Memory in Framebuffer with 18-bit per Pixel

[lpcware]

Content originally posted in LPCWare by Martin84 on Wed Jul 31 00:40:38 MST 2013
Hi,

I'm using an 18-bit TFT and I wanna calculate the memory that one frame will need. The resolution is 640x480, so I calculate as follows: 640*480*18bit = 5529600 bits -> 5529600 / 8 = 691200 Bytes = 691kB.

Is the calculation with 18-bit correct or do i have to use 32-bit?

Regards,

Martin

[lpcware]

Content originally posted in LPCWare by Martin84 on Wed Jul 31 02:58:48 MST 2013
Ok thank you :-)

Regards,

Martin

[lpcware]

Content originally posted in LPCWare by Wouter on Wed Jul 31 01:01:37 MST 2013
Hi Martin,

You would need to use 32bpp framebuffer for 18-bit RGB.
I'd recommend to switch to 5:6:5 (16-bit) mode. This will save memory, but more importantly reduce the bus bandwidth used by the LCD controller.
You can wire your display for 18-bit mode, and always decide in SW to use 16-bit or 18-bit mode.

Regards,
Wouter