Getting Started

Communication Protocol Description

The player supports two communication interfaces: I2C and UART (switchable via jumper).

I2C Parameters:

• I2C Address: 0x35 (default)
• Commands: Sent as strings (e.g., ":p\r\n" for pause) via the TwiSend function.

UART Parameters:

• Baud Rate: 19200
• Data Bits: 8
• Parity: None
• Stop Bits: 1
• TTL Level: Required for PC connection (use a TTL/USB converter).

Mode Indication (LED):

• UART Mode: Green LED flashes once on startup.
• I2C Mode: Green LED flashes twice on startup.
• Ready State: Green LED stays lit.

UART/I2C Mode Switch

The interface mode of Player can be switched via the jumper.

I2C pin connection:

Analog Pin4 (SDA) goes to DO

Analog Pin5 (SCL) goes to DI

Supported Commands :

• Pause Play: ":p\r\n" → Returns "pause\r\n" if successful.
• Continue Play: ":s\r\n" → Returns "start\r\n" if successful.
• Play Next: ":n\r\n" → Returns "next\r\n" (success) or "false\r\n" (failure).
• Play Previous: ":u\r\n" → Returns "key up\r\n".
• Set Volume: ":v 255\r\n" → Sets volume (0 = minimum, 255 = maximum); returns "vol set ok" if successful.

Support SD Cards

The player has been tested with micro SD card (1G).

The SD card must be formatted at FAT format, not FAT32.

If the green led is flashing all the time which means the SD card is not ready, either not supported or not correctly formatted. And string "\Plese check micro SD card\r\n" will be returned in UART mode.

The player will only work if:

• There is a directory named "sound" in the root of the card that directory contains files ending in "wma", "wav", "mid" or "mp3".

• The blinking light signals not only problems reading the card, but it will also blink if there is no "\sound" directory or if there are no playable files in that directory.

If the green led do not flash, it means the SD card is working properly.