Page 200 - Making PIC Microcontroller Instruments and Controllers

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l !16 cou flNG PULSES: PROGMMMABLE

5 VOLTS

220 OHMS

PHOTO

1 [4EG

Flgure 15;7. A common anode seven-segment
display.

One way oflaliDg oul the circuitry for a common anode four-chaBcter display would
beas shown in Figurc 15.8. Wcwould use a conliguouspoft to connect to the eight seg
mentliics and a halfpol1 (lbr lhc four units in ourcase) !o select the display to be lighted
r. tr rir.l<. -ga n In rltid .u\(e.sior,.
u.ing on( rinF
As nrcnlioned earlier the comrnon line is the common anode (+). Thc connections
and the progfan code that conlol the segments mun bs adjnsted to suil the devices
selected. Even though we did wire il. wc will ignorc the dccimal point for this pariiclr-
lar application. Howcvcr, \\Je will test it to make sxfe it works
llow the data lines arc wlred (the wirirg sequcnce) is not important because whal
everis nceded for the display desired can be describcd in the software and does not nrke