[Tremor] Ogg Vorbis on AVR

[James Dabbs]

> AVR's are high performance 8 bit microcontrollers. They execute most 
> instructions in a single cycle (up to ~20MHz)  They have up to 128k 
> program memory (flash) and can address up to 64K RAM. It does not seem

> to have a HW multiplication instruction. This is probably the fastest
of 
> all microcontrollers, but it is still a microcontroller.

The AVR is about 5 times to slow to decode Ogg in real time.  You are
going to need to decode the data into a big memory buffer (SD Flash,
etc.) and then play it back.  (Since it has no DMA, just moving the
audio samples out of serial flash to an A/D at 44KHz is going to use up
a lot of CPU bandwidth.)

If real-time is important, I would look at an a Phillips LPC2106.  It's
close to the AVR's in size and cost, and its ARM7 core should be able to
keep up for most applications.