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-With this little programm you can write an EEPORM which is connected to a 
-Raspberry Pi with the GPIO pins.
+# 8bit breadboard computer
+
+This is a collection of little scripts to write the EEPROMs for a 8 bit 
+breadboard computer (by Ben Eater).
+The EEPROM is connected to the Raspberry Pi via the GPIO pins.
+
+## 7 hex display
+the computer has two 7 hex displays attach to it. With those display an 8bit 
+number can be displayed in hex format. The dispaly are controlled by two 
+EEPROMs. Setting the addresss lines to 0x1 on the EEPROM display a 1 on the 7 
+hex display. Setting the address lines to 0x2 displays a 2, ...
+
+## Control logic
+The control logic of the 8bit computer is implemented as two EEPROMs, which 
+computes a boolean function.
+In the script inst.py are the definitions of the hard-wired connections of the 
+EEPROM to the control signals. On top of that some micro instructions are 
+constructed.
+Furthermore the real instructions are implemented upon these micro instructions.
+
+Currently implemented instructions are:
+
+- LD{A,B}: Load the last four bits of the instruction into the A/B 
+  register
+- ADD/SUB_{A,B}: add/subtract the content of register B from the content of register A 
+  and save the results in register A or B respectively.
+- REG_{A,B}_OUT: display the conent of the register A/B on the 7 hex display
+- PC_LOAD: load the last four bits of the instruction into the programm counter 
+  register
+- HLT: halt the computer
+
+On the TODO list are conditional jump instructions and an instruction, so that 
+the 8bit breadbord computer an write to the EEPORM itself, and using it e.g. as 
+a stack.
+
+## example programms
+The following example programms are currently impletemened:
+
+- test programm: load the value 0x1 into register A and 0x2 into register B, 
+  adds the content and save it to register A.
+- fibonacci: loads the start values 0x1 and 0x1 into the register A and B and 
+  computes the fibonacci sequence.