http://www.8052.com/users/wek/disp.zip is the source modified for the free ASEM51 assembler.

In fact, it is pretty standard '51 assembler, except the macros; but there is only one macro used in a handful of places and as it expends only to two lines this expansion can be done easily by hand in 5 minutes.

The only other thing I had to change was the ascii 7Fh character in two strings, which ASEM did not like - I simply put it as a number.

Have fun!

JW

PS. It seems to me that the schematics are pretty incomplete or the software is related to some different version of the boards - I am missing the RTC and temperature sensor...