STM32H757XIH6 - FMC interface with more than four chip selects

[ABhan.1]

Hi STM Team,

We are using STM32H757XIH6 microcontroller in our design for one of the project.

We are having the query regarding FMC port.

We are planning to use 8 bit data bus (FMC_D0-D7) of FMC port to drive multiple peripherals like LCD, Keypad, ADCs, IO cards etc.
We understand their are 4 Chip Selects NE1,NE2,NE3 and NE4.
We also intend to use GPIO pins to work as additional Chip Selects for all above peripherals.

Can we use the FMC port data lines (FMC_D0-D7) along with GPIOs as additional Chip Selects for above application?

Request you to please share the steps to configure FMC port for this application.

Could you please also confirm if we can use FMC port signals as GPIO signals?

Appreciate your support.

[mƎALLEm]

Hello,

To expend NE/Chip select better to use 3 to 8 line decoder like the 74xx138 or equivalent.

A, B and C inputs of that decoder are connected to the highest lines address of the FMC. So one SRAM bank will be divided to 8 regions equal of size of 8MByte.

G input of the 74xx138 will be connected to one of the NE of the FMC pins.

Example with FMC_NE0 and the different devices address (maximum 8 devices per FMC_NEx):

Hope that helps.