Datasheet

115
AT89C51IC2
4301D–8051–02/08
Boot Process
Figure 46. Bootloader process
RESET
Hardware
Condition?
BLJB!= 0
?
USER APPLICATION
Hardware
Software
FCON = 00h
FCON = F0h
FCON = 00h
?
Atmel BOOT LOADERUSER BOOT LOADER
yes = hardware boot
F800h
BLJB = 1
BSB = 00h
?
SBV = FCh
?
PC = 0000h
PC= [SBV]00h
conditions
BLJB = 0
If BLJB = 0 then ENBOOT bit (AUXR1) is set
else ENBOOT bit (AUXR1) is cleared
ENBOOT = 1
ENBOOT = 0
Yes (PSEN = 0, EA = 1, and ALE = 1 or not connected)