For work I am going to try and restore the canned messages in some ISD5100 ChipCorder modules. We have some good ones and I hope to read one and overwrite the bad ones. The modules have a 2.8 volt regulator and I am not sure if the Teensy will just work have have issues talking to it via its I2C interface. Should my pull up resistors go to 2.8v or the Teensy's 3.3V? I am thinking of using an Audio adaptor with to store the analog messages in the optional flash chip. How long of a playback can I get ? If needed I could add a SD card I guess. The messages I need to restore are a only about 4 seconds each and there are about 8 of them.
Audio Adaptor flash chip playback length, Teensy 3.2 to a 2.8v I2C chip
- Thread starter DaQue
- Start date
- Status
PaulStoffregen
Well-known member
Teensy 3.2 can run with only 2.8 volts. But the USB might not work below 3.0V.
Of course if the VIN-VUSB pads are still connected, and you connect a USB cable with 5V power, the regulator will try to put 3.3V onto the power line, probably over-driving, possibly damaging whatever 2.8V stuff you have.
If you use a 128M flash chip, it gives 16 Mbyte space. Each second of uncompressed 44.1 kHz 16 bit sound requires 88.2 kbytes, so that chip could store about 185 seconds. Should be plenty to hold those 8 clips if they're only 4 seconds each.
Of course if the VIN-VUSB pads are still connected, and you connect a USB cable with 5V power, the regulator will try to put 3.3V onto the power line, probably over-driving, possibly damaging whatever 2.8V stuff you have.
If you use a 128M flash chip, it gives 16 Mbyte space. Each second of uncompressed 44.1 kHz 16 bit sound requires 88.2 kbytes, so that chip could store about 185 seconds. Should be plenty to hold those 8 clips if they're only 4 seconds each.
Thanks I wasn't sure about i2C. It's basically open collector with external pull ups isn't it? If I configure all the other teensy outputs going to the module to open collector with pull ups to 2.8v would that work? I am assuming digital output from it at 2.8 v would be close enough for the Teensy inputs. I better make room to hack in a couple level shifters if not.
- Status