Talata na Gudanar da Kula da Muhimmancin Sensor na Kamera na RK3576: Wadanda Babu Zama Amsa Kafin Samun Tashin Hardware

Don zaɓar firikwensin kyamara da ƙirar kayan aiki akan dandamali na RK3576, dole ne a kammala mahimman bayanai da yawa kafin fara aikin zane. Wadannan yanke shawara kai tsaye shafi imaging yi da hardware zane yiwuwa.

RK3576 Ƙuntatawa na CSI/PHY da ISP

RK3576 yana ba da tsarin haɗin kyamarar mai sassauƙa, amma ana buƙatar tsara tsari a kusa da bukatun aikin tun daga farko.

Tallafin Interface: SoC yana tallafawa duka MIPI CSI-2 da DVP kyamarar kyamarar, tare da MIPI CSI-2 yana ba da babbar fa'ida ga ƙirar yanzu.

RK3576 yana samar da hanyar C / D-PHY guda ɗaya tare da hanyoyi huɗu, da kuma hanyoyin D-PHY guda biyu. Za a iya daidaita albarkatun PHY da ake da su a matsayin tashoshin D-PHY guda hudu ko tashoshin D-PHY guda hudu. Wannan ya sa zane-zane da yawa na kyamara, gami da tsarin ra'ayi da yawa da ake amfani da su a cikin tsaro da aikace-aikacen robotics.

Lura:

• Don zane mai kyamarori da yawa, sanya PHY da albarkatun layi a farkon. Mai sa ido guda ba zai iya ɗaukar PHYs biyu ba.
• Wani yanki na RK3576 CSI ya zama iya rarraba a matsayin C-PHY ko D-PHY. A cikin yanayin D-PHY, yana iya kawo 4.5 Gbps ga kulle lane; a cikin yanayin C-PHY, yana iya kawo 2.5 Gsps ga kulle trio. Wadanda daga cikin wadanda D-PHY channels suna iya kawo 2.5 Gbps ga kulle lane. Wani rarraba na hardware mai kyau yana bukatar kuwa 20% na bandwidth a gaba daya. Idan yadda bayanai suka ci gaba ko suka tashi kamar yadda interface ta nemo, kuma bayanai masu fuskantar, bayanai masu kuzo, da sauran alalubabai na bayanai suna zama mafi kyau.
• SoC din yana iya kawo parallel DVP camera interface don wadanda sensors na farko da wadanda suka ci gaba da karami. Saboda DVP da MIPI suna share some pins, yanzu na pin assignment yana bukatar kuwa a farko don bincike in ba a yi shi a farko kuma don bincike in ba a yi shi a farko.

RK3576 ISP Specifications da Processing Limits

• RK3576 yana da ƙaramin hardware ISP wanda ya sa kuma aiki ne don fassara taswira ta hanyar 16 MP kuma HDR dynamic range ta hanyar 120 dB. Amma a tsari na kamarai mai yawa, yadda ake buga raw streams manya a cikin ISP yana nufin cewa resolution na kamarai da frame rate na muhimci suna daga cikin kudin ISP da MIPI CSI-2 receive bandwidth.

Misali na tsari na kamarai mai yawa: 1 x 8 MP (4K a 30 fps) + 2 x 2 MP (1080p a 30 fps).

• Tsari na kamarai mai yawa suka bukatar karin gano na farko akan frame synchronization. Kamarai na multi-view da stereo ranging zasu bukata hardware VSYNC synchronization. Ku duba idan hardware synchronization zai shiga aiki kuma idan SoC yana da kudin external trigger pins wanda ke cikin yadda kamarai suka bukata.

Takardun tattaunawa na sensor

• Fassarar interface da mode: Duba MIPI CSI-2 ko DVP, kuma MIPI lane count (1, 2, ko 4 lanes).
• Formatin lissafi: A cikin platformi na RK3576, inganta na VICAP ta so RAW, RGB888, da wasu formatin YUV. ISP mai tsaya a cikin jihadi ya amfani da bayanan RAW kuma ya saha su zuwa YUV don karamar tarihi na gaba. Bayanan RGB da YUV wadanda aka saba su daga baya ba su tashi a cikin ISP ba.
• Gurba da shakara na fari: Ku duba bukatar kowane sensor na gaba, sannan ku tabbata mode na amfani wadanda aka saha su ne a lokacin da kowane kamera ta yi amfani ta hanyar yadda ke aiki. Kowane abin da aka yi dole ya kasance a cikin kudin ISP na amfani a lokacin da ke ciki.
• Kamfanibi na gaba: Wani sensor mai amfani da yawa yana amfani da uku shugaban kudin: AVDD don ƙirƙirin na analog, DVDD don ƙirƙirin na digital, da DOVDD don darajar I/O. RK3576 MIPI PHY yana amfani da shugaban kudin mai tsayi 1.8 V, don haka shugaban kudin DOVDD na sensor da ke cikin 1.8 V yana da faida. Idan darajar DOVDD na sensor ba ta dace da darajar I2C I/O na host ba, za a iya sanya level shifter a kan bus na kontrolin mai yawa. Kada a sanya level shifter na gaba a kan signals na MIPI mai yawa da farko. Hardware ya kamata ya segu tsari na pambu da kusurin na sensor. Sauran sauran na software suna taka kuma a cikin wannan tsari; idan an yi waɗannan lokaci ba tare da kyau ba, zai iya bincika sensor ko kuma zai iya samun hoton. Zamu iya koyon kudin mai yawa a cikin AVDD, DVDD, da DOVDD don haka kowane LDO a cikin hardware ya kashe abu ne da yawa da kuma ya kashe abu ne da yawa.
• Kontrol bus: Tabbata cikakken I2C na sensor. Don sistema mai kamarawa ta camera, rarraba yadda za a biyayi addinin da suka dace, ko ta hanyar canza addinin a software idan aka sanya amfani da shi ko ta hanyar amfani da I2C switch na gaba'aya.
• Ingantaccen sa'at: RK3576 ta ba da mahaulluka na sa'at na sensor MCLK da suka dace a cikin kari. Kullum sa'at ana samunsa daga sa'at na SoC na gaba'aya kuma ana baiwa shi zuwa sensor ta hanyar GPIO mai kamarawa; kullum output zai iya an ba shi karfi ko an rarrabawo shi a cikin kari. Rano na software na dace don sa'at na MCLK ita ce 6 zuwa 48 MHz. Idan sensor ya bukata sa'at da ke cikin wannan rano, amfani da oscillator na gaba'aya ta hanyar wajibi. Ana kuma bukatar tabbatawa sistemai mai kamarawa ta camera don kuskuren da suka dace a cikin pin-multiplexing.
• Sukar da design na tsinku: Sensorai da yawa da kamarawa da yawa da sa'at suna ci gaba yawan sukara. Tabbata jijjilin sukara na board da tsinkun bayanin abin da ke cikin kari kafin hardware ta dace.
• Kontroli na lens, filter na IR-cut, da kuma illuminator: Tabbata ku cewa akwai wani abu na GPIO wanda ke cikin gaba daya don hankali daga cikin wadannan abubuwan da suka bukatar shi don amincewa da kowane actuator da driver.
• Kamfanin HDR: RK3576 yana da amfani da DOL HDR, staggered HDR, da kuma multi-frame HDR. A cikin lokacin da za ku zaharci sensor, tabbata ku cewa format na bayanan HDR da kuma lokaci na yanci suna da kamfanin da ISP da VICAP na RK3576.

Idan yake muna iya, fara da sensor wanda aka san shi ne da platform community ko kuma da supplier na module. Wannan zai iya gyara karin yadda za a yi driver-development da kuma karin yadda za a sanya shi a cikin gaba.

Wadannan sensors suka kashe musu da kuma suka haɗa da Sony IMX415 (8 MP), IMX566 (8 MP), IMX678 (8 MP), IMX464 (4.1 MP), da IMX662 (2 MP), kuma onsemi AR0234 (2.3 MP) da OMNIVISION OG02C1B (2 MP). Idan project na ku ke bukatar sensor na farko, tatta kun taƙaita [email protected] don talk about custom integration da kuma tuning.

Muhimmancin Bayanai don PCB Design

• MIPI CSI routing: Tsoho differential impedance zuwa 100 ohms +/-10%. Jika P/N length mismatch a cikin kowane differential pair ta zama ƙasa da 5 mil, kuma jike lane-to-lane mismatch a cikin wanda CSI port ta zama ƙasa da 200 mil. Rute MIPI signals daga high-speed clocks, DDR, da high-current power traces. Ba a rute su daga splits a cikin reference plane ba. Jika traces ta zama ƙasa da yawa, yayin da aka fahimta ƙasa da 15 cm; duk da yawa ne route, duk da ƙasa ne maximum data rate wanda za a iya amfani da shi da kyau.
• MCLK shine high-speed single-ended clock ce. Jika spacing daga MIPI differential pairs kuma kara gafara long parallel runs don rage crosstalk.
• Jika high-speed MIPI routes daga strong noise sources kamar switching power supplies da DDR buses, kuma bari sound shielding da grounding idan layout ya nemo shi.
• Filtarar amfanin: Sanya 0.1 uF da 1 uF decoupling capacitors cikin kusurwar sensor supply pin. Zai iya sanya ferrite bead a cikin AVDD don gudanin analog rail daga digital-circuit noise.
• Sensors na high-resolution wanda suka yi amfani da high frame rates zai iya samun amfanin matukar yawa. Yanzu na sarrafa zai iya zama babu kuma yana saita color shift, don haka thermal solution zai iya tabbatarwa a lokacin hardware design ba a lokacin bayan bring-up ba.
• Tabbatar da pin-multiplexing: Tabbatar da dukkan MIPI, DVP, I2C, MCLK, da GPIO assignments don shared-function conflicts.

Software da Image-Processing Pipeline

• Hardware acceleration: RK3576 ya kashe RGA 2D graphics accelerator don amfani da operations kamar image-format conversion (misali, YUV zuwa RGB), scaling, da rotation. Amfani da RGA ba tare da CPU-based processing zai iya rage CPU load da yawa kuma yana mahimmanci don samun stable high-frame-rate operation, misali 1080p a 30 fps.
• NPU data-flow planning: Idan ai model ya shiga a cikin RK3576's integrated 6 TOPS NPU, wani yadda mai kyau shine camera capture, ISP processing, RGA format conversion da scaling, NPU inference, da display output. Latency a kowane yanki zai kwafuwa a lokacin system design don ganin cewa abu na gaba daya ya dace da real-time target na sa.

Wadannan reference configurations sun nuna yadda kowane camera interface za a iya amfani da su don wadannan applications na farko.