INDIANA UNIVERSITY, DEPT. OF PHYSICS, P400/540 LABORATORY FALL Laboratory #10: Integrated Up-Down Counters and Displays

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1 INDIANA UNIVERSITY, DEPT. OF PHYSICS, P400/540 LABORATORY FALL 008 Labratry #10: Integrated Up-Dwn Cunters and Displays Gal: Use an integrated up-dwn cunter, lad in values, use in circuitry. Implement a useful LED display t readut the cntents f the utput bit lines. 1. Set up Yu will need the array f 8 slide that yu will use t lad data bits. Cnnect each ne t a pull up resistr f value between ~100-00kΩ as shwn belw. Yu are als ging t use ne f the debunced push-buttns with a pull-up resistr as yu did in last lab, plus ne f the single-ple, duble-thrw () slide cnnected t and grund. 1 0 Pull-up resistr T data. Integrated 4-Bit Cunter This 4-bit cunter includes mst f the features standard t integrated cunters, plus a few that are less standard: It cunts up r dwn, and that will be handy later n. It includes three-state utputs and this feature will allw it t be tied directly t a bus. It can be "laded" with an initial value. Tday, we will use this feature t make a divide-by-given-number cunter. It includes a carry-in and carry-ut pin that makes "cascading" these chips easy, s as t frm a bigger cunter. We will cascade tw 's t frm an 8-bit cunter. Cnnect the belw. Wrking thrugh the meaning and what t d with each pin: D0, D1, D, D3 = fur input data bits. Supply these frm fur f the slide. Keep the least significant bit (D0) t the right as by cnventin. Q0, Q1, Q, Q3 = fur utput data bits (three-state). At first, send these t fur f the LEDs, keeping the least significant bit (Q0) t the right. = clck. At first, supply this manually with the debunced pushbuttn. Later, cnnect t the TTL utput f the breadbard scillatr.

2 OE = utput enable, asserts lw, s tie t grund. Cin = carry-in, als "cunt enable trickle input", CET. Cut = carry-ut, als "terminal cunt utput" (TC) U/D(bar) = up/dwn. Cunter will cunt up with this set HIGH, will cunt dwn if grunded. LD = lad, r "parallel enable input" (PE). When the cunter is cunting, set t. When yu want t lad a specific string f bits int the utputs, set the slide switch inputs mve this t GND, and allw at least ne clck cycle. CEP = "cunt enable parallel input" is active LOW, s tie t grund. MR, SR = "master reset input", and "synchrnus reset input". These are all active LOW, s tie them all t. Output fur bits, cnnect t fur LEDs r numerical display Frm debunced pushbuttn (with pull-up resistr) r breadbard scillatr 17 OE CIN CEP MR SR 4-bit cunter Q0 Q1 Q Q3 D0 D1 D D3 cnnect t 4 f the 8 slide V CC = pin 0 = GND = pin 10 Nrmally when cunting, set t GND when lading Di Wire the chip as shwn. First manually clck the chip using the pushbuttn and bserve the utput at the LED's and write dwn the bit pattern. Is it behaving as expected? Cnnect U/D(bar) t grund instead. Nw clck it manually and bserve and describe the behavir. Cnnect U/D(bar) back t t set back t "cunt-up" mde. Nw try lading a number directly int the utputs: Set LD t grund using the slide switch. Asserting LD makes the cunter behave like a register f 4 D-type flip-flps rather than a cunter. On the next clck, the '569 lads its 4 flip-flps with the data at its 4 inputs. Nw bserve the effect f changing the slide input, and what happens when yu set LD back t t allw cunting again.

3 3. Add a display The display chips that yu will nw install d quite a lt. They are nt simply 7- segment LED displays. They include: the LEDs (many mre than 7 segments, 0 little dts instead); a decder that translates the 4-bit input int the lighting f the apprpriate LEDs; a 4-bit latch; and a blanking functin. Each display will shw the hexadecimal character (0 thrugh F) that crrespnds t the 4-bit value fed t it. Send the Q0...Q3 bits t the LED display with the cnnectins belw: Tw ntches at tp 1 Vcc1 Vcc 14 Q1 D1 D 13 Q Q0 3 D0 D3 Q3 4 DPL 5 LE DPR 10 7 GND BL 8 Other inputs include: DPL, DPR = left and right decimal pints; LE = latch enable; BL = blank input, blanks the display if HIGH. Repeat the activities f the previus sectin using ne f these display chips. If it is nt cunting in crrect rder, yu very likely have mixed up the data inputs. Nw replace the manual push-buttn giving the clck signal with the TTL utput f the breadbard scillatr (stay in the "Hz" range). Change the frequency and bserve the change in cunt rate. Shw me the circuit wrking.

4 4. Cascaded 8-bit cunter The is easy t cascade as IC cunters usually are: yu just need t cnnect Cut f ne stage t Cin f the next. Yu culd keep ding this almst indefinitely (except fr the accumulatin f carry delays if yu made the chain very lng). Try this ut, cascading a secnd '569. Cnnect a secnd display chip t the secnd chip. V CC = pin 0 = GND = pin 10 T LS Hex Display T MS Hex Display Q4 Q5 Q6 Q7 17 OE CEP MR SR Q0 Q1 Q Q3 17 OE CEP MR SR Q0 Q1 Q Q bit cunter D0 D1 D D3 4-bit cunter D0 D1 D D3 cnnect t 4 f the 8 slide D4 D5 D6 D7 cnnect t 4 f the 8 slide Nrmally when cunting, set t GND when lading Di Check ut its peratin as befre, i.e., cunting dwn, cunting up, and lading a data string (but nw 8 bits!). Shw me the circuit wrking. 5. Mdulus-N Cunter "Mdulus" is just the number at which the cunter "starts ver". In its default versin, the 4-bit cunter is mdulus-16 (starts ver when it reaches decimal 16), while the 8-bit ne is mdulus-56. With a few clever mdificatins, yu can have yur cunter cunt dwn frm any given 8-bit number (set at the slide ) and then start ver when gets dwn t zer. Make the changes as shwn. Turn the device int a cunt-dwn cunter. Cnnect Cut(bar) t LD. With these tw tied tgether, the signals are asserted nly when the cunter is abut t "rll ver". Since the cunter is set t cunt dwn, it relads each time that it hits zer. This circuit thus lets the slide set the perid and frequency f the Cut(bar) pulse wavefrm.

5 V CC = pin 0 = GND = pin 10 T LS Hex Display T MS Hex Display Q4 Q5 Q6 Q CEP MR SR Q0 Q1 Q Q3 17 CEP MR SR Q0 Q1 Q Q3 OE OE 4-bit cunter D0 D1 D D3 4-bit cunter D0 D1 D D3 cnnect t 4 f the 8 slide D4 D5 D6 D7 cnnect t 4 f the 8 slide 6. Primitive Electrnic Stp Watch Restre the cunter t the state that it was in Sectin 4. Cnfirm, first, that yu can start and stp the cunter by taking Cin(bar) lw, and then high, using a manual switch. Then set the input slide t 00 and check that yu can clear the cunters by taking LD(bar) lw (while the clck is running). Yu nw have a primitive stpwatch! Display 8 Q OSC 11 LD cunters D 8 Input slide Nrmally when cunting, set t GND when lading Di

6 7. Future Keep this circuit wired up. The stpwatch can becme a perid meter if we add the autmatic utput-latching and cunter-clearing mentined abve. Yu can time the duratin f time that yu hld Cin(bar) lw t micrsecnds with a fast enugh clck.it will then be pssible t als be use yur "duble-barreled ne-sht" built in the previus lab t make a digital capacitance meter.