EarthLCD ezLCD-405, Руководство пользователя

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© 2016 Earth Computers Tech. Inc.
About the File ID:
File ID is returned in the response to the SD_FILE_OPEN command. It identifies the file after it
has been opened. Since maximum 2 files may be concurrently opened, the File ID should be: 1
or 2. Values higher than 2 are interpreted as 2 and 0 is interpreted as 1.
ezLCD Response
After receiving the SD_FILE_SEEK command, the ezLCD responds with either of the following
sequences:
In case of the success :
In case of an error :
The ezLCD response is sent through the same interface, which received the SD_FILE_SEEK
command.
Example:
The following sequence will advance the File Position Index by 23 bytes.
SD_FILE_SEEK 7C hex
1 1 dec (File ID)
23 23 dec (Offset LSB)
0 0 dec
0 0 dec
0 0 dec (Offset MSB)
Whence 1 dec (from the current File Position Index)
If the File Position Index has successfully been moved, the ezLCD responds with the following
sequence:
39 hex
In case of the failure, the following sequence will be sent by the ezLCD:
3E hex
7 6 5 4 3 2 1 0
0 0 1 1 1 0 0 1 Byte 0: 39 hex, 57 dec
7 6 5 4 3 2 1 0
0 0 1 1 1 1 1 0 Byte 0: 3E hex, 62 dec