at89c5131a ATMEL Corporation, at89c5131a Datasheet - Page 23

• Manufacturer Part Number: at89c5131a
• Description: Usb Microcontrollers
• Manufacturer: ATMEL Corporation

Answers from Bootloader
Starting the Application
Request From Host
Answer from Bootloader
4287C–USB–11/04
The device has two possible answers to a DFU_GETSTATUS request:
•
•
The full chip erase is always executed whatever the Software Security Byte value is.
The flow described below allows to start the application directly from the bootloader
upon a specific command reception.
Two options are possible:
•
•
To start the application, the Host sends a DFU_DNLOAD request with the specified
application start type in the data field (3 or 5bytes).
This request is immediately followed by a second DFU_DNLOAD request with no data
field to start the application with one of the 2 options.
No answer is returned by the device.
Id_write_command
04h
If the chip is protected from program access, a “err_WRITE” status is returned to the
Host.
Otherwise, the device status is “OK“.
Start the application with a reset pulse generation (using watchdog).
When the device receives this command the watchdog is enabled and the
bootloader enters a waiting loop until the watchdog resets the device.
Take care that if an external reset chip is used the reset pulse in output may be
wrong and in this case the reset sequence is not correctly executed.
Start the application without reset
A jump at the address 0000h is used to start the application without reset.
Command
Identifier
SETUP
IN
OUT
SETUP
data[0]
03h
data[1]
AT89C5131A USB Bootloader
00h
01h
data[2]
Jump O
DFU_UPLOAD
ZLP
DFU_UPLOAD
address
data[3]
ption (3 or 5 Bytes)
data[4]
Hardware reset
LJMP address
Description
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