at89c51re2-slsem ATMEL Corporation, at89c51re2-slsem Datasheet - Page 34

• Manufacturer Part Number: at89c51re2-slsem
• Description: At89c51re2 8-bit Flash Microcontroller
• Manufacturer: ATMEL Corporation

Fuse Configuration Byte (FCB)
34
AT89C51RE2
The Fuse configuration byte is a part of FM0.
The 8 bits read/written by software (from FM0 or RM0) and written by hardware in paral-
lel mode.
Table 19. Fuse Configuration Byte (FCB)
Number
Bit
6-3
2-0
X2
7
7
Mnemonic
BRV2-0-
Bit
X2
-
6
-
Description
X2 Mode
Programmed (‘0’ value) to force X2 mode (6 clocks per instruction) after reset
Unprogrammed (‘1’ value) to force X1 mode, Standard Mode, after reset (Default)
Unused
Boot Reset Vector
These bits allow to configure the reset vector of the product according to the
following values:
1 1 1 : Reset at address 0x0000 of FM0 with Bank0 mapped
1 1 0 : Reset at address 0xFFFC of Bank 0
1 0 1 : Reset at address 0xFFFC of Bank 1
1 0 0 : Reset at address 0xFFFC of Bank 2
0 1 1 : Reset at address 0x0000 of RM0 (Internal ROM bootloader execution)
0 1 0 : Reserved for further extension but same as 1 1 1
0 0 1 : Reserved for further extension but same as 1 1 1
0 0 0 : Reserved for further extension but same as 1 1 1
5
-
4
-
3
-
BRV2
2
BRV1
1
7663B–8051–03/07
BRV0
0