#10 Error in especifying a address

[Anonymous]

Hi,

I´m working in a 8051 microcontroler and I have a device (a LCD)
placed in a specific address. I need to determine it´s address in
the program. I tryed to do that

sfr at 0x4000 LCD;

But it seens not to work. Running the S51 simulator, I realised that
every byte that I tryed to write to the LCD was writen to the
address 0x00 of the internal memory.

So I tryed this:

#define LCD (*(char*) 0x4000)

It works fine, but I get the message:

warning *** LITERAL value being cast to '_generic' pointer

How can I avoid this? There´s a better way to do that?

Thanks.

[Jesus Calvino-Fraga]

Logged In: YES
user_id=603650

You could try something like this:

xdata char at 0x4000 LCD;

void main (void)
{
int j;
LCD=0x55;
for(j=0; j<100; j++);
LCD=0xaa;
}

[a_wombat]

Logged In: YES
user_id=1329887

SFR's refer to a specific memory space in 8051 hardware. It
strikes me that your 0x4000 address must be in the external RAM
space of the 8051.

try the xdata directive instead.
ie:
xdata at 0x4000 LCD;

[a_wombat]

Logged In: YES
user_id=1329887

SFR's refer to a specific memory space in 8051 hardware. It
strikes me that your 0x4000 address must be in the external RAM
space of the 8051.

try the xdata directive instead.
ie:
xdata at 0x4000 LCD;