The VS1053 has 7 GPIO pins that can be read and written via the library.
The player_gpiotest sketch demonstrates how to do this. Be careful about pulling up GPIO1 - if the shield restarts when GPIO1 is connected to 3V logic, it will boot into 'MIDI' mode
The 7 GPIOs are by default pulled low with 100K resistors, and can only take up to 3V logic!
We can quickly demo the shield by slipping 3mm LEDs into alternating slots. Connect the positive (anode) to the 3V side of the dual strip
What? No current limiting resistors?
Strictly speaking, best practice is to use a current limiting resistor when driving an LED from a GPIO pin. In this case, the example sketch pulses each led only briefly, so there is no danger of damage. For more general use, you should select a resistor appropriate for the led you are using. See All About LEDs for more detail.
Run the player_gpiotest sketch
Connect the Arduino to your computer with a USB cable. Select File->Examples->Adafruit_VS1053->player_gpiotest to load the example code.Don't forget to uncomment the
Adafruit_VS1053_FilePlayer(SHIELD_RESET, SHIELD_CS, SHIELD_DCS, DREQ, CARDCS);line just like you did with the other examples.
If you have headphones, you will hear a beep at the start to indicate that the sketch is running. Then you should see the LEDs flashed in sequence.
If you open the Serial Monitor, you can see the values that are written to and read from each GPIO pin.
