Post by thread:Newbie Counter Question *non pic related*

Hi.. *I have a non PIC related question. * For class project.. I had to build a simple modified binary up/down counter from a 74193 IC that counts from 0 to 10 and repeats. (Yea I know it sounds simple huh? Well I'm new to digital) Now being so fascinated by how that works.. and for extra credit, I have to come up with with a way to make the counter count from 0 to 10, then from 10 back to 0 and keep cycling and I have only the following to use: 74193 binary counter and/or/nand/nor gates j-k flip flops If someone could kindly steer me in the right direction, I'd really appreciate it. - tony

I'm sure there are lots of people on this list, including myself, who are willing to help with your problem, but I often wonder, who deserves the 'extra credit' ;-) Anyway. I haven't tested this but it may help you out. To detect a zero count, connect 2 OR gates to 193 Qa, Qb, Qc, Qd. The outputs from these gates is connected to a NOR gate. This then gives a logic 1 when a count of 0 is reached. To detect a 10 count, connect an AND gate to 193 Qb and Qd. When a count of 10 is reached a logic 1 is produced. The output from the NOR gate and the AND gate are connected to another OR gate and the output from this gate is connected to the Clk input to a JK Flip Flop. The J input is tied Hi, and the K input is tied low to toggle the FF output on positive clock pulses. The FF Q output is connected to The Up pin on the 193. The FF Q bar output is connected to the Dn pin on the 193. Thus when a count of 0 or a count of 10 is reached the JK FF will toggle and change the count state on the 193. I just thought of this off the top of my head, so you may need to experiment a bit. The JK FF has some extra inputs for you to connect, but these are explained in the data sheet, and don't forget about leaving unused gate inputs floating. Thats a no no, although TTL will pull high if left disconnected. Tony PicNPoke Multimedia 16F84 Beginners PIC Tools. PicNPoke - PicNPlay - PicNPlan - PicNPrep - PicNPost PicNPort - Plus DT type saver. New addition - PicNQuiz. http://www.dontronics.com/picnpoke.html

At 18:57 1998-03-18 EST, you wrote: >Hi.. > >*I have a non PIC related question. * > >For class project.. I had to build a simple modified binary up/down counter >from a 74193 IC that counts from 0 to 10 and repeats. (Yea I know it sounds >simple huh? Well I'm new to digital) Now being so fascinated by how that >works.. and for extra credit, I have to come up with with a way to make the >counter count from 0 to 10, then from 10 back to 0 and keep cycling and I have >only the following to use: > >74193 binary counter >and/or/nand/nor gates >j-k flip flops > >If someone could kindly steer me in the right direction, I'd really appreciate >it. > > >- tony Use a PIC and write "74193" on top of it! ;) Wel:, dont cheat, work on further with open mind. /Morgan / Morgan Olsson, MORGANS REGLERTEKNIK, SE-277 35 KIVIK, Sweden \ \ spam_OUTmrtTakeThisOuTiname.com, ph: +46 (0)414 70741; fax +46 (0)414 70331 /

At 18:57 1998-03-18 EST, you wrote: >Hi.. > >*I have a non PIC related question. * > >For class project.. I had to build a simple modified binary up/down counter >from a 74193 IC that counts from 0 to 10 and repeats. (Yea I know it sounds >simple huh? Well I'm new to digital) Now being so fascinated by how that >works.. and for extra credit, I have to come up with with a way to make the >counter count from 0 to 10, then from 10 back to 0 and keep cycling and I have >only the following to use: > >74193 binary counter >and/or/nand/nor gates >j-k flip flops > >If someone could kindly steer me in the right direction, I'd really appreciate >it. > > >- tony Use a PIC and write "74193" on top of it! ;) Wel:, dont cheat, work on further with open mind. /Morgan / Morgan Olsson, MORGANS REGLERTEKNIK, SE-277 35 KIVIK, Sweden \ \ .....mrtKILLspam@spam@iname.com, ph: +46 (0)414 70741; fax +46 (0)414 70331 /

Well Tony I didn't understand one thing, do you want it to count 0,1,...,10,0,1 or up and down 0,1,...,9,10,9,8,...1,0,1,2,... and so on. Or do you nedd both. If you want to count up continues ...9,10,0,1,.. you just have to detect 10 and them (using AND gates again) direct 1 clock pulse to the MR pin instead of the clock up. The switching of the clock bettwen clock up and MR can be obtained just combining logic gates, you dont even need a F/F. But if you want it to be synchronus (less sensitive to noise and to propagation delays) you can set up a F/F with the J/K inputs activated by the detection logic and clocked in the oposite fase of the counter clock. In the other option, you have to do is to detect when it as reached 10. In that situation you switch the clock pulse to de oposite direction (the chip as separate up and down clocks), them when it reaches 0 you switch again. The switching is obtained using two AND gates to control the clock and o ne F/F to select the state UP or DOWN. You conect the J to 0 detection circuit and the K to 10 detection circuit and clock in opposite fase to the counter. The clocking of the F/Fs in oposite fase is to make sure that they switc h state in bettwen counting clocks. As the counter clock are positive logic (rising edge) you make sure the F/Fs have negative logic clocks or else feed them with an inverted clock. Hope theis helps. Best of luck Jorge F PS: I'm not in favour of doing someone elses school works, because that someone else becomes the looser of the tale. But I don't mind giving some directions and warning for possible pitfals. At 08:47 98.03.19 +0100, you wrote: {Quote hidden}>At 18:57 1998-03-18 EST, you wrote: >>Hi.. >> >>*I have a non PIC related question. * >> >>For class project.. I had to build a simple modified binary up/down counter >>from a 74193 IC that counts from 0 to 10 and repeats. (Yea I know it sounds >>simple huh? Well I'm new to digital) Now being so fascinated by how that >>works.. and for extra credit, I have to come up with with a way to make the >>counter count from 0 to 10, then from 10 back to 0 and keep cycling and I >have >>only the following to use: >> >>74193 binary counter >>and/or/nand/nor gates >>j-k flip flops >> >>If someone could kindly steer me in the right direction, I'd really >appreciate >>it. >> >> >>- tony > >Use a PIC and write "74193" on top of it! ;) > >Wel:, dont cheat, work on further with open mind. > >/Morgan >/ Morgan Olsson, MORGANS REGLERTEKNIK, SE-277 35 KIVIK, Sweden \ >\ mrtKILLspaminame.com, ph: +46 (0)414 70741; fax +46 (0)414 70331 / > =============================================================== cumprimentos / best regards Jorge Ferreira //.....jorgegfKILLspam.....mail.telepac.pt ------ Make sure brain is in gear before engaging mouth ------- ===============================================================