AT89C51RB2 Atmel Corporation, AT89C51RB2 Datasheet - Page 94

• Manufacturer Part Number: AT89C51RB2
• Manufacturer: Atmel Corporation

Specifications of AT89C51RB2

• Flash (kbytes): 16 Kbytes
• Max. Operating Frequency: 60 MHz
• Cpu: 8051-12C
• Max I/o Pins: 32
• Spi: 1
• Uart: 1
• Sram (kbytes): 1.25
• Self Program Memory: API
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Isp: UART
• Watchdog: Yes

Boot Process
Figure 39. Bootloader process
94
AT89C51RB2/RC2
USER APPLICATION
PC = 0000h
ENBOOT = 0
BLJB = 1
USER BOOT LOADER
PC= [SBV]00h
BSB = 00h
SBV = FCh
FCON = 00h
Condition?
Hardware
BLJB!= 0
RESET
?
?
?
?
F800h
If BLJB = 0 then ENBOOT bit (AUXR1) is set
BLJB = 0
ENBOOT = 1
FCON = F0h
Yes (PSEN = 0, EA = 1, and ALE = 1 or not connected)
FCON = 00h
yes = hardware boot
else ENBOOT bit (AUXR1) is cleared
Atmel BOOT LOADER
conditions
4180E–8051–10/06