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The USBmicro U421 USB Interface
The U421 is a USB solution that is pre-built, pre-programmed, and pre-tested and will get you interfacing your PC (Win⁄Linux) or Mac (OSX) to various devices in very little time! There is no USB device assembly, no driver development, and no firmware to write. In many cases the U421 can be plugged into an experimenter's breadboard and circuit interfacing can begin immediately. Demo software applications can be used "right out of the box".
U421 top view.
Features of the U421 USB Interface
Overview of the U421 USB Interface
The U421 provides a simple digital i⁄o interface for the PC (Win⁄Linux) or Mac (OSX) . Sixteen i⁄o lines from the microcontroller are provided. Commands can be sent to the U421 that change the i⁄o lines from input to output. I⁄o lines can be individually selected as inputs or outputs. The U421 supports commands to read the ports, and if the ports are set to output, to write to the ports.
The U421 is an interface to SPI (Serial Peripheral Interface) devices. SPI is a local synchronous serial bus that uses a clock line, two data lines, and a device select line for communication between a serial device and a host microcontroller. The firmware on the U421 provides generic access to read and write SPI devices. The SPI clock rate can be adjusted to 62.5 kHz, 500 kHz, 1 MHz, or 2 MHz. Because additional pins are available as generic i⁄o, the U421 can use these lines as slave select lines and address multiple SPI devices.
The SPI subsystem of the U421 can be used as a master to communicate with SPI devices such as EEPROMS and A⁄D converters. The U421 can also be used as a SPI slave to a microcontroller that uses the U421 as a gateway to the PC (Win⁄Linux) or Mac (OSX) . A PIC, for example, can act as a SPI master to communicate data with the U421, which can then transfer the data to a PC (Win⁄Linux) or Mac (OSX) application. Most microcontrollers can communicate via SPI with software-driven routines, many have internal SPI hardware. SPI hardware is present on microcontrollers from little 8-bit devices, like the PIC, to 32-bit microcontrollers like the 680x0-based devices.
The U421 is a convenient way to interface a standard Hitachi-type of intelligent LCD controller to USB. The commands that support communication to the LCD module are the "standard" LCD commands. Standard commands include writing characters to the display, and controlling the display.
The U421 is an assembled and tested circuit card that is 1.5 inches (38.1mm) long and 0.75 inches (19.1mm) wide. The U421 is a printed circuit board in a 24-pin "DIP-like" format.
The U421 interfaces to the PC (Win⁄Linux) or Mac (OSX) via the USB port. An application on the PC (Win⁄Linux) or Mac (OSX) controls the U421. The U421 does not use any custom drivers, just the drivers that are a part of the operating system. Custom software can be developed to use the U421, or the applications that have been created as examples here can also be used.
Uses for the U421 USB Interface
With the U421 you can utilize the USB port on your computer to interface to various electronic devices, such as: lights, LCD displays, SPI analog and memory devices, switches, relays, tethered robots, model railroad control, and many custom circuits.
See the ODN U4x1 Application Notes section for examples of using the U421.
Product suitability for your particular purpose⁄use
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|Hardware: U401 USB Interface U421 USB Interface U451 USB Interface|
Programming: USBm DLL Programming Download Files
Application Notes: U4x1 Application Notes Misc Applications and Information FAQ
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