AT89C51SND1_06 ATMEL [ATMEL Corporation], AT89C51SND1_06 Datasheet - Page 8
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AT89C51SND1_06
Manufacturer Part Number
AT89C51SND1_06
Description
USB Microcontrollers
Manufacturer
ATMEL [ATMEL Corporation]
Datasheet
1.AT89C51SND1_06.pdf
(33 pages)
Registers
Special Function
Register
Hardware Bytes
8
AT89C51SND1
Table 4. AUXR1 Register
AUXR1 (S:A2h) – Auxiliary Register 1
Reset Value = XXXX 00X0b
Note:
Table 5. HSB Byte – Hardware Security Byte
Reset Value = XXUU UXXX, UUUU UUUU after an hardware full chip erase.
Bit Number
Bit Number
7 - 6
X2B
5-4
2-0
7
5
4
3
2
1
0
7
7
6
3
-
1. ENBOOT bit is only available in AT89C51SND1 product.
ENBOOT
Mnemonic
Mnemonic
LB2:0
BLJB
X2B
BLJB
GF3
DPS
Bit
Bit
-
6
0
6
(3)
-
-
-
-
-
(1)
(2)
(3)
(1)
Description
Reserved
The value read from these bits are indeterminate. Do not set these bits.
Enable Boot Flash
Set this bit to map the boot Flash in the code space between at addresses F000h to
FFFFh.
Clear this bit to disable boot Flash.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
General Flag
This bit is a general-purpose user flag.
Always Zero
This bit is stuck to logic 0 to allow INC AUXR1 instruction without affecting GF3 flag.
Reserved for Data Pointer Extension.
Data Pointer Select Bit
Set to select second data pointer: DPTR1.
Clear to select first data pointer: DPTR0.
Description
X2 Bit
Program this bit to start in X2 mode.
Unprogram (erase) this bit to start in standard mode.
Boot Loader Jump Bit
Program this bit to execute the boot loader at address F000h on next reset.
Unprogram (erase) this bit to execute user’s application at address 0000h on next reset.
Reserved
The value read from these bits is always unprogrammed. Do not program these bits.
Reserved
The value read from this bit is always unprogrammed. Do not program this bit.
Hardware Lock Bits
Refer to for bits description.
ENBOOT
5
5
-
4
4
-
-
GF3
3
3
-
LB2
2
0
2
LB1
1
1
-
4254C–MP3–03/06
DPS
LB0
0
0