Rainbow Electronics AT89C5131 - Manual (Page 60)

60
AT89C5131
4136A–USB–03/03
Hardware Byte
Default value after erasing chip: FFh
Notes: 1. Only the 4 MSB bits can be access by software.
2. The 4 LSB bits can only be access by parallel mode.
Table 47. Hardware Byte
7 6 5 4 3 2 1 0
X2B BLJB OSCON1 OSCON0 - LB2 LB1 LB0
Bit Number
Bit
Mnemonic Description
7 X2B
X2 Bit
Set this bit to start in standard mode
Clear this bit to start in X2 mode.
6 BLJB
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).
5-4 OSCON1-0
Oscillator Control Bits
These two bits are used to control the oscillator in order to reduce
consumption.
OSCON1
OSCON0 Description
1 1 oscillator is configured to run from 0 to 32 MHz
1 0 oscillator is configured to run from 0 to 16 MHz
0 1 oscillator is configured to run from 0 to 8 MHz
0 0 this configuration shouldn’t be set
3 -
Reserved
The value read from this bit is indeterminate.
2-0 LB2:0 Lock Bits