Printed in 1975, the 24 pages of ENGINEERING NOTE 100 contain the source code for the MIKBUG
monitor which was in the boot ROM of most MC6800 systems.
Even computers that used other monitors used MIKBUG entry
points for I/O subroutines.
Here is the Manual for the M6800 8K Cassette Basic.
It was a bit slow because it used
BCD arithmetic but it packed a lot of features in 8K.