Second question regarding the LM4970; what is it expecting to see on the audio inputs for levels? Currently, for test, I'm using headphones right up to the input mic. At the device pin (after the cap) it shows 400mVp-p. MIDGAIN is set to "maximum" (whatever that means) and summing amp is set to 12dB. This results in the PWM section of the device seeing 1.6V "peaks", no? I hate to say it (being a fanboy of TI and all); this data sheet is "seriously lacking" in info.
For the record, settings:
PWM Freqt: 15KHz.
HPF cutoff: 3.5KHz. (with a 0.1uF cap for Cfilt).
Pattern select: audio sync. (I can blink the leds via I2C)
Current select: 2x, 2x, 2x
MGAIN: maximum
SGAIN: 12dB
Thanks.
