Hello everyone, I have used W78E516 MCU for designing, in the source code, some varibles had been defined as XDATA, but while the code running by a simulater the LCD using for display can not work normaly(blink and no letter can be seen), but if I download the HEX code into the MCU, W78E516 work fine, It made me puzzled. in the source code I had enable the xdata of the MCU,using code like below: <per> CHPENR=0x87; CHPENR=0x59; CHPCON=CHPCON | 0x10; CHPENR=0x00; </per> Does anyone who had met related problems and some advices or solution will be aprreciated.