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Beginner

Date of registration: Apr 8th 2015

Posts: 1

1

Wednesday, April 8th 2015, 12:19pm

Is SDRAM neccessary?

Hi, I would like to use MCU from STM32F429I-DISCO to my home project. Example project for that testboard using SDRAM.

If I change LCD to another with lower resolutin, for example 320x240, is neccessery to use SDRAM? If I choose RGB565 color format, Video RAM will be 320*240*2 bytes. It's 150 kB of RAM and MCU has 256 kB of RAM. It should be OK.

Is this thinking right, or are there some problems to solve?

Thank you very much

rigomate

Beginner

Date of registration: Sep 5th 2014

Posts: 18

2

Friday, April 10th 2015, 2:04pm

The on board RAM should be sufficient to drive a 240x320 display.
But take note, that it does not have 256KB RAM.

It has 192 Kbyte Ram from the address: 0x2000000
And it has an additional 64 Kbyte CCMRAM, which is at address: 0x1000000


If you want to take use of the CCMRAM, you will have to modify your linker script.
Also take into account, that without double or tripple buffering, you'll have a flickering display.


You'll be able to use emwin's memdev feature, but it makes things a little more complicated than just having enough RAM for double buffering, and to let emwin handle things necessary for a smooth display.