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STM32F429 LTDC 1-bit video

ken239955
Associate II
Posted on March 31, 2014 at 02:51

I am experimenting with the STM32F429 and wish to use the LCD-TFT controller (LTDC).

I am interested in generating monochrome 640x480 VGA video and hence only need 1-bit output rather than 8-bit RGB. Does anyone know if this is possible and if so, how to do it?

I have already done it with STM32F407 SPI DMA but now I want to take advantage of the STM32F429 LTDC hardware.
2 REPLIES 2
Posted on March 31, 2014 at 03:55

Yeah, I don't know, I'm pretty sure it's all byte orientated, and doesn't have a bit shifter.

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jj2
Associate II
Posted on March 31, 2014 at 05:51

Poster, ''generating mono - 640x480 (VGA) video and need only1-bit output rather than 8-bit RGB...''

Would it not ease your helper's efforts if you'd describe some of the how/why of your past success under past DMA?

When you state, ''8-bit RGB'' often that implies 8 bits per primary color - thus 24 bits total.  In your case - under your past DMA implementation - I'd suspect you grounded 23 of the RGB signal inputs - and output to the single remaining color bit.  (producing wondrous mono of that selected color - against all bits cleared low - when that single color bit is driven low.)  Often our group has used just such a technique - to quickly/easily perform initial tests/adjustments.  You can compare the 429's LCD outputs against that which you massaged via past DMA technique - seeking the best match for the LCD's required clocks and strobes.

In the event your display is ''really'' a TFT mono (Sharp at one time made a 640x480 TFT in glorious mono - a defrocked (i.e. Blk/wht distressed peacock image) shipped w/ that unit as ''truth in advertising'' logo...)  However - freed from the color management - it may be that you can input far beyond a single bit - with the added bits mapping to multiple, adjacent pixels.  (should the display be ''real'' color - which you seek to use only as mono - this method is not proper...)