Systèmes industriels - Systemtechnik

USB-SPI translator

Salamin, Yannick ; Bianchi, Christophe (Dir.)

Mémoire de bachelor : HES-SO Valais, 2010.

Objectives: The project involves the design of a communication interface between a computer and 37 serial interfaced D/A Converters to update their outputs and also process feedback information from the DACs outputs. Methods / Experiences / Results: A USB controller (FT245R) is used for the USB communication between the computer and the processing unit (ATmega88). The user is able to send the... Plus

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    Summary
    Objectives: The project involves the design of a communication interface between a computer and 37 serial interfaced D/A Converters to update their outputs and also process feedback information from the DACs outputs. Methods / Experiences / Results: A USB controller (FT245R) is used for the USB communication between the computer and the processing unit (ATmega88). The user is able to send the DACs update information toward the microcontroller which sends the digital values to the DACs. A CPLD device is used to select multiple channels of 37 DACs. The MCU can sample the DACs output voltage via its built-in A/D converter and then send the information to the computer in order to be displayed for the user. Two hardware boards are designed and fabricated. The main board, USB-SPI Translator which provides the power and data processing functions, is a general USB to SPI communication interface board. The other board is in charge of the DACs channels selection. After the realization of the hardware boards, firmware for the data processing unit (MCU) and the CPLD are written. Some experiments about the whole system demonstrate that the DACs are able to be updated individually with a desired voltage. The precision of the DACs outputs is about one decimal. The MCU can get a 10-bits digital value of the DACs output. The digitalized DACs outputs are transmitted to the computer and displayed for the user.