MCP2221AT-I/STVAO: A Comprehensive Datasheet and Technical Overview
The MCP2221AT-I/STVAO from Microchip Technology is a highly versatile and widely adopted USB-to-UART/I²C serial converter bridge. This powerful integrated circuit (IC) serves as a critical communication intermediary, enabling seamless data transfer between a host computer's USB port and various peripheral interfaces common in embedded systems. Its combination of robust functionality, ease of use, and cost-effectiveness has made it a cornerstone component in countless development and production environments.
This article provides a detailed technical overview of the MCP2221A, exploring its key features, internal architecture, and typical applications.
Key Features and Capabilities
The MCP2221A distinguishes itself with a rich set of integrated features that minimize external component count and simplify design-in:
USB 2.0 Full-Speed Compatible (12 Mbps): Ensures fast and reliable data communication with the host PC.
Dual Protocol Support: It integrates a UART serial interface with full hardware flow control (CTS/RTS) and an I²C serial interface supporting both Master and Multi-Master modes with clock speeds up to 400 kHz.
Integrated Hardware Functions: The device includes multiple general-purpose I/O (GPIO) pins, some of which can be configured for specialized functions:
USB Voltage Regulator (3.3V): Powers the chip itself and can supply a limited amount of current to external logic.
On-Board Clock Source: Features an internal oscillator, eliminating the need for an external crystal.
4 User-Configurable GPIO Pins: Can be set as digital inputs or outputs.
3 Dedicated Pins for USB Status LEDs: (TX, RX, PWR) to provide visual communication feedback.
Serial Data Pins (SDA, SCL): For the I²C interface, which can also be configured as GPIO.
Internal Architecture and Pinout
The MCP2221AT-I/STVAO is offered in a compact 14-lead TSSOP package. Its internal architecture is built around a dedicated microcontroller that manages the USB protocol, translates commands, and controls the various peripheral interfaces.
The pinout includes:
USB Data Pins (D+ and D-): For connection to the host's USB bus.
UART Pins (TXD, RXD, RTS, CTS): For asynchronous serial communication.
I²C Pins (SDA, SCL): For the two-wire serial interface.
GPIO and Dedicated Pins: The remaining pins serve as configurable GPIOs or for specific functions like the status LEDs and power supply.
Typical Applications
The flexibility of the MCP2221A makes it suitable for a vast array of applications, including:
USB-to-Serial Adapters: Creating legacy COM ports for modern computers to interface with microcontrollers (e.g., Arduino, PIC, AVR), GPS modules, and other serial devices.
I²C Host Adapter/Programmer: Acting as a bridge for a PC to communicate with and program I²C-based EEPROMs, sensors, and other ICs.
Embedded Systems Programming and Debugging: Providing a simple USB interface for in-circuit programming and debugging of target microcontrollers.
General-Purpose USB Peripheral Control: Using its GPIO pins to control LEDs, read switches, or manage other simple digital functions directly from a PC.
Development and Support
Microchip provides extensive software support to accelerate development. The MCP2221A is supported by a free and easy-to-install USB driver, making it instantly recognizable by the operating system as a standard COM port. Additionally, the company offers utilities like the "MCP2221A DLL" for custom application development and the "MCP2221A Configuration Utility" to easily manage the device's settings, such as GPIO direction and USB vendor/product IDs.
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Keywords:
USB-to-UART Converter
I²C Master
Serial Bridge IC
Embedded Systems
GPIO Control
