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Can DAC conversion of two separate channels be synchronised on the STM32G474 series?

MDaws.1
Associate

I'm working on a project to generate composite video from an STM32 using the high speed DACs.

This requires 3 DAC channels for red, green, blue fed by DMA.

Of course the red/green DMA conflicts with the blue, hence the blue output is delayed about 30ns. This would give a blue shift in the picture.

Can I separate the loading from the conversion to sync the separate DACs up?

i.e. DAC drives pre-loading data via DMA, but a separate signal drives the copying from holding register?

1 REPLY 1
Igor Cesko
ST Employee

Hi MDaws.1 (Community Member),

You must use timer trigger for DAC - this trigger transfers the data from holding register (where is transferred by DMA) to output data register. This timer trigger should be common for all DACs. Then output of all DACs should be synchronized (DMA timing can be a bit delayed - but timer trigger is fixed).

Regards

Igor