topic Re: Using external SDRAM memory in ColdFire/68K Microcontrollers and Processors

Using external SDRAM memory

KRichard — Sat, 26 May 2007 00:26:46 GMT

Hi, this is a newbie question about using external memory with ColdFire processors.

From the programmer's point of view (using CodeWarrior for ColdFire), is the external memory handling the same as if it were internal? I mean it is usable as if it were internal memory, without any hassle.

Or is it like it's an external "hard drive", so the programmer has to first fetch the data into the internal memory of the microprocessor, do the processing then maybe write the result back to the external storage?

Thanks in advance

Re: Using external SDRAM memory

mccPaul — Tue, 29 May 2007 18:52:52 GMT

Using external SDRAM is essentially the same as using the internal SRAM but you need to initialise it differently. All you need to do for SRAM is to change RAMBAR, but SDRAM requires more initialisation (dependent on your hardware and implementation).

There may also be some differences in bus width as the SRAM is on the internal 32 bit bus and your SDRAM may be on a 16-bit or DDR bus, but again there is no difference from the programmer's perspective once you have configured the SDRAM controller.

Cheers,

Paul.

Re: Using external SDRAM memory

KRichard — Fri, 01 Jun 2007 21:54:06 GMT

Thank you mccp, your reply was most helpful.

Have a nice day, Richard.