HOW AN AUTOMATED INSTRUMENTATION USING AN MS-DOS EMBEDDED CONTROLLER CAN BE SEEN AS A USB DEVICE BY ANY HOST PC

A way is described to transfer data in a fast and reliable way between an MS-DOS compatible controller, embedded in an automated instrumentation, and a host PC that runs Windows, Linux, or Mac OS, and that communicates through a standard USB port. This implementation allows the PC to see the controller as a USB device, and obviates both the lack of oheritageo ports on modern PC's and the unreliable timing of critical events on contemporary operating systems. The communication channel for data transfer is based on the FTDI FT245R chip. The 8-bit port of the chip is interfaced to the embedded controller with custom logic implemented on a programmable logic device, while the USB port is interfaced to the host PC using off-the-shelf libraries. Custom software implements the data transfers. The MS-DOS communication tasks are integrated in the controller program, with no degradation of control accuracy and speed.