This report presents the design of a digital oscilloscope for a Digilent D2SB system board connected to a DIO4 and AIO1 peripheral boards. The AIO1 peripheral board is used for analog signal acquisition and analog to digital conversion; the values obtained from the A/D conversion are routed onto the D2SB system board and stored in a memory module implemented in the FPGA; a video controller, also implemented on the D2SB, fetches these values and generates the appropriate video signals which are sent to the DIO4 peripheral board and used to display an image on a monitor connected to the board. A basic interaction with the user is possible through the buttons and switches of the DIO4 board. The design implements common features of a conventional oscilloscope, such as sampling rate adjustment, hold and triggering. The design is complete, meets all requirements, and it has been verified through simulation and physical implementation.
The design is designed partly in VHDL, partly in schematic drawings and targets a Xilinx Spartan-2E FPGA. However, since the design was tailored specifically for the aforementioned boards it is highly unlikely that it can be ported to other hardware. The circuits were designed on a Windows XP using the Xilinx WebPack 6.2 tool. The transfer of the design to the FPGA was carried out either with the Xilinx Impact tool through a parallel JTAG cable or with the Digilent Export utility through a USB JTAG cable.
The analog signal was obtained from a PC soundcard, being created by third party software, Sonic SoundForge v4.5, also running on Windows XP.