 kHz crystal resonator for low-power timekeeping functions, such as real-time clock (RTC) operation during Sleep or Standby modes. It operates independently of the main system clock, enabling time-synchronized wake-up events without powering the full CPU. This circuit is absent in HD64F3684 and is a distinguishing feature of HD64F3687HV and HD64F3687N. HD64F3687HV uses this subclock to maintain accurate time stamps in battery-backed applications like data loggers.