AT89C51RB2-SLRUL Atmel, AT89C51RB2-SLRUL Datasheet - Page 93
![MCU 8051 16K FLASH 3V 44-PLCC](/photos/6/70/67043/453-44-plcc_sml.jpg)
AT89C51RB2-SLRUL
Manufacturer Part Number
AT89C51RB2-SLRUL
Description
MCU 8051 16K FLASH 3V 44-PLCC
Manufacturer
Atmel
Series
89Cr
Datasheet
1.AT89C51RB2-RLTIL.pdf
(127 pages)
Specifications of AT89C51RB2-SLRUL
Core Processor
8051
Core Size
8-Bit
Speed
40MHz
Connectivity
SPI, UART/USART
Peripherals
POR, PWM, WDT
Number Of I /o
32
Program Memory Size
16KB (16K x 8)
Program Memory Type
FLASH
Ram Size
1.25K x 8
Voltage - Supply (vcc/vdd)
2.7 V ~ 3.6 V
Oscillator Type
External
Operating Temperature
-40°C ~ 85°C
Package / Case
44-PLCC
For Use With
AT89STK-11 - KIT STARTER FOR AT89C51RX2
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Eeprom Size
-
Data Converters
-
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
AT89C51RB2-SLRUL
Manufacturer:
Atmel
Quantity:
500
Bootloader Functionality
Introduction
Figure 38. Hardware conditions typical sequence during power-on.
4180E–8051–10/06
The bootloader can be activated by two means: Hardware conditions or regular boot
process.
The Hardware conditions (EA = 1, PSEN = 0) during the Reset# falling edge force the
on-chip bootloader execution. This allows an application to be built that will normally
execute the end user’s code but can be manually forced into default ISP operation.
As PSEN is an output port in normal operating mode (running user application or boor-
loader code) after reset, it is recommended to release PSEN after falling edge of reset
signal. The hardware conditions are sampled at reset signal falling edge, thus they can
be released at any time when reset input is low.
To ensure correct microcontroller startup, the PSEN pin should not be tied to ground
during power-on (See Figure 38).
The on-chip bootloader boot process is shown in Figure 39.
Hardware Conditions
BLJB
SBV
VCC
PSEN
RST
Purpose
The Hardware Conditions force the bootloader execution whatever BLJB, BSB
and SBV values.
The Boot Loader Jump Bit forces the application execution.
BLJB = 0 => Boot loader execution.
BLJB = 1 => Application execution.
The BLJB is a fuse bit in the Hardware Byte.
That can be modified by hardware (programmer) or by software (API).
Note:
The BLJB test is perform by hardware to prevent any program execution.
The Software Boot Vector contains the high address of custumer bootloader
stored in the application.
SBV = FCh (default value) if no custumer bootloader in user Flash.
Note:
The costumer bootloader is called by JMP [SBV]00h instruction.
AT89C51RB2/RC2
93