[Solved] Using a DAC (MCP4911) instead of a low-pass filter

i thought i'd make new topic, last 1 got messy.

i have decided use true d/a converter convert arduino's pwm output analog, rather low-pass filter have set up. not sure how go using it, 1 have ordered uses spi... , ethernet shield uses spi well.

the single pwm output, after being smoothed, go scaling circuit (which scales 0-5v +/-10v), , servo-amplifier, output being control signal. not think control loop running @ faster 100 hz, , hoping write microsd card @ same rate.

my question - if ethernet shield using spi, , dac should using spi, better connect dac spi pins (with different ss, of course!), or go software approach, using maybe shiftout() function, or library 1 attached in a previous post. i've spent whole night reading old topics different approaches spi, , datasheet dac ordered, no closer decision several hours ago! appreciate advice  

thanks,
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there's no reason 2 shouldn't both work on hardware spi long deal ss issue. otoh code may bit simpler if use shiftout() because won't have deal ss.

as long don't need speed see no real advantage either way.

at rate need write dac?

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rob

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