[sdiy] In praise of the ATM STM32F303

[Colin f]

> -----Original Message-----
> From: Olivier Gillet [mailto:ol.gillet at gmail.com]
> Sent: 12 February 2016 14:53
> Subject: Re: [sdiy] In praise of the ATM STM32F303
> 
> If you're only interested in pure digital generation, you don't even have to
> use this feature - you can also directly alter the frequency of the timer that
> clocks the DAC updates.
 
> Colin's suggestion is about using an external clock source, such as a VCO, to
> clock the reads.

Indeed - this method is useful where you have external clocking.
For an oscillator, you might use a divider and PLL to multiply the frequency of an analogue oscillator and add a sampled waveform option.
For regularly clock sample and hold applications, you could have a simple CMOS oscillator drive a counter chip drive a timer that selects analogue mux channels, and have the DAC output clocked by that circuit.
Then the CPU need do nothing more than write values to the block of RAM that is DMA'd to the S&H.
Could be useful if you are doing other things that need all the CPU you can get.
The STM32 also does nice DMA of ADC channels, so you can set & forget a range of pins to be sampled by the ADC, and the values just appear in an array without any CPU demand.
Great little chips ;)

Cheers,
Colin