Using AMUX-es overcomplicates the project. I recommend to use two separate SAR_ADC and two DAC's on the receiving side (and, maybe, two separate UARTs for expense of one extra wire).
Using UART directly negates deterministic data output by VDAC, for higher quality, data better to be buffered on receiver side and transferred to DACs via DMA.
I forgot to mention that the communication between the two cards should be serial in order to replace wires with Leds later on. However, I will try to use what yuo said. Thank you
I agree. I also noticed Sami is using a AMux for the dithered VDAC output. Using a dithered VDAC generally requires an external RC on output to smooth out the dithering of the 8-bit VDAC being used. His TopDesign doesn't indicate a RC smoothing circuit and whether the Amux being used has maximum isolation.
Additionally with the dithering occurring, I'm not sure each output channel gets enough time with the DVDAC. There are multiple complications of syncing the one DVDAC to the output AMux.
Complications when you switch output channels:
- DVDAC Output signal settling time.
- DVDAC Output 'glitching' especially if output In_droit is significantly different than In_gauche.
- Syncing the switching of output AMux with the above mentioned settling time and glitching. You would need to turn off both channels In_droit and In_gauche until the output is stable before selecting the appropriate channel.
- Since AMux is not connected to the output 100% of the time, the RC smoother is driving a load (1K by standard conventions) which will dissipate the charge on the C when not connected to the DVDAC.
He might be able to get away with a AMux'd ADC but the two VDAC solution is almost required here.
The best he could do if he was required to use only one VDAC is to feed each of the outputs of the the two channel AMux (shown above) into a Peak-hold Opamp configuration.