|
|
|
|
Hi
i see that the HW simul. dont let me connect some internal chim outpit to several gate inputs
for example - on ALU:
Mux4Way16(a=xandy ,b=xaddy ,c=nxandy ,d=nxaddy , sel[1]=no ,sel[0]=f ,out=out );
Mux4Way16(a=xandy ,b=xaddy ,c=nxandy ,d=nxaddy , sel[1]=no ,sel[0]=f ,out[15]=ng , out[0..14]=zrox );
since ng bit is driven fron the ALU output simply by looking on the msb,
i expected it to be possible to just "daw a line" to that output pin
is tead i m expected to use agin the mux, isnt that wast of resources?
is there another way?
regarrds
|
|
Administrator
|
ysh443 wrote
i see that the HW simul. doesn't let me connect some internal chip output to several gate inputs
for example - on ALU:
Mux4Way16(a=xandy ,b=xaddy ,c=nxandy ,d=nxaddy , sel[1]=no ,sel[0]=f ,out=out );
Mux4Way16(a=xandy ,b=xaddy ,c=nxandy ,d=nxaddy , sel[1]=no ,sel[0]=f ,out[15]=ng , out[0..14]=zrox );
since ng bit is driven from the ALU output simply by looking on the msb,
i expected it to be possible to just "draw a line" to that output pin
See example in Appendix A.5.3. You can do this all in one statement.
--Mark
|
|
|
Hi Mark
sorry for my typo errors
i understand the sub-bussing technique
yet
on the appendix:
Output Pins Each output pin of a part may feed one of the following destinations:
* an output pin of the chip
* an internal pin
so, internal output can be wired only once
and the example code i previously attached , shoe that i had to use the same combinatorical for outputing the ALU function output
and again use the same wasty comb. to create the ng pin
even if i had sub-bussed it, i still was missing the output msb
regards
|
|
|
What Mark is saying is that your two lines of code imply that you have two Mux4Way16 chips, and your intent seems to indicate that you really only want the one.
Mux4Way16(a=xandy ,b=xaddy ,c=nxandy ,d=nxaddy , sel[1]=no ,sel[0]=f , out=out, out[15]=ng, out[0..14]=zrox);
|
|
|
you are right
so there is no shorter ot slimmer immplementation way to do it?
|
|
Administrator
|
ysh443 wrote
on the appendix:
Output Pins Each output pin of a part may feed one of the following destinations:
* an output pin of the chip
* an internal pin
The quote from the Appendix A is incorrect. It should read "may feed one or more of".
You do not need two muxes; what ybakos wrote is correct HDL and is accepted by the Hardware Simulator.
ybakos wrote
Mux4Way16(a=xandy ,b=xaddy ,c=nxandy ,d=nxaddy , sel[1]=no ,sel[0]=f , out=out, out[15]=ng, out[0..14]=zrox);
--Mark
|
|
Locked
