Audio with Teensy 4.0 and PropShield

E

edotan

New member
Hi,

I have a Teensy 4.0 and a PropShield which I would like to directly solder to a speaker and play amplified sound. Is it possible to do it, or do I need to add an audio shield? Is there any guidance on it?

Many thanks.
 
It is problematical. The Teensy 4.0/4.1 does not have a DAC pin like the Teensy 3.2/3.5/3.6/LC microprocessors had. This means you can't just hook up the DAC pin to the prop shield and have it work.

Now, the Teensy has MQS pins, which can do audio to them. However, these pins are 10 (primary SPI CS pin) and 12 (SPI MISO pin). This means you can't use SPI. I.e., you can't use the 8 megabyte SPI flash drive on the prop shield, nor can you hook up a SPI display device to the primary SPI bus. You can use the secondary SPI bus, providing you are willing to solder wires to the underneath of the Teensy 4.0. The Teensy 4.1 brings out this secondary SPI bus to the outer pins.

The best way is to use either the audio shield (revision D), the PT8211 shield, or external I2S devices:

Hook up generally uses the I2S pins (7, 8, 20, 21, 23), and possibly I2C pins (18, 19). With the external I2S devices, you could also use the 2nd I2S bus (pins 2, 3, 4, 5, and pad 33 underneath the Teensy).

It might help if you describe what you are trying to make. Do you need the accelerometer, voltage level shifting, or flash storage in the prop. shield. Note, the level shifting (pins 11, 13) also prevents using the main SPI bus.
 
Many thanks for your prompt reply. Initially I was intending to use the PropShield in order to: a) control a led strip, b) output sound, c) use accelerometer.
However:
a) with the WS2812B led strip I found that Teensy 4.0 does a better / easier job controlling the led strip using FastLED.
b) thanks to your message, I understand that the PropShield won't be the right solution for audio.
hence I'm left with only needing the PropShield for its accelerometer.

I'm building a light saber for my kid, and learning in the process ;)

I don't mind adding an audio shield. I preferred staying away from it simply for size reasons, but given your answer I think I could still manage to fit the Teensy 4.0 + PropShield + AudioShield within the light saber's hilt.
If you have any other thoughts or suggestions, let me know. Otherwise I'll just go ahead with the Audio shield rev D.

Many thanks.

MichaelMeissner said:
It is problematical. The Teensy 4.0/4.1 does not have a DAC pin like the Teensy 3.2/3.5/3.6/LC microprocessors had. This means you can't just hook up the DAC pin to the prop shield and have it work.

Now, the Teensy has MQS pins, which can do audio to them. However, these pins are 10 (primary SPI CS pin) and 12 (SPI MISO pin). This means you can't use SPI. I.e., you can't use the 8 megabyte SPI flash drive on the prop shield, nor can you hook up a SPI display device to the primary SPI bus. You can use the secondary SPI bus, providing you are willing to solder wires to the underneath of the Teensy 4.0. The Teensy 4.1 brings out this secondary SPI bus to the outer pins.

The best way is to use either the audio shield (revision D), the PT8211 shield, or external I2S devices:

Hook up generally uses the I2S pins (7, 8, 20, 21, 23), and possibly I2C pins (18, 19). With the external I2S devices, you could also use the 2nd I2S bus (pins 2, 3, 4, 5, and pad 33 underneath the Teensy).

It might help if you describe what you are trying to make. Do you need the accelerometer, voltage level shifting, or flash storage in the prop. shield. Note, the level shifting (pins 11, 13) also prevents using the main SPI bus.
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