LabVIEW 2015 SP1 FPGA Module Xilinx Tools Vivado 2014.4.Īn additional executable must be run. National Instruments Digital Systems Development Board.Multisim 14.0.1 or higher, Education Edition.You will need the following for this tutorial: This tutorial provides an example of how you can develop counters using the DSDB or any other Digilent FPGA board and use these to control the onboard 7-segment displays using Multisim and the PLD schematic.įor more details on installing and setting up the DSDB in Multisim, refer to the Getting Started with Digilent Boards in Multisim guide. Because of the inability of software-based simulations to meet the speed of hardware, gaining an understanding of timing can be difficult. Timing is a critical part of digital design.
The PLD schematic allows educators and students to create graphical logic diagrams like those found in textbooks and deploy these to educational FPGA boards such as the Digital System Development Board (DSDB). Multisim’s Programmable Logic Device (PLD) schematic, along with support for leading Digilent teaching hardware allows students to put the fundamentals of digital theory into practice. To get you going, you could just use your switches straight from VCC to the Anode (through current limiting resistor).Taking a hands-on approach to learning digital logic can be difficult without the need for students to learn complex hardware descriptive languages. With the emitter joined to VCC and the collector to your display Anode through a small resistor then current will flow from VCC through the PNP transistor to the display Anode. You could let the 74LS138 outputs drive a PNP transistor so that when it's output goes low it pulls current from the base (through a resistor, say 1K). As your displays are Common Anode this is correct for the 74LS47, but the 74LS138 is incorrect, as you need to SOURCE current to the Anode of the displays. switch open = '1'.Ģ) Both of your driver ICs are of the type that SINK current, ie when the input in ON it looks like a swicth to GND. Note, this ends up as opposite logi, ie switch closed = '0'. Your switch then switched that input to ground. For TTL logic, you need to pull each input High to VCC with a 4K7 or similar resistor. There are several problems with this circuit.ġ) Your switched don't connect to anything on one side so they cannot possibly do anything.
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