STM32H743IIT6 FMC NE producing multiple Clocks.

[john239955_st]

I have just changed from STM32F (works fine) to STM32H and have used MX to generate the Code for a SRAM 16 bits wide and 6 Address lines. The FMC outputs the NE clock but depending on the Data Bus Setting 8, 16, or 32, NE produces either 8, 4, or 2 Clocks respectively within the NE Clock, the Address also increments for each down clock within the NE. My reqiuirements are for a single NE Clock for a 16 Data Bus. It appears that the FMC always wants to clock a 64 bit word what ever the Data Bus size. Regards JohnW

[john239955_st]

Re:- Multiple Clocks ... In terms of Code, I have only added to the CubeMX Code as follow:-

In main.h added #define SRAM_DRIVER_ADDR 0x6000000 //NE1

in main.c while(1) {

// Delay;

*(___IO uint16_t *) (SRAM_DRIVER_ADDR + 0x0000) = 0x000; //

}

NSBank = FMC_NORSRAM_BANK1;

MemoryType = FMC_MEMORY_TYPE_SRAM;

MemoryDataWidth = FMC_NORSRAM_MEM_BUS_WIDTH_16;

.AddressSetupTime = 1;

.AddressHoldTime =1;

.DataSetupTime = 1;

.BusTurnAroundDuration = 0;

AccessMode = FMC_ACCESS_MODE_A

I have Silicon Revision Y

Any help would be appreciated ... K. Regards John W

[waclawek.jan]

From RM0433, FMC chapter, Supported memories and transactions

General transaction rules:

The memory region MPU attribute must be configured as “Device�? or “strongly-ordered�?

in order to prevent issues on devices that do not have the byte select feature. As an

example, if byte accesses are performed to 16-bit memories with the MPU attribute set

to “Normal memory�?, the AXI transaction size is 64 bits and the FMC splits the

transaction into four consecutive accesses while only one access is expected instead

of four.

I don't use 'H7.

JW

[john239955_st]

Thanks Jan ... That explains why I have 4 Write clocks within the NE1 ... I was at the point of going back to the STM32F427.

I may need to check out the attribute. Do you know if it changed in the Compiler/MXCube.

Thanks for the information KR ... JAW

[Amilton Rogério da Silva]

Hi john239955_st,

Have you solved the multiple write clocks problem? I've got the same issue with NWE (PD5) signal and dont't know how to configure to send only one.

[john239955_st]

Hi Amilton ... Yes had local FAE give some help.

The Memory has to be put into a Region this can be done from CubeMX, I made sure CubeMX was updated.

Only had this working yesterday so have not fully checked out

KR John W

[Trevor Jones]

Yep it fixed my issue, thanks for that...