Rainbow Electronics AT89C5131 - Manual (Page 57)

57
AT89C5131
4136A–USB–03/03
• ALE high (or not connected)
– After Hardware Condition the FCON register is initialized with the value 00h
and the PC is initialized with F800h (FM1).
The Hardware condition makes the bootloader to be executed, whatever BLJB value is.
If no hardware condition is detected, the FCON register is initialized with the value F0h.
Check of the BLJB value.
• If bit BLJB = 1:
User application in FM0 will be started at 0000h (standard reset).
• If bit BLJB = 0:
Bootloader will be started at F800h in FM1.
Figure 24. Hardware Boot Process Algorithm
RESET
Hardware
Condition?
BLJB = = 0
?
bit ENBOOT in AUXR1 register
is initialized with BLJB.
Hardwa
re
So
ft
w
a
re
ENBOOT = 1
PC = F400h
ENBOOT = 1
PC = F400h
FCON = 00h
FCON = F0h
Bootloader
in FM1
ENBOOT = 0
PC = 0000h
Yes
Yes
No
No
Application
in FM0