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Rainbow Electronics T89C51RD2 User Manual

Page 57

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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