AT89LP51ID2 Atmel Corporation, AT89LP51ID2 Datasheet - Page 203

• Manufacturer Part Number: AT89LP51ID2
• Manufacturer: Atmel Corporation

Specifications of AT89LP51ID2

• Flash (kbytes): 64 Kbytes
• Max. Operating Frequency: 20 MHz
• Cpu: 8051-1C
• Max I/o Pins: 42
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Adc Channels: 7
• Adc Resolution (bits): 10
• Adc Speed (ksps): 153.8
• Sram (kbytes): 2.25
• Eeprom (bytes): 4096
• Self Program Memory: API
• Operating Voltage (vcc): 2.4 to 5.5
• Timers: 4
• Isp: SPI/OCD/UART
• Watchdog: Yes

24.5.2
24.5.2.1
3714A–MICRO–7/11
Bootloader Resources
Hardware Register
The on-chip bootloader boot process is shown
Bootloader Process Description
Several on-chip resources are provided for use by the bootloader.
The hardware register of the AT89LP51RD2/ED2/ID2 is called the Hardware Byte or Hardware
Security Byte (HSB). It is a shadow of selected resources from the User Fuses and Hardware
Security Bits.
Table 24-12. Hardware Security Byte (HSB)
Hardware Condition
BLJB
SBV
Number
Bit
2-0
7
6
5
4
3
X2
7
Mnemonic
XRAM
LB2-0
BLJB
OSC
Bit
BLJB
X2
-
6
Description
X2 Mode
Programmed (‘0’ value) to force X2 mode after reset.
Unprogrammed (‘1’ Value) to force X1 mode after reset (Default).
Boot Loader Jump Bit
Unprogrammed (‘1’ value) to start the user’s application on next reset at address 0000h.
Programmed (‘0’ value) to start the boot loader at address F800h on next reset (Default).
Oscillator Bit
Programmed to allow oscillator B at startup
Unprogrammed this bit to allow oscillator A at startup (Default).
Reserved
XRAM config bit (only programmable by programmer tools)
Programmed to inhibit XRAM.
Unprogrammed, this bit to valid XRAM (Default).
User Memory Lock Bits (only programmable by programmer tools)
See
Table 24-13
AT89LP51RD2/ED2/ID2 Preliminary
5
-
Purpose
The Hardware Condition forces the bootloader execution whatever the
BLJB, BSB and SBV values.
The Boot Loader Jump Bit forces the application execution.
BLJB = 0 => Bootloader execution
BLJB = 1 => Application execution
The BLJB is a User configuration fuse. It can be modified by hardware
(programmer) or by software (API). Note: The BLJB test is performed by
hardware to prevent any program execution.
The Software Boot Vector contains the high address of customer
bootloader stored in the application.
SBV = FCh (default value) if no customer bootloader in user Flash.
Note: The customer bootloader is called by JMP [SBV]00h instruction.
4
-
Figure 24-9 on page 204
XRAM
3
LB2
2
and described in
LB1
1
LB0
Table
0
203
.