Audio Adaptor REV B - missing documentation


Active member
Hello all / Paul,
we are working with several teensy audio boards and realized that most of those are actually a new hardware revision REV B, for which there is no explicit documentation yet.

The apparent changes to the board itself are fairly minor:
  1. two resistors in series between pin 10 and 3.3V, 10kOhm in total -> hardware pullup
  2. cuttable traces on pin 13 (teensy I2S RX) and pin 22 (teensy I2S TX)
  3. cuttable trace / solder bridge alternative connecting the SGTL5000 AGND (chip pin7) to the regular GND (default) or 3.3V (option)
Anyway, keep up the good work!
Yup, pullups were added to both the chip select signals. It was a matter of try to follow my own advice on SPI bus design.

Those cuttable jumpers are meant to allow changing the I2C address, and to separate the I2S transmit and receive, possibly allowing them to be wired somewhere else. In theory, Teensy 3.1 might be able to support two audio boards (for quad channel input & output), using the same 3 clock signals, but with the TX & RX data on different pins. Maybe? So far, no work has been done on the software side, which is the main reason I haven't bothered to document those jumpers.