AT89C5131-PLTIL ATMEL Corporation, AT89C5131-PLTIL Datasheet - Page 45

• Manufacturer Part Number: AT89C5131-PLTIL
• Description: 8-bit Flash Microcontroller with Full Speed USB Device
• Manufacturer: ATMEL Corporation

Hardware Security Byte
4136B–USB–09/03
Table 44. Hardware Security Byte
Default value after erasing chip: FFh
Notes:
Bit Number
X2B
5-4
2-0
7
7
6
3
1. Only the 4 MSB bits can be access by software.
2. The 4 LSB bits can only be access by parallel mode.
Mnemonic
OSCON1-0
BLJB
LB2:0
BLJB
6
X2B
Bit
-
OSCON1
Description
X2 Bit
Set this bit to start in standard mode
Clear this bit to start in X2 mode.
Bootloader Jump Bit
Set this bit to start the user’s application on next reset at address 0000h.
Cleared this bit to start the bootloader at address F400h (default).
Oscillator Control Bits
These two bits are used to control the oscillator in order to reduce
consumption.
OSCON1 OSCON0 Description
Reserved
The value read from this bit is indeterminate.
Lock Bits
1
1
0
0
5
1
0
1
0
OSCON0
4
oscillator is configured to run from 0 to 32 MHz
oscillator is configured to run from 0 to 16 MHz
oscillator is configured to run from 0 to 8 MHz
this configuration shouldn’t be set
3
-
LB2
2
AT89C5131
LB1
1
LB0
0
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