HiFiBerry Amp 2

WARNING: DO NOT use the Raspberry Pi's 5V power supply connected to the Micro-USB port of the Raspberry Pi.

Use a 12V barrel power supply connected to the HiBerry Amp 2. The Raspberry Pi will be powered by the HiBerry Amp. Do not connect power supply to HiBerry AMP 2

Step 1. Mount the HiBerry Amp 2

Shutdown the Raspberry Pi

$ sudo shutdown now

Wait for the lights to stop blinking

Remove the micro USB power supply from the Raspberry Pi

Mount the HiBerry Amp 2 on top of the Raspberry Pi

Step 2. Make connections

I am only using a single speaker and a 12V barrel power supply:

Step 3. Configure raspbian to work with HiBerry AMP 2

Edit config.txt

$ sudo nano /boot/config.txt

and comment out the line

# dtparam=audio=on

and at the end of the file add the lines

# HiBerry AMP 2

dtoverlay=hifiberry-dacplus

CTRL-o, ENTER, CTRL-x to save and exit the editor

and then reboot:

$ sudo reboot

Step 4. Check if sound card is installed

This command will check if the sound card is installed

$ aplay -l

**** List of PLAYBACK Hardware Devices ****

card 0: sndrpihifiberry [snd_rpi_hifiberry_dacplus], device 0: HiFiBerry DAC+ HiFi pcm512x-hifi-0 []

Subdevices: 1/1

Subdevice #0: subdevice #0

Step 5. Check if it works

HiBerry Amp 2 Pins used:

• I2C (GPIO 2, 3) SDA and SCL pins 3 and 5 are used to control the HiBerry Amp 2

• GPIO 4 is used to control the MUTE function of the power stage. Pulling it low mutes the output.

• GPIOs 18-21 (pins 12, 35, 38 and 40) are used for audio interface

• Pin 27 and 28 are always reserved for an ID EEPROM Since over-the-air FM Radio uses I2C, I will need to figure out how to use HiBerry Amp 2 and Si4702 as I2C slave devices.