Desenvolvimento de uma interface USB - I/O analógica e digital

Abstract

Computers today are getting more accessible to everyone and the personal computer is being use in almost all human activities. In some applications, like physics educational laboratories, often the computer is used to control experiments. In such cases, a hardware interface is made necessary. Here, we propose hardware with respective software solution. Aim those that are not expert in computing and low level software programming, we elected these requirement: i) an interface that could read analog and digital signals; ii) an interface that could write analog and digital signals; iii) an interface that communicates with the computer using USB port, because USB is found in almost all computer (desk top and portables); iv) an interface that communicates with a high level software, like Python. In such way that the final users do not need know microprocessor instructions to be able programming the interface. To easily the diffusion of the interface, we make free to everyone the layout of print circuit board of the interface. The interface is based in a microcontroller, PIC18F2550, made by Microchip. Was developed an hardware programmer for PIC18F family, based on PicKit2 from Microchip. The programmer will allow those people that want develop a deeper microcontroller programming of PIC18F to dump his software on the microcontroller and do testes. An application is presented: a temperature water control using the interface and Python language.