The datasheet for the encoder says it needs to be modulated with 4 words of data. I think it also must be modulated with a data address.

Is your micro-controller doing this?

 

how to check this ?

 

I have no idea what your circuit is supposed to do.

 

i got it ........the data can only transmit 4 bits once at a time so that all data's are splitted onto 4 bits

 

SEND_DATA:
JNB ACC.0,FG1
SETB DB0
AJMP FG2
FG1: CLR DB0
FG2: JNB ACC.1,FG3
SETB DB1
AJMP FG4
FG3: CLR DB1
FG4: JNB ACC.2,FG5
SETB DB2
AJMP FG6
FG5: CLR DB2
FG6: JNB ACC.3,FG7
SETB DB3
AJMP FG8
FG7: CLR DB3
FG8: RET
the micro-controller will send 4 bit to the encoder DB0,DB1,DB2,DB3