Rainbow-electronics T89C5115 Manuel d'utilisateur télécharger pdf (Page 39)

T89C5115

4128A–8051–04/02

Boot Process

Software Boot Process

Example

Many algorithms can be used for the software boot process. Before describing them,

The description of the different flags and bytes is given below:

Boot Loader Jump Bit (BLJB):

- This bit indicates if on RESET the user wants to jump to this application at address

@0000h on FM0 or execute the boot loader at address @F800h on FM1.

- BLJB = 0 on parts delivered with bootloader programmed.

- To read or modify this bit, the APIs are used.

Boot Vector Address (SBV):

- This byte contains the MSB of the user boot loader address in FM0.

- The default value of SBV is FFh (no user boot loader in FM0).

- To read or modify this byte, the APIs are used.

Extra Byte (EB) & Boot Status Byte (BSB):

- These bytes are reserved for customer use.

- To read or modify these bytes, the APIs are used.

Figure 17. Hardware Boot Process Algorithm

RESET

BLJB == 0

Hardware

Software

Boot Loader

in FM1

Application

in FM0

bit ENBOOT in AUXR1 register

is initialized with BLJB.

ENBOOT = 0

PC = 0000h

ENBOOT = 1

PC = F800h

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Rainbow-electronics T89C5115 Manuel d'utilisateur Page 39