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E-mail: [email protected]
Flyron Technology Co., Ltd.
FN-BC04 MP3 Sound Module with 10W Amplifier
7
Format:
$S / Ver. / Number / Command / Feedback / Param_MSB / Param_LSB / Check_MSB / Check_LSB / $O
$S
Start byte 0x7E
Ver.
Version byte, 0xFF by default
Number
Number of bytes from version info to Check_LSB, typically 0x06 (checks um not counted)
Command
Command byte
Feedback
0x01: Need feedback --send confirmation back to MCU; 0x00: No need feedback
Param_MSB
Most significant byte of parameter
Param_LSB
Least significant byte of parameter
Check_MSB
Most significant byte of checksum
Check_LSB
Least significant byte of checksum
$O
End byte 0xEF
For example, if we specify playback of SD card, we need to send the command “7E FF 06 09 00 00 02 FF F0 EF”. The number
is 6 bytes, and these 6 bytes are “FF 06 09 00 00 02”. Start byte, end byte and checksum are not counted.
4.3. About Checksum
Regarding to calculating checksum, you can use the following formula to count.
Checksum (2 bytes) = 0xFFFF–(CMD + Fe Pa Para_LSB) + 1
Normally it’s okay whether users choose to use checksum or not, our module can receive a serial data with or without checksum,
but some of users use a MCU without crystal oscillator, so if in that case we strongly suggest users to add checksum to make sure
the communication stability.
4.4. Serial Communication Commands
4.4.1. Control commands
Command
Function
Note
0x01
Play Next
0x02
Play Previous
0x03
Specify playback of a track
See 4.6.1 for details
0x04
Increase volume
0x05
Decrease volume
0x06
Specify volume
See 4.6.2 for details
0x08
Specify single repeat playback
See 4.6.3 for details
0x09
Specify playback of a device
See 4.6.4 for details
0x0A
Set sleep mode
See 4.6.5 for details
0x0B
Awake from sleep
0x0C
Reset
