Member Since: May 11, 2012

Country: United States

  • Apparently the Sparkfun MP3 Player Shield and the MP3 Trigger have a “ground loop” vulnerability when connecting a power amplifier to the speaker connection. The fix for this problem (as documented by VLSI) requires the addition of two capacitors and four resistors to the speaker output lines. Does the WAV Trigger have a similar problem? Is it safe to connect the headphone and speaker output to an amplifier or powered speakers without the risk of a ground loop (or anything similar) that could damage the board? I am aware that you can enable/disable the onboard 2W mono amplifier, so of course the question regarding the speaker output assumes no onboard speaker amplification.

  • The internal clock runs at 8 MHz, but it comes from the factory programmed to divide this 8 MHz clock by 8 which results in the chip running at 1 MHz You can make it run at the full 8mHz speed (without using an external clock) by modifying one of the fuse values. Refer to this link: Change the value of low fuse (LFUSE) from 0x62 to 0xE2. You can do this with Avrdude and a programmer that can deal with the Attiny84, or a programmer like the AVRISP MKII with the driver and programming interface that accompanies Atmel Studio (which can be downloaded free).

No public wish lists :(