W78ERD2A40PL - 40MHz 8-Bit 64KB Flash MCU | Nuvoton
MPN： W78ERD2A40PL ✓ 啟用中W78ERD2A40PL 概覽
A microcontroller is a programmable semiconductor that integrates a CPU, program memory, data memory, I/O ports, timers, interrupts, and serial-interface functions on one integrated circuit. The W78ERD2A40PL belongs to the 8-bit MCU hierarchy and follows the 8052 architecture. Within an embedded system, its flash memory stores the application program, while its ports and peripheral blocks connect the processor to sensors, indicators, actuators, and external communication circuits.
The device combines 64 KB of flash with 256 bytes of on-chip RAM, 1 KB of auxiliary RAM, and 36 bidirectional I/O lines. Four 8-bit, bit-addressable ports are supplemented by a four-bit P4 port. Its three 16-bit timer/counters support periodic timing, event counting, and waveform generation, while the serial port provides a dedicated serial communications channel. The four-level interrupt priority system helps the firmware manage timing-sensitive events across nine interrupt sources.
The W78ERD2A40PL operates at up to 40 MHz and is identified as an 8052-class W78 device. Its six-transistor flash implementation supports 64 KB of program storage and a separate 4 KB boot block for firmware management requirements. Idle and power-down modes provide two ways to reduce activity when the application does not need continuous processing, making the MCU suitable for both continuously active equipment and duty-cycled embedded products.
Typical uses include industrial controllers, sensor-interface equipment, keypad and display modules, motor or relay control, programmable logic controllers, and communication-oriented embedded systems. Its 36 available I/O pins provide useful parallelism for discrete inputs and outputs, while the timer blocks reduce the need for external timing components. In a communications product, the serial port and interrupt architecture can support a host link or supervisory protocol alongside local real-time control.
Designers should verify oscillator, reset, memory, and peripheral connections against the manufacturer datasheet before layout release. A 5 V supply is required for the stated operating configuration, so power sequencing, input levels, and decoupling must match the device requirements. PLCC assembly also requires attention to footprint pad geometry and soldering-profile control. The four-level interrupt priority and two low-power modes should be considered early when defining firmware architecture.
This page consolidates the device identity, electrical specifications, memory architecture, peripheral resources, application guidance, and sourcing considerations into one engineering reference. It also distinguishes documented capabilities from unknown package-pin assignments and avoids presenting unverified substitute parts as drop-in replacements.
直接替換替代品，適用於 W78ERD2A40PL — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此產品無可直接替換的替代品。
申請替代品W78ERD2A40PL 最大額定值與電氣特性
| Product Type | 8-bit microcontroller (MCU) |
| Architecture | 8052 W78 |
| 最大時脈頻率 | 40 MHz |
| Program Memory Size | 64 KB (64K x 8) |
| Boot Block Size | 4 KB |
| Flash Technology | 6T |
| On-Chip RAM | 256 bytes |
| Auxiliary RAM | 1 KB |
| Number of I/O Pins | 36 |
| General-Purpose Ports | 4 x 8-bit, bi-directional, bit-addressable |
| Additional Port | 4-bit P4 |
| Timer/Counter Count | 3 x 16-bit |
| Serial Port | 1 |
| Interrupt Sources | 9 |
| Interrupt Priority Levels | 4 |
| Power-Reduction Modes | 2: idle and power-down |
| Operating Supply | 5 V |
| Programmable Comparator Array | PCA |
| 封裝 | 44-pin PLCC |
| Lead-Free Status | Pb-free |
W78ERD2A40PL 44-pin plcc 腳位配置指南
W78ERD2A40PL（44-pin plcc 封裝）的腳位配置。 此數位 IC 包含 GPIO、通訊介面（UART、SPI、I2C）與電源腳位。替代腳位功能與配置選項請參閱製造商資料表。對嵌入式系統設計與 PCB 佈局至關重要。
無詳細腳位定義資料： W78ERD2A40PL.
請參閱 資料表 以查看完整腳位配置。
典型應用
W78ERD2A40PL 適用於 6 應用s: Industrial Sequence Controller, Serial Data Acquisition Module, Programmable Logic Controller, Keypad and Display Control, Motor and Relay Control, Sensor Interface Node.
Industrial Sequence Controller
The W78ERD2A40PL fits a compact industrial sequence controller because its 36 I/O pins support multiple discrete inputs, status indicators, and actuator commands without requiring extensive external interface logic. Three 16-bit timer/counters can handle timed production steps, pulse measurement, or repetitive output events at the 40 MHz operating frequency. The four-level interrupt system allows timing-sensitive tasks to take priority over background operations. In a controller enclosure, the MCU can operate from a regulated 5 V rail, poll sensors, update the human interface, and maintain a deterministic control sequence. The 64 KB flash area provides room for application code, while the separate 4 KB boot block supports controlled startup or firmware-management routines.
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Serial Data Acquisition Module
The W78ERD2A40PL is suitable for a serial data-acquisition module that combines a communications link with local digital control. Its serial port provides a dedicated path for receiving commands or measurement data, while nine interrupt sources and four priority levels help separate communication handling from time-critical control functions. The 36 available I/O pins can connect sensor-enable signals, status indicators, alarm outputs, and a front-panel interface. With 64 KB of flash for protocol and application code, the MCU can support more complex firmware than a minimal controller while remaining an 8-bit embedded design. Idle and power-down modes offer additional control over activity when the acquisition module operates intermittently.
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Programmable Logic Controller
The W78ERD2A40PL can serve as the core of a compact programmable logic controller because it combines 8052-compatible processing, 36 I/O pins, three timer/counters, and priority-controlled interrupts. Inputs can be sampled through the four bidirectional eight-bit ports and the auxiliary four-bit P4 port, while outputs can drive relays, lamps, or interface logic subject to the device's electrical limits. The 40 MHz clock provides ample timing margin for scan-based control tasks, and 64 KB of flash supports configuration tables and application logic. The 4 KB boot block is also useful when the product design separates boot code from the main application. Firmware should define safe output states, communication timeouts, and power-up behavior before connecting the controller to external equipment.
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Keypad and Display Control
The W78ERD2A40PL fits keypad and display-control products where many digital lines are needed for human-interface hardware. Four eight-bit bidirectional ports provide a practical base for matrix-keypad scanning, display strobes, indicator control, and communication signals, while the additional P4 port expands the available digital interface. Three 16-bit timer/counters can support display refresh timing, debounce intervals, or periodic system tasks. At up to 40 MHz, the 8052-class core can manage both interface updates and application logic, and the 64 KB flash area accommodates display tables, character maps, and menu firmware. The 44-pin PLCC package provides adequate pin count for a permanent-board or leaded assembly rather than forcing multiple external interface devices.
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Motor and Relay Control
The W78ERD2A40PL is appropriate for small motor-control and relay-control subsystems that need multiple discrete signals, event timing, and coordinated shutdown behavior. The 36 I/O lines can represent direction commands, enable signals, speed or position inputs, switch feedback, and fault outputs. Three 16-bit timer/counters can generate periodic control sequences or measure input events, while the interrupt priority structure lets urgent fault handling override routine communication. Its 64 KB flash capacity supports motion tables, operating profiles, and diagnostic logic, and the separate 4 KB boot block can hold startup validation. Designers must add suitable driver, isolation, flyback, and protection circuitry because the MCU's I/O pins are control signals rather than direct high-power motor outputs.
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Sensor Interface Node
The W78ERD2A40PL works as a local sensor-interface node for systems that combine digital sensors, status reporting, and real-time event handling. Its four eight-bit bidirectional ports plus P4 offer enough parallel connectivity for sensor-enable lines, threshold signals, alarm outputs, and diagnostic inputs. The nine interrupt sources and four priority levels support responsive handling of events across multiple peripheral blocks, while the serial port can carry summarized measurements to a host controller. With 256 bytes of on-chip RAM and 1 KB of auxiliary RAM, the design benefits from the dedicated auxiliary area for buffering or state management. Idle and power-down modes can reduce consumption in periodically sampled installations, provided the firmware defines which peripherals must remain active during each mode.
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工程參考資料，適用於 W78ERD2A40PL — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 |
|---|---|
| Architecture | 8052 W78 8-bit MCU |
| Maximum Clock Frequency | 40 MHz |
| Program Memory | 64 KB (64K x 8) |
| Boot Block | 4 KB |
| On-Chip RAM | 256 bytes |
| Auxiliary RAM | 1 KB |
| Number of I/O Pins | 36 |
| Timer/Counters | 3 x 16-bit |
| Interrupt Sources | 9 sources with 4 priority levels |
| Power-Reduction Modes | Idle and power-down |
| Supply Voltage | 5 V |
| Package | 44-pin PLCC |
| Brand | Nuvoton Technology Corporation |
主要差異化特點
- Substantial program and boot memory for an 8-bit embedded controller (對比Generic 8052-class alternatives without a verified equivalent MPN)
- High parallel I/O availability (對比Smaller 8-bit MCUs with fewer external interface lines)
- Integrated timing and prioritized event handling (對比Basic 8052 designs requiring more external timing resources)
設計說明
Design the W78ERD2A40PL around its documented 5 V operating supply and follow the manufacturer datasheet for voltage limits, reset behavior, and decoupling requirements. Place the required supply capacitors close to the device's power and ground connections, and keep switching or high-current return paths away from sensitive input traces. Confirm external driver levels before attaching them to the bidirectional ports because the MCU operates from a 5 V supply.
Use the manufacturer package drawing to establish the 44-pin PLCC footprint, pad dimensions, solder-mask geometry, and assembly orientation. Keep the pin-1 marking unambiguous and provide adequate clearance around the package perimeter. Because this page does not reproduce the authoritative pin assignments, do not release the layout from a generic PLCC symbol; cross-check every net against the manufacturer pin-description table.
Do not treat a generic 8052 as a drop-in substitute merely because the instruction set and clock rating appear similar. Verify the complete 44-pin pinout, memory organization, boot-block behavior, timer resources, serial-port implementation, interrupt vectors, oscillator arrangement, reset logic, and electrical limits. A software port can also require initialization changes even when the external footprint is retained, so evaluate both hardware and firmware compatibility.
Plan interrupt priorities and low-power transitions before completing the application firmware. The device has nine interrupt sources and four priority levels, allowing urgent faults to override routine serial or timer servicing. Idle and power-down modes should preserve only the peripherals required for wake-up and data retention, and outputs should be placed in defined safe states during reset and shutdown to avoid unintended actuator activation.
合規資訊
The manufacturer listing identifies the W78ERD2A40PL as Pb-free. RoHS, REACH, halogen-free, and conflict-minerals status are not stated in the available product information. AEC-Q100 is not applicable because this product is a general-purpose 8-bit microcontroller rather than an automotive-qualified device.