Storing image data to 8-bit data width SDRAM using DCMI peripheral on STM32F446ZCH6

[DCosm.1]

I am currently working on an application involving streaming 480p/720p video from an OV5640 camera to an SD card (using SDIO) but I am afraid that the 128Kb of available SRAM are not enough.

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Given the situation, in order to increase the available RAM I am trying to interface​ an IS42S16800F-7BLI SDRAM chip with an STM32F446ZCH6 microcontroller on a dedicated PCB but I stumbled across the following problem:

​-Due to the amount of pins used, the STM32 can only communicate with the SDRAM using 8 bits of data

​-I am confused regarding where to connect the DQM pin of the SDRAM when working with 8-bit data width. From what I have read online, it has to be either tied to GND or to the FMC_NBL0 pin but according to STM32CubeIDE, the latter pin is currently used as DCMI_D2 for the DVP camera.

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Can someone clarify the process of properly interfacing the DQM pin in the 8 bits mode, or if the external SDRAM is even needed for this task in the first place?

[KDJEM.1]

Hi @DCosm.1​ and welcome to the Community :),

As IS42S16800F-7BLI and IS42S16800F-6BLI share the same datasheet, I assume that the article “How to set up the FMC peripheral to interface with the SDRAM IS42S16800F-6BLI from ISSI�? will be helpful for you to configure the SDRAM properly.

Kaouthar