9600 bit/s UART
Cross RX and TX and share ground. The DFRobot example uses 8 data bits, no parity and one stop bit.
DFRobot DFR0299 reads audio from a microSD card and supports both serial commands and simple button control.
Left audio DAC output for an external audio input.
| Pin | Signal | Direction | Function |
|---|---|---|---|
| 1 | VCC Supply input | Supply input | Use a regulated 3.2–5 V supply. The speaker stage can draw more current while playing. |
| 2 | RX Input | Input | UART command input. DFRobot shows a series 1 kΩ resistor in the example. |
| 3 | TX Output | Output | UART response output. Use a receiver compatible with the module’s logic levels. |
| 4 | DAC_R Analog output | Analog output | Right audio DAC output for an external audio input. |
| 5 | DAC_L Analog output | Analog output | Left audio DAC output for an external audio input. |
| 6 | SPK1 Bridge output | Bridge output | One side of the amplified speaker output. Connect the speaker between SPK1 and SPK2. |
| 7 | GND Return | Return | Module ground. Share this reference with the UART controller. |
| 8 | SPK2 Bridge output | Bridge output | Other side of the amplified speaker output. Keep both speaker leads isolated from ground. |
| 9 | IO1 Input | Input | Ground momentarily for the previous track. A long press reduces volume in I/O mode. |
| 10 | GND Return | Return | Module ground. |
| 11 | IO2 Input | Input | Ground momentarily for the next track. A long press increases volume in I/O mode. |
| 12 | ADKEY1 Analog input | Analog input | First resistor-coded key input. Use the key resistance table for this module. |
| 13 | ADKEY2 Analog input | Analog input | Second resistor-coded key input. Use the key resistance table for this module. |
| 14 | USB+ USB data | USB data | Positive USB data contact for the supported storage interface. |
| 15 | USB− USB data | USB data | Negative USB data contact for the supported storage interface. |
| 16 | BUSY Output | Output | Playback status output. Low indicates playback in progress. |
| Parameter | Limit | Conditions and source |
|---|---|---|
| Supply voltage3.2–5 V | 3.2–5 V | The example uses 5 V. Allow headroom for playback current. DFRobot DFR0299 documentation, Pinout and Work Mode |
| StorageFAT16 or FAT32 · up to 32 GB | FAT16 or FAT32 · up to 32 GB | Insert or remove the card with power off. DFRobot DFR0299 documentation, Pinout and Work Mode |
| Serial mode9600 bit/s · 8N1 | 9600 bit/s · 8N1 | Use a 3.3 V logic UART and shared ground in the example. DFRobot Arduino example |
This guide follows the DFRobot DFR0299 module’s 16-contact pinout. Check the seller’s documentation for lookalike modules and different audio chips.