Talk - Technical
The circuit above shows the wiring for the audio output of SCBP.
The MAX98357A IC is a Class D amplifier which takes an input from Pulse Code Modulated (PCM) data.
The PCM clock (SAI1_SCK) comes in on BCLK.
The PCM Stereo data (SAI1_SD) comes in on DIN.
LRCLK (SAI1_FS) indicates whether the current PCM sample belongs to the left or right audio channel.
VDDF is the 5V supply from USB. It is buffered internally so if you pull too much power from it,
and you know you will, it will trip and need to be reset with the pushbutton when you've turned it down.
The two MAX98357As share the same digital audio stream. Their SD_MODE pins are strapped differently
so one reproduces the left channel and the other reproduces the right channel.
The two resistors, R12 and R13 have been calculated using the MAX98357A datasheet to set each
of the ICs to the correct channel, left and right.
The code