Hello, I have an application where I will have a LCD display with several menus and so I will want to have lots of const arrays of text stored in flash. Does anyone know if you can read from internal flash memory, (i.e. access constants stored in flash) with a Atmel AT91SAM7S64? Someone was telling me there is no way to read from internal flash while executing code from the flash on this part. Is that correct? Thanks, Andy
Read from flash with AT91SAM7S64
Started by ●September 16, 2005
Reply by ●September 17, 20052005-09-17
On Fri, 16 Sep 2005 15:15:00 -0500, "Andy" <ydna1000@hotmail.com> wrote:>Hello, > >I have an application where I will have a LCD display with several menus and >so I will want to have lots of const arrays of text stored in flash. >Does anyone know if you can read from internal flash memory, (i.e. access >constants stored in flash) with a Atmel AT91SAM7S64? >Someone was telling me there is no way to read from internal flash while >executing code from the flash on this part. Is that correct? >You can definately read from the flash while executing from it, whether you can write to the falsh while executing from it. is a different story. Acccesing data stored in flash is no different than accesing it from RAM. Regards Anton Erasmus
Reply by ●September 20, 20052005-09-20
"Anton Erasmus" <nobody@spam.prevent.net> wrote in message news:1126941332.79656140a54495dba2d3d921147248b7@teranews...> On Fri, 16 Sep 2005 15:15:00 -0500, "Andy" <ydna1000@hotmail.com> > wrote: > >>Hello, >> >>I have an application where I will have a LCD display with several menus >>and >>so I will want to have lots of const arrays of text stored in flash. >>Does anyone know if you can read from internal flash memory, (i.e. access >>constants stored in flash) with a Atmel AT91SAM7S64? >>Someone was telling me there is no way to read from internal flash while >>executing code from the flash on this part. Is that correct? >> > > You can definately read from the flash while executing from it, > whether you can write to the falsh while executing from it. is a > different story. Acccesing data stored in flash is no different than > accesing it from RAM. > > Regards > Anton Erasmus >Thanks for the response. I was hopeing it would not have to use a mechanism like the old Microchip parts where to read const from flash you had to do a return with literal. This would be very inefficient with 32 bit wide instructions.
Reply by ●September 21, 20052005-09-21
Andy wrote:> "Anton Erasmus" <nobody@spam.prevent.net> wrote in message > news:1126941332.79656140a54495dba2d3d921147248b7@teranews... > >>On Fri, 16 Sep 2005 15:15:00 -0500, "Andy" <ydna1000@hotmail.com> >>wrote: >> >> >>>Hello, >>> >>>I have an application where I will have a LCD display with several menus >>>and >>>so I will want to have lots of const arrays of text stored in flash. >>>Does anyone know if you can read from internal flash memory, (i.e. access >>>constants stored in flash) with a Atmel AT91SAM7S64? >>>Someone was telling me there is no way to read from internal flash while >>>executing code from the flash on this part. Is that correct? >>> >> >>You can definately read from the flash while executing from it, >>whether you can write to the falsh while executing from it. is a >>different story. Acccesing data stored in flash is no different than >>accesing it from RAM. >> >>Regards >> Anton Erasmus >> > > > Thanks for the response. I was hopeing it would not have to use a mechanism > like the old Microchip parts where to read const from flash you had to do a > return with literal. This would be very inefficient with 32 bit wide > instructions.There is a basic difference with old PICs and ARMs: - the old PICs have totally separate instruction / data memories - the ARMs use common instruction / data memory space. -- Tauno Voipio tauno voipio (at) iki fi
Reply by ●September 21, 20052005-09-21
"Tauno Voipio" <tauno.voipio@iki.fi.NOSPAM.invalid> wrote in message news:S37Ye.46$635.8@read3.inet.fi...> Andy wrote: >> "Anton Erasmus" <nobody@spam.prevent.net> wrote in message >> news:1126941332.79656140a54495dba2d3d921147248b7@teranews... >> >>>On Fri, 16 Sep 2005 15:15:00 -0500, "Andy" <ydna1000@hotmail.com> >>>wrote: >>> >>> >>>>Hello, >>>> >>>>I have an application where I will have a LCD display with several menus >>>>and >>>>so I will want to have lots of const arrays of text stored in flash. >>>>Does anyone know if you can read from internal flash memory, (i.e. >>>>access >>>>constants stored in flash) with a Atmel AT91SAM7S64? >>>>Someone was telling me there is no way to read from internal flash while >>>>executing code from the flash on this part. Is that correct? >>>> >>> >>>You can definately read from the flash while executing from it, >>>whether you can write to the falsh while executing from it. is a >>>different story. Acccesing data stored in flash is no different than >>>accesing it from RAM. >>> >>>Regards >>> Anton Erasmus >>> >> >> >> Thanks for the response. I was hopeing it would not have to use a >> mechanism like the old Microchip parts where to read const from flash you >> had to do a return with literal. This would be very inefficient with 32 >> bit wide instructions. > > There is a basic difference with old PICs and ARMs: > > - the old PICs have totally separate instruction / data memories > - the ARMs use common instruction / data memory space. > > -- > > Tauno Voipio > tauno voipio (at) iki fi > >Wow I thought for sure all ARMs were arm Harvard architecture. Looking around now I see ARM7 is Von Neuman. Sorry I did not do my home work before posting.
