BT815's Display Enable (DE) output is active positive.

I am trying to use a display with an ILI9806E driver which requires Display Enable to be active low.

How do I change the polarity of DE so that it is compatible with this display driver?

Thanks

Hi,

I was hoping to be able to draw filled polygons using an FT813 so that I can replace some large icon bitmaps with a small list of vertices, saving me a whole load of flash memory space.

I looked at application note AN334 https://brtchip.com/wp-content/uploads/Support/Documentation/Application_Notes/ICs/EVE/AN_334-FT801_Polygon_Application.pdf and I saw filled polygons.
On closer inspection, it seems that the polygon is split up into smaller sections so that they have vertical and horizontal edges for the scissor command to trim to.
This makes diagonals impractical however, as they would have to be cut up into squares whose sides match the width of the diagonal section. A long thin diagonal would require many cuts.
Concave polygons also need to be chopped up into straight edged convex pieces, and would need some thinking about..


Firstly, is filled concave polygons something that is likely to be supported in the future? Are the existing range of chips field upgradable, or would this feature require rolling out a new product?


Secondly, what would be the best way of getting around this?

1) I could draw over the unwanted part of the polygon with another polygon set to the background colour, but this wouldn't preserve non uniform backgrounds.

2) Perhaps I could draw to the stencil channel instead, but the stencil is 1bit and wouldn't have nice smooth edges when I fill, so far as I can tell from the docs, haven't tried it yet. I suppose I could then draw the outline with with a LINE_STIP to get the anti-aliased edges.

3) Or I could break up the icons into smaller components and composite them, making use of completely blank rectangular bitmaps that can be generated with the MEMFILL command and using the bitmap transform to rotate them to get the diagonals. Rotating bitmaps is a bit iffy, though. I did try animating a rotating circle and it did not look good. Its size and position kept shifting about.

4) Or I could give up and just use bitmaps, take the hit on space, hope deflate does a good job.

I think option (1) would suit my immediate needs, but I'd like to know if other folk have encountered this limitation, how they've gotten around it, and why that method, so I can make an informed decision before making a commitment.

Cheers,
 AT38

Hi,

I'm currently developing on an ME813A-WH50C display module.

I've had several days of trouble free operation.

Last night I power cycled the board as part of a debugging process.

Since then the display has not worked.

I am able to communicate over SPI and read out the chip ID register as 0x7C.

On examination of the display, I noticed that the back light was not on (no light bleeding out at the edges).

I have measured the voltage on the backlight pin and it is zero.

I've read out the values of REG_PWM_DUTY and REG_PWM_HZ and verified that their values are correct, 0x80 and 250 respectively.

I've tried shorting out the backlight pin to 3V3. This enables the backlight, but also sinks 30mA into the FT813.

There was no contact with the module between working and non working states.

Only the power button of the bench top supply was touched. ESD seems unlikely.

The PSU outputs 5v and drops to 3.3v on the MCU board via a linear regulator, and on the display module via a buck converter. Surge damage seems unlikely.

Wiring between the boards looks ok, and would foul SPI comms if not.

Can anyone tell me:
1) Why this has happened,
2) How do I fix it (preferably without shorting the pin to 3V3)
3) How do I prevent this from happening again?

Cheers


EDIT:

I've loaded a display list and forced the backlight on, but it looks like nothing is being displayed.
Possibly all out pins at zero. I'm going to check PCLK and DISP next.

EDIT2:

PCLK is outputting at 1.13MHz, should be 30MHz

DISP, VSYNC, HSYNC and DE are all Zero.