BRT Community
General Category => Discussion - EVE => Topic started by: JeffC on July 14, 2020, 03:40:49 PM
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The website says the FT813 can drive 800x600 displays. Once I go through the datasheet I see little or no mention of the 800 pixel width limitation anymore. 854x480 (FWVGA) has fewer total pixels than 800x600. So could the FT813 drive a FWVGA display ? Or would the extra 54 pixels simply be black ? Thanks a lot!
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Hello,
The EVE series of ICs do not include a frame buffer, they dynamically clock out each computed pixel on the screen. A displays size and what the Pixel Clock is running at will determine the achievable performance. It is possible to run EVE at higher resolutions, but this will result in a slower refresh rate for the screen.
If we take a working example from the following WQVGA settings:
// WQVGA display parameters
lcdWidth = 800; // Active width of LCD display
lcdHeight = 480; // Active height of LCD display
lcdHcycle = 928; // Total number of clocks per line
lcdHoffset = 88; // Start of active line
lcdHsync0 = 0; // Start of horizontal sync pulse
lcdHsync1 = 48; // End of horizontal sync pulse
lcdVcycle = 525; // Total number of lines per screen
lcdVoffset = 32; // Start of active screen
lcdVsync0 = 0; // Start of vertical sync pulse
lcdVsync1 = 3; // End of vertical sync pulse
lcdPclk = 2; // Pixel Clock
lcdSwizzle = 0; // Define RGB output pins
lcdPclkpol = 1; // Define active edge of PCLK
HCYCLE = 928
VCYCLE = 525
VCYCLE * HCYCLE = 487,200
Note: REG_PCLK is using the value 2 which will divide the clock down to 30Mhz (assuming system clock of 60Mhz).
Result = 30,000,000/487,200 = ~ 61 fps
In short, yes EVE can drive a FWVGA display, you would just achieve a slightly slower refresh rate than using a WVGA display for example.
Best Regards,
BRT community
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Are you trying to upcycle a Smartphone or Beamer display?
Please provide a datasheet link to such a display.
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Thanks for the quick replies.
@BRT Community: If I take your example, which had a horizontal 'overhead' (porch I guess) of 128 clocks and a vertical overhead of 45 clocks, that would roughly compute to 30,000,000 / (854+128) / (45+480) = 58 Hz. That should be ok. Subject to actual display requirements of course.
@Rudolf: I was considering a 'smartphone like' display for a product development. The lack of a metal frame on the front side should allow for easy bonding to a cover glass. Longevity of supply is of course the downside.
I don't have a datasheet indicating the complete timing requirements yet. Will report back.