I need to drive an analog VCO chip with a time varying voltage based on arbitrary waveforms (for frequency control, LFO type)
The problem using a DAC for anything other than a DC voltage is that its registers needs to be updated continually at fixed time intervals.
If the DAC is Arduino controlled, that works well (circling through a lookup table) unless the MCU does anything intensive in the meantime, which is the case, that leads to delay problems.
As far as I know, here are my options :
-use a Raspberry Pi, or any MCU sufficiently fast (80+ Mhz CPU) with multithreading/RTOS option so that the timing discrepancies are not perceptible.
-use a MCU per DAC and one main MCU to rule them all. (with serial communication between the main / dedicated MCUs), making my own DDS in the process.
-use a DDS+DAC IC that is capable of executing repeatedly a waveform pattern, load the pattern once for all from the MCU until an update in the waveform is needed.
I would preferably go for option 3, because of the lower footprint.
I've looked at AD9106 but it seems real overkill for my application (the fundamental frequency of the repeating pattern would be in the LFO range, that is, up to 50 Hz at most)
Any ideas for a relatively simple DDS or even an advanced DAC with a repeating pattern feature ?
The problem using a DAC for anything other than a DC voltage is that its registers needs to be updated continually at fixed time intervals.
If the DAC is Arduino controlled, that works well (circling through a lookup table) unless the MCU does anything intensive in the meantime, which is the case, that leads to delay problems.
As far as I know, here are my options :
-use a Raspberry Pi, or any MCU sufficiently fast (80+ Mhz CPU) with multithreading/RTOS option so that the timing discrepancies are not perceptible.
-use a MCU per DAC and one main MCU to rule them all. (with serial communication between the main / dedicated MCUs), making my own DDS in the process.
-use a DDS+DAC IC that is capable of executing repeatedly a waveform pattern, load the pattern once for all from the MCU until an update in the waveform is needed.
I would preferably go for option 3, because of the lower footprint.
I've looked at AD9106 but it seems real overkill for my application (the fundamental frequency of the repeating pattern would be in the LFO range, that is, up to 50 Hz at most)
Any ideas for a relatively simple DDS or even an advanced DAC with a repeating pattern feature ?