Owner manual

57 Rev. F - 15 February, 2001
T89C51RD2
Boot process summary
The boot process is summarized on the following flowchart:
Figure 21. Boot process flowchart
CUSTOM BOOT
LOADER
- BSB: Boot Status Byte
- BLJB: Boot Loader Jump Bit (Hardware Bit set to
0 by default)
Jump to FC00h
DEFAULT BOOT
LOADER
Jump to 0000h
USER APPLICATION
Jump to XX00h
BLJB = 1
?
Software
Boot Vector ?
BSB ?
Hardware
Conditions
?
Yes (PSEN =0, EA =1, and ALE =1 or not connected)
Yes
BSB= 0
SBV= FCh
SBV FCh≠ XXh=
No
Hardware
Software
Reset Falling Edge
Jump to FC03h
No
BSB 00h≠