Anyone know how to instantiate ( in Viewdraw ) a bus with a fixed value?
I try to explain better: if for example I have to add the constant decimal value 7 to an incrementer every time I have a rising clock event, I suppose I have to enter in the incrementer with a 4-bit wide bus which holds the value 7 every time.
How can I do it??
As you see I'm very new with fpga programming, any help is very appreciated.
Thanks in advance, Teo.
There are several ways to do this. The simplest is this:
Place the following 4 symbols on your schematic:
GND VCC BUF BUF
Connect the GND to a BUF input. Connect the VCC to a BUF input.
Place a net stub on the outputs of each of the BUFs
Label the net on the output of the BUF that has its input connected to GND: "L" Label the net on the output of the BUF that has its input connected to VCC: "H" (obviously, don't include the quote characters)
If for example you have an 8 bit adder, you can now place a bus stub on one of its inputs. Label this bus stub
L,L,L,H,L,L,H,L
And you will get the HEX constant 0x12, which is 18 decimal.
Philip
=================== Philip Freidin snipped-for-privacy@fpga-faq.com Host for
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