Great minds think alike!If you are planing on using a multiplexed display a variation on the EPROM idea would be to connect the 8 input bits to address lines 0 to 7 and a multiplexing counter (which counted to 3 or 4 for the multiplexing.) connected to address lines 8 and 9. You would only use 4 data output bits from the EPROM and connect these to the inputs of a 7 segment decoder.
So each multiplexing time slot only needs to output one digit. So each of the three areas of the EPROM (Selected by A8 and A9) would only contain the information for one digit. (Units, tens, hundreds.). You could even dispense with with the 7 segment decoder if you used 7 output bits from the EPROM and programmed the EPROM with the 7 segment patterns rather than the decimal digits.
I started using 32x8 PROMs in the mid 70's and there were no LS parts. When I searched, I only saw one URL to it and you had to join to download the datasheet. I passed...Cheers for that.... I thought I heard it somewhere..
Funny though.. A quick google lists 74LS185...
You can make your own using 8x32 PROMs; 8 bits would require 3 of them. If you were tempted to go that route, you should just program an EPROM with a 16 bit output. In the thread I referenced earlier, I programmed one to do 4 BCD digits.Where would you purchase the 74LS185's
|Thread starter||Similar threads||Forum||Replies||Date|
|B||Need help indentifying a component.||Datasheets, Manuals & Parts Identification||28|
|L||Need Help Finding Output Frequencies for Two 4-Bit Binary Counters||Homework Help||3|
|M||I need help about Binary and BCD counter||Analog & Mixed-Signal Design||7|
|M||I need help about Binary and BCD counter||Analog & Mixed-Signal Design||0|
|A||Binary Clock: First Timer, need Help & look-over!||General Electronics Chat||15|
by Jake Hertz
by Dale Wilson