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qbancoffee / imac_g3_ivad_board_init

iMac G3 IVAD board initialization with an arduino
GNU Lesser General Public License v3.0
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Imac G3 Timings? #7

Closed StrikerMan780 closed 3 years ago

StrikerMan780 commented 3 years ago

I am wondering, what are the display formats/timings for the Imac G3? I have a device that takes custom timings, and I want to capture the G3's VGA-Out. Figured you might know this. (I'm specifically trying to capture the 640x480, 117hz mode.

qbancoffee commented 3 years ago

Sounds like fun.

Well, the iMac G3 supports 3 resolutions.

1024x768 @ 75 Hz <---standard timings. 800x600 @ 95 Hz 640x480 @ 117 Hz

This is what I get when I decode the EDID used in the sketch

Manufacturer: APP Model 9d05 Serial Number 16843009 EDID version: 1.1 Analog display, Input voltage level: 0.7/0.3 V Sync: Separate Maximum image size: 27 cm x 20 cm Gamma: 2.50 DPMS levels: Standby Suspend Off RGB color display Established timings supported: 1024x768@75Hz Standard timings supported: Detailed mode: Clock 50.000 MHz, 270 mm x 200 mm 640 656 720 832 hborder 0 480 481 484 514 vborder 0 +hsync +vsync Detailed mode: Clock 62.400 MHz, 270 mm x 200 mm 800 816 896 1040 hborder 0 600 601 604 632 vborder 0 +hsync +vsync Monitor ranges (GTF): 75-117Hz V, 60-60kHz H, max dotclock 80MHz Monitor name: iMac Checksum: 0xc9 (valid) EDID block does NOT conform to EDID 1.0! Has descriptor blocks other than detailed timings EDID block does not conform at all! Bad year of manufacture

Have you used cvt or gtf to get that sort of info?

I hope that helps.

StrikerMan780 commented 3 years ago

here's an image of the current timings I'm using. The picture is mostly correct, but I have a bunch of flickering garbage at the right-side of the screen, the last column of pixels being skipped:

image

Is this wrong?

qbancoffee commented 3 years ago

Oh sorry , I somehow missed this. I'll check it out when I get home.

qbancoffee commented 3 years ago

its close to what is in one of the edids I use.

try these values. The first column is what you want

timings