i am now using LCD HD44780 2 line x 14 char to interface to my system board with 20 sensors input. I use 8255 to interface to all the sensor input and use 8051's ports to interface with LCD. Now i face a problem of displaying message from only the activated sensor in ascend order (every sensor is identified by an ID). If certain sensors reset, then the whole arrangement must be reordered so that the LCD only display the activated one.

my sensor record format : x00y yyyy 8 bits)

x - active/inactive
yyyyy - sensor id (#00001b - #10100b)

i declared 20 address at offchip RAM to hold the 20 sensors records. i always need to rearrange the record so that the inactive one at the back of the storage and active one at the front. when i need to display the message to LCD, then i will check the record start from the front and stop when i reach to the first inactive sensor record. That's why I must have a subroutine to do the rearrangement first.

do anyone know to do that rearrangement by using 8051 assembly lang?

Best Regards,
Jeffrey Ng