The AAMP peripheral controls the volume and mute on the AAMP card.
Hardware:
Each AAMP card has a PAM8408 stereo class-D audio amplifier. The mute and up/down volume controls for the PAM8408 are computer controlled through the FPGA pins of a BaseBoard4. The AAMP card also has a computer controlled LED. More information about the AAMP is available here: /cards/aamp.html
Resources:
volume : the volume of the amplifier as a number in the range of 1 to 32. Gain values are shown below.
Volume Control (dB) value Gain value Gain value Gain 32 24 21 7.5 10 -10 31 22.5 20 6 9 -12 30 21 19 4.5 8 -14 29 19.5 18 3 7 -16 28 18 17 1.5 6 -18 27 16.5 16 0 5 -20 26 15 15 -1.5 4 -22 25 13.5 14 -3 3 -24 24 12* 13 -4.5 2 -26 23 10.36 12 -6 1 -80 22 9 11 -8enabled : a bit to enable (1) or disable (0) the amplifier. Note that a volume change can only occur when the amplifier is enabled. This resource works with pcset and pcget.
led : LED status as 1 (on) or 0 (off). This resource works with pcset and pcget.
Examples:
Set gain to 6 dB and turn the LED on.
pcset aamp enabled 1 pcset aamp volume 18 pcset aamp led 1