external ram

hpaskal · ‎2004-05-27

Posted on May 27, 2004 at 19:14

external ram

hpaskal · ‎2011-05-17

Posted on May 17, 2011 at 12:00

Hi !

i want to work with external ram with more than 256k.

1) is it possible to work with more than 8 pages ?

how can i do this ?

i only saw 8 signals fs0-fs7.

2) how can i work with extenal ram and not with main flash ?

all the docs and examples refers to the main flash and not to an external ram .

3)can anyone send me example of design with external ram ?

thanks

joseph2399 · ‎2011-05-17

Posted on May 17, 2011 at 12:00

1) Yes. You can use some I/O in output mode and these outputs can be used for address lines on your RAM in addition to the page register bits which you will need to bring out on unused I/O. You will need to use PSDsoft to program the CPLD portion of the device in this way. You will need to control the page register and I/O used as address lines in software.

2) You don't have to use all or any of the main flash. You specify what and how much of the main flash to use in PSDsoft.

3) Perhaps some other members of the forum have done this and can send you an example.

hpaskal · ‎2011-05-17

Posted on May 17, 2011 at 12:00

1)

[QUOTE]

''Yes, you can page XDATA. That is what you would do if you used the Main Flash for storing data.''

[/QUOTE]

Can u please explain how i can page XDATA?

should i use LX51 linker ?

is the uPsd know how to work with this linker ?

hpaskal · ‎2011-05-17

Posted on May 17, 2011 at 12:00

Thanks for the answer!

1) If I understand right, the paging is referring to code paging.

2) Is it possible to manage a paging also for Xdata ?

3) How?

4) In fact my project is a very big code and very big data variables.

so i understand that I need to implement paging for both code and

**data . Am I right ?

**Is it possible in uPsd device ?

**How it can be done ?

thanks

joseph2399 · ‎2011-05-17

Posted on May 17, 2011 at 12:00

1) You can page code or data.

2) Yes, you can page XDATA. That is what you would do if you used the Main Flash for storing data.

3) You can use the page register for paging of Main Flash, .

4) You mentioned you have big code and big data requirements. You could use the Main Flash for your big code and use the page register to page that code memory. You could attach external memory to the external bus on the 80-pin uPSD devices and with the help of the CPLD bring out some signals to page this memory.

joseph2399 · ‎2011-05-17

Posted on May 17, 2011 at 12:00

Take a look at this posting to see if it helps:

http://www.stmcu.com/forums-cat-1299-11.html

Be sure to see the attached files to the Moderator message.