Universidad Tecnológica Nacional (Regional Buenos Aires)
Department of Electronics
Cathedra: Digitals Techniques III
Professor: Eng. Alejandro Furfaro

    During the year 2001 I took a course on Digital Techniques III from the 5º year of the Electronics Engineering career of the Technological National University (UTN) in Buenos Aires. I carried out an USB bus project that I expounded here.
With this project the cathedra is looking for acquire the knowledge of the new technology, replacement of the old ISA , and as an option from impossible PCI.
Although there is not many information about USB, it's possible to develop an USB interface , with relative easiness.
I found very useful the programs that comes with Motorola's & National's evaluation board. These firms are providing USB controllers.Motorola have a HC08 with embedded USB controller.
For this project I used a HC11E2 microcontroller, with an external NATIONAL USBN9603 controller. This is full speed device(12 Mb/s).
There are many commercial drivers, like Thesycon driver which I used here. With this driver the firmware is easier than if a HID (Human Interface Device) driver is used , that are included with Windows. That option increase the difficulty of firmware programming.
The firmware is entirely programmed in HC11's assembler. The system is autonomous, and it sends the weight data & exit opened to the PC. The PC sends the weight limit assignation table for each exit.
The PC's soft is programmed in Visual C++.

Project's Description: USBBalance.doc

    This project board carry out the weighting duty of a fruit classification line and it is autonomous.
The balance is formed by a load cell followed by its amplifier and filter. The HC11 microcontroller have an internal 8 bits A/D converter, perhaps this is a low resolution for this job, but the important was the USB interface.
SPI bus is used to communicate HC11 with USBN9603 (this also allows the using of a parallel interface)

(See detailed description in file USBBalance.doc)

HC11E2's firmware (assembler): FirmUSB.zip

    Totally programmed in HC11's assembler. All USB norm's standard function are carried out.
(See detailed description in file USBBalance.doc)

PC software (Visual C++ 6.0): SoftPC.zip

    It uses the C functions provided by Thesycon driver's library to USB communication. It permits balance's calibration
and weighting statistics are carried out.
(See detailed description in file USBBalance.doc)

Printed boards and schematics (Orcad 9): Circuitos.zip

                                 Components side                                                                     Soldering side