Again, I haven't had time to study this too closely, but I did quickly review Keil application note 161. On page 5 they have a diagram that suggests the LCD should be read while EN is high and that data should be written while EN is low. But your code would appear to be reading the LCD while EN is low.

Try modifying the ReadInstrReg code to:

DISPDATA=0xFF;// set port for all inputs
REGSEL=0;// Select inst. register
RDWR=  1; // read mode
ENABLE=1;// enable LCD
_nop_();
Instr=DISPDATA;//read in the data
_nop_();
ENABLE=0;//disable LCD

All I did was move the Instr=DISPDATA instruction into the middle of the nops rather than after ENABLE=0. That way you will be reading the value while EN is high, as the application note suggests.

Good luck.

Craig Steiner