Litaba

Ho sebetsa le lik'homphieutha tsa khale hangata ho thata hobane ha li lumellane le lisebelisoa tsa morao-rao. Haeba u hlokometse hore litheko tsa li-TV tsa khale tsa CRT (cathode ray tube) le li-monitor li nyolohile morao tjena, u ka leboha sechaba sa lipapali tsa retro le lik'homphieutha tsa retro. Ha se feela hore lits'oants'o tsa maemo a tlase li shebahala li le betere ho li-CRT, empa lits'ebetso tse ngata tsa khale ha li khone ho hlahisa video e amohelehang ho li-monitor tsa sejoale-joale. Tharollo e 'ngoe ke ho sebelisa adaptara ho fetolela RF ea khale kapa lets'oao la video le kopaneng hore e be lets'oao la sejoale-joale. Ho thusa ho nts'etsopele ea li-adapter tse joalo, dmcintyre e thehile sebui sena sa video bakeng sa li-oscilloscopes.
Ha e ntse e fetolela video, dmcintyre e ile ea kopana le bothata moo chip ea video ea TMS9918 e sa kang ea baka boholo ka ts'epo. Sena se etsa hore ho be thata ho sekaseka matšoao a video, a tla hlokahala ho ba lekang ho a fetola. Li-chips tsa Texas Instruments TMS9918 VDC (Video Display Controller) li tumme haholo 'me li sebelisoa lits'ebetsong tsa khale tse kang ColecoVision, MSX lik'homphieutha, Texas Instruments TI-99/4, joalo-joalo. Video ena ea trigger e fana ka li-bandwidth tsa video tse kopantsoeng le interface USB bakeng sa oscilloscopes. . Khokahano ea USB e u lumella ho nka li-waveform ka potlako ho li-oscilloscopes tse ngata, ho kenyeletsoa le li-oscilloscope tsa dmcintyre's Hantek.
Potoloho ea "video trigger" hangata e na le li-circuits 'me e hloka li-circuits tse' maloa tse kopantsoeng: microchip ATmega328P microcontroller, 74HC109 flip-flop, le LM1881 video sync splitter. Likarolo tsohle li rekisoa ho boardboard e tloaelehileng. Hang ha khoutu ea dmcintyre e se e kentsoe ho ATmega328P, ho bonolo haholo ho e sebelisa. Hokela thapo ho tloha ho sistimi ho ea ho Video Trigger input le thapo ho tsoa ho Video Trigger e hlahisoang ho sebali se lumellanang. Ebe o hokahanya thapo ea USB ho kenyelletso ea oscilloscope. Beha sebaka sa ho qala moeling o latelang o ka bang 0.5V.
Ka setup sena, joale u ka bona lets'oao la video ho oscilloscope. Ho tobetsa sekhouto sa rotary ho sesebelisoa sa ho bulela video ho totoba lipakeng tsa moeli o nyolohang le o theohang oa lets'oao la ho qala. Fetolela khouto ho tsamaisa mohala oa trigger, tobetsa 'me u tšoare encoder ho seta mohala oa trigger ho zero bocha.
Ha e hlile ha e etse phetoho ea video, e lumella mosebelisi ho sekaseka lets'oao la video le tsoang ho chip ea TMS9918. Empa tlhahlobo e lokela ho thusa batho ho theha li-converter tsa video tse tsamaellanang ho hokela likhomphutha tsa khale ho li-monitor tsa sejoale-joale.