Hi Aad,

the error at "org 0Bh" can have some reasons:
1. there was already code written at 0Bh

2. some simple assemblers accept no org statement with values below the current address.


Also I think, its not easy to start with an 8051 and already immense hardware attach on it.
If I would start now with the 8051, I would build a board with nothing more than:
- the AT89S8252,
- P1.5 - P1.7, Reset connected to the printer port for download,
- 10µF from Reset to VCC
- crystal 11.0592MHz + 2 * 33pF
- 8 switches against GND on P2
- 8 LEDs + 8 * 1kOhm against VCC on P0


Peter