STM32F777 Parallel Bus Interface

[RSHAR.2]

Hi,

I am working on STM32F777 MCU LQFP 176 Package.

I need to confirm if i can use FMC interface with my EtherCAT chip FIDO5200 that uses 16-bit data lines and 4-address lines.

Also I need to interface SRAM (parallel bus)that has 8-bit data and address lines.

Does STM32F777 can support both devices operating in parallel bus.If not, please suggect alternate MCU part.

Thanks,

Reshma

[waclawek.jan]

If FIDO5200 works exactly as SRAMs do (which it quite likely does), then you can use the FMC. You should confirm the timing of FMC matches (or can be adjusted) to requirements of FIDO.(it appears that yes, but the final decision is yours).

> Does STM32F777 can support both devices operating in parallel bus.

Yes, you simply use two different NEx pins to connect to chipselects of the two different memories (FIDO here plays role of a memory).

JW

[RSHAR.2]

Classification: Confidential
Hi,
Thanks for your quick response.
We understood from your response that data and address lines can be connected to FIDO and SRAM independently.
D0 to D15 data lines connected to FIDO chip and D16 to D31 connected to SRAM
Individual NE pins connected to FIDO and SRAM
For address lines, A0 to A3 lines connected to FIDO and A4 to A11 connected to SRAM for independent address configuration
Please clarify if I have understood correctly . If anything to add, please correct me.
Thanks & Regards,
Reshma

[waclawek.jan]

No. D0-D15 connected to FIDO and in parallel D0-D7 to SRAM.

Similarly, A0-A3 connected to FIDO and in parallel, A0-A7 connected to SRAM (are you sure this is a 256-byte SRAM?)

Also, /OE and /WE connected in parallel. The only thing which is connected individually are the NEx pins which connect to individual chipselects.

Review schematics of some Disco/EVAL boards (both 'F7xx and 'F4xx - the FMC is in principle the same on both), some of them do have two external memories connected to FMC.

JW

[RSHAR.2]

Understood the connections.

But still I am not sure if I want to read data from FIDO chip and write data into SRAM or vice versa

Can these both operations occur at same time?

Please clarify

[waclawek.jan]

> Can these both operations occur at same time?

At the same moment of time? No. Can they be performed one after the other? Yes.

JW