Rainbow-electronics T89C51AC2 Manuel d'utilisateur télécharger pdf (Page 44)

T89C51AC2

Rev. B – 19-Dec-01

10.5 Hardware Security

Byte

Table 14. Hardware Security byte

Default value after erasing chip: FFh

Note: Only the 4 MSB bits can be accessed by software.

Note: The 4 LSB bits can only be accessed by parallel mode.

76543210

X2B BLJB - - - LB2 LB1 LB0

Bit

Number

Bit

Mnemonic Description

7X2B

X2 Bit

Set this bit to start in standard mode

Clear this bit to start in X2 mode.

6BLJB

Boot Loader JumpBit

- 1: To start the user’s application on next RESET (@0000h) located in FM0,

- 0: To start the boot loader(@F800h) located in FM1.

5-3 -

Reserved

The value read from these bits are indeterminate.

2-0 LB2:0 Lock Bits

1 2 ... 39 40 41 42 43 44 45 46 47 48 49 ... 109 110

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Rainbow-electronics T89C51AC2 Manuel d'utilisateur Page 44