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8051 Architecture

1. Lets play with ITE IT8502E embedded controller firmware from Vostro V13 laptop It is available here

2. Find datasheet for this chip and open firmware with radare2:

r2 -a 8051 ite_it8502.rom

3. 8051 firmware have simple and flat structure, so it starts from the beginning:

[0x0000000]> pd 1
     ,=< 0x0000000      02002e     ljmp 0x2e

So go to the start function at 0x2e addr:

[0x0000000]> s 0x2e; pd 10
[0x0000002e]> pd 10
          0x0000002e      78fe             mov r0, 0xfe
          0x00000030      e4               clr a 
          0x00000031      f6               mov @r0, a
          0x00000032      d8fd             djnz r0, 0xfd
          0x00000034      7581d0           mov 0x81, #RAM_D0 
          0x00000037      901001           mov dptr, 0x1001
          0x0000003a      743f             mov a, 0x3f
          0x0000003c      f0               movx @dptr, a
          0x0000003d      02007d           ljmp 0x7d
          0x00000040      00               nop

… [some reversing] …

Lets see set_SMBus_frequency function:

embedded_controller.1369174001.txt.gz · Last modified: 2013/05/21 22:06 by xvilka