at89c51snd1 ATMEL Corporation, at89c51snd1 Datasheet - Page 10

• Manufacturer Part Number: at89c51snd1
• Description: Mp3 Microcontrollers
• Manufacturer: ATMEL Corporation

Figure 5. Command Flow
Programming the Flash Data
Requests from Host
Answers from Bootloader
10
Sends Frame (Made of 2 ASCII
Characters per Byte)
Echo Analysis
AT89C51SND1 UART Bootloader
Sends First Character of the
Frame
Host
The flow described in Figure 6 shows how to program data in the Flash memory.
The bootloader programs on a page of 128 bytes basis when it is possible.
The host must take care that the data to program transmitted within a frame are in the
same page.
The bootloader answers with:
•
•
•
Command Name
“.” & “CR” & “LF” when the data are programmed
“X" & “CR" & “LF" if the checksum is wrong
“P" & “CR" & “LF" if the Security is set
Program Flash
":"
":"
Record
Type
00h
Address
Offset
Load
Start
Gets Frame, and Sends Back Echo
for Each Received Byte
nb of Data
Record
Length
Else
If (Not Received ":")
Sends Echo and Start
Reception
Bootloader
Data[0]
x
...
...
4241B–MP3–07/04
Data[127]
x