Thomas, what I mean is pointer to function.
I am using function pointer like below.
The programming code are:
...
...
void (*key_encoder)(void);
void k_idle(void),k_decode(void);

init_key_encoder();
while(1)
{
(*key_encoder)();
}

void init_key_encoder(void)
{
key_encoder = k_idle;
}
void k_idle(void)
{
key_encoder = k_decode;
}
void k_decode(void)
{
key_encoder = k_idle;
}
...
...

-How to declare the pointer variable used on xdata in this case?

Sakri