[SOLVED] STM32F205 DAC Speed

[sm23]

Posted on July 04, 2014 at 10:20

I am using the code from the DAC with DMA example in the Standard Peripheral Library V1.1.0 to produce a sine wave. The updates seem to occur about every 4.5us.

Is it possible to significantly increase the update speed with this device? I'm looking for updates at more like 2MHz rather than the <250KHz that I'm getting. Thanks in advance#dac #dac-dma

[frankmeyer9]

Posted on July 04, 2014 at 10:40

Is it possible to significantly increase the update speed with this device?

Theoretically yes, but practically not. Check the datasheet for the DAC settling time. I can't cite the exact number from memory, but it's around 5us. The DAC, as implemented in the STM32, just will not go faster. For significantly faster output, you need exteral devices.

[sm23]

Posted on July 14, 2014 at 14:10

Thanks!

[hossam]

Posted on March 12, 2015 at 12:00 Is it possible to reduce the number of bits per sample or reduce the reference voltage in order to increase the data rate?

[AvaTar]

Posted on March 12, 2015 at 12:16

Is it possible to reduce the number of bits per sample or reduce the reference voltage in order to increase the data rate?

Because the datasheet speaks of shorter settling times for LSB changes, compared to full-scale ? There are still the same RC constants at work, and you would lose more (in regard to resolution and SNR), than you possibly gain. And, expect significant variations in settling time over temperature and between individual chips. Not sure if you can change the reference voltage, look it up in the reference manual. If the internal DAC doesn't match your specs, rather consider an external device.

[Tesla DeLorean]

Posted on March 12, 2015 at 13:13

I'm sure one could characterize the behaviour.

It uses the same VREF as the ADC, so you could perhaps change that.User DarthVader built a 3 channel VGA DAC using a Resistor Ladder configuration.