T89C51RD2-3CSCL ATMEL [ATMEL Corporation], T89C51RD2-3CSCL Datasheet - Page 61
T89C51RD2-3CSCL
Manufacturer Part Number
T89C51RD2-3CSCL
Description
0 to 40 MHz Flash Programmable 8-bit Microcontroller
Manufacturer
ATMEL [ATMEL Corporation]
Datasheet
1.T89C51RD2-3CSCL.pdf
(104 pages)
- Current page: 61 of 104
- Download datasheet (2Mb)
Bootloader Functionality
Introduction
4243G–8051–05/03
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.
The on-chip bootloader boot process is shown in Figure 24.
Hardware Conditions
BLJB
SBV
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 custumer bootloader is called by LJMP [SBV]00h instruction.
T89C51RD2
61
Related parts for T89C51RD2-3CSCL
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
Part Number:
Description:
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
0 to 40MHz Flash Programmable 8-bit Microcontroller
Manufacturer:
ATMEL [ATMEL Corporation]
Datasheet:
Part Number:
Description:
0 To 40 Mhz Flash Programmable 8-bit Microcontroller
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
0 to 40MHz Flash Programmable 8-bit Microcontroller
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
Atmel CryptoMemory
Manufacturer:
ATMEL [ATMEL Corporation]
Datasheet:
Part Number:
Description:
Atmel CryptoMemory
Manufacturer:
ATMEL [ATMEL Corporation]
Datasheet:
Part Number:
Description:
Atmel CryptoMemory, 16Kbit
Manufacturer:
ATMEL [ATMEL Corporation]
Datasheet:
Part Number:
Description:
INTERVAL AND WIPE/WASH WIPER CONTROL IC WITH DELAY
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
Low-Voltage Voice-Switched IC for Hands-Free Operation
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
MONOLITHIC INTEGRATED FEATUREPHONE CIRCUIT
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
AM-FM Receiver IC U4255BM-M
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
Monolithic Integrated Feature Phone Circuit
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
Multistandard Video-IF and Quasi Parallel Sound Processing
Manufacturer:
ATMEL Corporation
Datasheet: