STM32F4xx and external sram memories.

[psilva]

Posted on March 19, 2013 at 11:34

Hi all,

I am new here and to stm products.

I read the datasheet for STM32F407, and a doubt born, the FSMC, seems to don't work in chips with 100 pins, because I saw that it does not have a several signs of this interface, so I ask, is this correct?

Thank you in advance.

Paulo

[John F.]

Posted on March 19, 2013 at 12:37

You could interface some memory if the microcontroller pins are multiplexed. Download and install ST's MicroXplorer for an easy way to get started with pin mapping. If you are not too bothered about speed, you could use serial RAM (Microchip) attached to the SPI bus.

[Tesla DeLorean]

Posted on March 19, 2013 at 15:17

The data manuals are pretty explicit about what functions escape on what pins. The FSMC uses a lot of pins. ST parts with more pins aren't instrinsically more expensive, although BGA parts tend to lead to much more expensive PCB designs.

I'd recommend you look at the fitter tools mention in the prior post, and also look at the schematics for some of ST's EVAL series boards which implement the features you want.

Consider how much memory you need, external memory is SLOW and is not cached. The STM32 may not be a good choice for high bandwidth external memory, Cortex-Mx parts are generally designed to work well with tightly coupled memory. There are STM32 parts with quite large internal flash and sram options, newer model support 2MB of flash, and external SDRAM interfaces.

[psilva]

Posted on March 20, 2013 at 10:59

Thank you all for the answers.

They helped me a lot.

Regards

Paulo