linux-works
hardware-based (arduino) SPI is now working. (mcp4822)
MUCH better, now! 5.8microseconds to set a 12 bit value to the dac over hardware-spi. (arduino 0022 has a bug in its SPI.cpp lib, sigh).
for demo, I set the step-size to 1024 so that you only get 3 levels on the wave. the hardware frequency counter on this scope reads 35khz. that means I was able to synthesize a crude 35khz wave (could be a nice sine after shaping) using a serial-based dac chip. or, that I can get data samples out 172,000 times per second! that was the real improvement when I enabled hardware SPI.
see:
www.flickr.com/photos/linux-works/7275918648/
for the software-only timing (264us vs 5.8us !)
hardware-based (arduino) SPI is now working. (mcp4822)
MUCH better, now! 5.8microseconds to set a 12 bit value to the dac over hardware-spi. (arduino 0022 has a bug in its SPI.cpp lib, sigh).
for demo, I set the step-size to 1024 so that you only get 3 levels on the wave. the hardware frequency counter on this scope reads 35khz. that means I was able to synthesize a crude 35khz wave (could be a nice sine after shaping) using a serial-based dac chip. or, that I can get data samples out 172,000 times per second! that was the real improvement when I enabled hardware SPI.
see:
www.flickr.com/photos/linux-works/7275918648/
for the software-only timing (264us vs 5.8us !)