Using Special Function Pins for GPIO on 3.2 with Audio Adaptor
- Thread starter bdoan
- Start date
KurtE
Senior Member+
If I am understanding your question correctly, you are asking if you have the Audio adapter setup on a Teensy 3.2, which uses several of the IO pins of the Teensy
to work, can you also use those IO pins for other GPIO functions....
If you look at the product page and at the Schematic, it gives you sort of an idea of what each pin is used for.
My guess is do not put an SDCard in the slot and do not populate the memory chip location on the board, that you can get away with
using the SPI pins and the two CS pins, for other purposes.
With the obvious caveat, that if you use SPI for other things like a TFT display, than the MOSI, MISO, and SCK (alternate 14) will be used.
That is pins (6, 7, 10, 12, 14), but note: there is 10K Pull up resistors on the two chip select pins pins 6 and 10
to work, can you also use those IO pins for other GPIO functions....
If you look at the product page and at the Schematic, it gives you sort of an idea of what each pin is used for.
My guess is do not put an SDCard in the slot and do not populate the memory chip location on the board, that you can get away with
using the SPI pins and the two CS pins, for other purposes.
With the obvious caveat, that if you use SPI for other things like a TFT display, than the MOSI, MISO, and SCK (alternate 14) will be used.
That is pins (6, 7, 10, 12, 14), but note: there is 10K Pull up resistors on the two chip select pins pins 6 and 10
MichaelMeissner
Senior Member+
Or even simpler, do not attach the SPI/CS pins to the audio adapter. Only attach the pins used by I2S or I2C devices, plus the power/ground pins.
Note however, if you aren't using the SPI pins for an actual SPI device, you may need to call the SPI library to turn off any initialization that the audio library did (including switching the SPI pins).
For I2C devices (pins 18/19) you can use other I2C devices as long as the devices do not use the 2 I2C addresses used by the audio adapter (0x0A, 0x1A). The audio adapter includes the pull-up resistors.
If you just need a few more pins, there are various boards that let you get at the bottom pads. FrankB designed this nice little PCB that lets you get to the bottom pins (10 digital pins, 2 analog pins, plus an extra 3.3v and ground pin):