9S12XS/XE Reading FAR Memory - Addressing issue in DataFlash

[Heppell]

Hi, I've written a dataflash "driver" which writes data into the DF, it also needs to read the dataflash and compare with the original data to be written in order to complete.

So the dataflash is being written, thats working fine, but I cannot get my read and verify code to work, I think it is an error in the way I am writing my code below, Could someone Help?


/* Verify Write Operation */
df_ptr = (UINT8 @far *)(0x100000u | dfInfo.saved.dfAddress);

while ((*df_ptr == *dfInfo.saved.ramAddress) && (dfInfo.saved.totalCount > 0u))
{
   df_ptr++;
   dfInfo.saved.ramAddress++;
   dfInfo.saved.totalCount--;
}
if (dfInfo.saved.totalCount > 0u) { ..error.. }

Thanks!
-Rene

[Heppell]

UINT8 @far * df_ptr;

struct s_dfInfo
{
   CALLBACK callbackFn;
   UINT16 callbackParam;
   BOOL lastWriteStatus;
   BOOL bWriteDisable;
   UINT8 state;
   struct s_dfAddressInfo current;
   struct s_dfAddressInfo saved;
};

struct s_dfAddressInfo
{
   UINT16 totalCount;
   UINT16 dfAddress;
   UINT8* ramAddress;
};

struct s_dfInfo dfInfo;

[Pedro_]

After a quick experiment, something like this will work

static @far @eeprom word wBaseAddr @0x100000;
wValueInDFlash = *(&wBaseAddr + wOffset);

I hope it helps.

[Heppell]

I've changed the code as per your advice, and I still can't get this to work properly. I'm also not sure about the @eeprom flag, which I tried with or without, but with no luck.


   UINT8 @far * df_ptr;
   static @far UINT16 wBaseAddr @0x100000;

         df_ptr = (&wBaseAddr + dfInfo.saved.dfAddress);

         while ((*df_ptr == *dfInfo.saved.ramAddress) && (dfInfo.saved.totalCount > 0u))
         { ... is not satisfied, but should be ... }

[Pedro_]

Not having used the @eeprom modified, the compiler will not resolve the pointer assignement as you have coded.

@far data and @far @eeprom (dflash or eee) correspond to different sections of the memory map.

try something like this.

static @far @eeprom UINT8 wBaseAddr @0x100000

while(dfInfo.saved.totalCount > 0)
{
  if ( *(&wBaseAddr+Offset) != *(dfInfo.saved.ramAddress+Offset) )
  {
    /* doesnt match */
   break;
  }

  Offset++;
  dfInfo.saved.totalCount--;
}

The controller is able to access 16bit data, so you should probably use UINT16 for both the wBaseAddr and the ramAddress rather than UINT8

[Heppell]

Thanks for helping out Pedro!

I'm still having issues getting these two statements to match, heres my latest code attempt:

static @far @eeprom UINT16 wBaseAddr @0x100000;
...
if ( (UINT8)(*(&wBaseAddr+dfInfo.saved.dfAddress+Offset)) != (UINT8)(*(dfInfo.saved.ramAddress+Offset)) )
{ ...

Where:
dfInfo.saved.dfAddress = 0
dfInfo.saved.ramAddress = 0xffff4
Offset = 0

sizeof(dfInfo.saved.ramAddress) = 8 <-- has to be kept at UINT8
sizeof(Offset) = 16
sizeof(dfInfo.saved.dfAddress) = 16

Viewing memory at 0x100000 shows 48 65 6c 6c 6f...
Viewing memort at 0xffff4 shows 48 65 6c 6c 6f...

[Heppell]

Changing the line
static @far @eeprom UINT16 wBaseAddr @0x100000;
to
static @far @eeprom UINT8 wBaseAddr @0x100000;

Now fixes the code! Thanks alot for the help Pedro!

[Pedro_]

The problem might be related to the way you have declared the pointer

try

@far @eeprom char *df_ptr

what type is dfInfo.saved.ramAddress ?

Message Edited by Pedro_ on 2009-01-20 12:09 PM