Hi Guys:
Please bear with my dumb questions. I am trying to understand how the
FALSH and RAM memories are used in a DSP chip. My understanding is
that the FLASH is like the hard drive while the RAM in a DSP is same
as the RAM in a computer. With 56F8013, we have 16kB Flash and 4kB
RAM.
Is it correct when a DSP starts running, the program stored in the
Flash is dumped into the RAM first?
If so, why do we have larger Flash than RAM since the largest program
could be used is the size of the RAM rather than the Flash?
Is it possible that only portion of a program is moved to the RAM and
if it is, how can we manage it when we do the coding?
Thanks for the help.
Haoye Shen
Flash and RAM memories
Started by ●December 1, 2005
Reply by ●December 2, 20052005-12-02
Hi Haoye,
Flash is not as quick as the RAM and so it's used to store the overall application while RAM is used to run the current one.
It's like a paging solution, I think.
I hope you agree.
Ciao,
Domenico
Reply by ●December 2, 20052005-12-02
You are using the embedded controller ( a device
combines CPU, memory, peripherals onto one single
silicon), which flash and RAM have the same access
speed. So when device starts running, program runs
directly from flash. RAM normally uses for storing
variables and other temporary values.
8013 flash can be used for stroing both program and
constant data. Its RAM can be used to store varilables
as well as constant data too. This RAM also can be
accessed from both program buses and data buses. Why?
Because if you want to runtime update flash contents,
the program must run from other memory rather than
flash itself.
When you do the coding, the link-command flie (
generated by Codewarrior but can be modified by user)
will manage your code allocation.
Charlie
--- haoyeshen <haoyeshen@haoy...> wrote:
> Hi Guys: > Please bear with my dumb questions. I am trying to
> understand how the
> FALSH and RAM memories are used in a DSP chip. My
> understanding is
> that the FLASH is like the hard drive while the RAM
> in a DSP is same
> as the RAM in a computer. With 56F8013, we have 16kB
> Flash and 4kB
> RAM.
>
> Is it correct when a DSP starts running, the program
> stored in the
> Flash is dumped into the RAM first?
>
> If so, why do we have larger Flash than RAM since
> the largest program
> could be used is the size of the RAM rather than the
> Flash?
>
> Is it possible that only portion of a program is
> moved to the RAM and
> if it is, how can we manage it when we do the
> coding? > Thanks for the help. >
> Haoye Shen
__________________________________
Start your day with Yahoo! - Make it your home page!
http://www.yahoo.com/r/hs
combines CPU, memory, peripherals onto one single
silicon), which flash and RAM have the same access
speed. So when device starts running, program runs
directly from flash. RAM normally uses for storing
variables and other temporary values.
8013 flash can be used for stroing both program and
constant data. Its RAM can be used to store varilables
as well as constant data too. This RAM also can be
accessed from both program buses and data buses. Why?
Because if you want to runtime update flash contents,
the program must run from other memory rather than
flash itself.
When you do the coding, the link-command flie (
generated by Codewarrior but can be modified by user)
will manage your code allocation.
Charlie
--- haoyeshen <haoyeshen@haoy...> wrote:
> Hi Guys: > Please bear with my dumb questions. I am trying to
> understand how the
> FALSH and RAM memories are used in a DSP chip. My
> understanding is
> that the FLASH is like the hard drive while the RAM
> in a DSP is same
> as the RAM in a computer. With 56F8013, we have 16kB
> Flash and 4kB
> RAM.
>
> Is it correct when a DSP starts running, the program
> stored in the
> Flash is dumped into the RAM first?
>
> If so, why do we have larger Flash than RAM since
> the largest program
> could be used is the size of the RAM rather than the
> Flash?
>
> Is it possible that only portion of a program is
> moved to the RAM and
> if it is, how can we manage it when we do the
> coding? > Thanks for the help. >
> Haoye Shen
__________________________________
Start your day with Yahoo! - Make it your home page!
http://www.yahoo.com/r/hs
