[DAC Board] Rev C Design Review #1 - Schematic

Severson-Group / AMDC-Hardware

Circuit board designs for controlling advanced motor systems

http://docs.amdc.dev/hardware

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[DAC Board] Rev C Design Review #1 - Schematic #207

Closed codecubepi closed 2 years ago

codecubepi commented 2 years ago

Revision C Overview

This PR is for the first Design Review of Revision C of the DAC Board, focused on the schematic primarily, but also on the new component placement on the PCB.

Two major fixes have been addressed in the Revision C design:

Replacement TVS diode components have been implemented to fix voltage readout errors caused by the previous TVS diodes in the design (see #204)
The 15-pin connector circuitry has been updated to allow the DAC expansion board to connect to the AMDC via either the PowerStack or the GPIO Ports, replacing the "IsoSPI" connection interface from DAC Rev B (see #200)

Updated Schematics - PDF Link

Output Connectors Schematic - New TVS Diodes

Input Connectors Schematic - New 15-Pin Connector Circuitry

PCB 3D Captures

Top - See U2, C3, C4

Bottom - See U13, C42

BOM Details

Estimated cost per board is $91.91 with parts from DigiKey. See the BOM here.

codecubepi commented 2 years ago

@npetersen2

Yeah I think a dip switch (like this one?) would be a simple way to cut off those signals to U13.

And I'm not sure I 100% understand the AM26 G/~G pins... would I just connect ~G to GND? We want it to operate all the time right? Or am I not understanding the purpose of those pins?

npetersen2 commented 2 years ago

@codecubepi

Yes, a DIP switch like the one you linked looks nice.
Per the AM26C32 datasheet on page 1 and 8 and 9:

I believe, in your schematic, you tie both G and !G low, meaning that you have selected ACTIVE LOW mode. This means that when the differential voltage between A and !A is positive, the output is logic 1, and vice versa.

Please confirm the setting for how this is configured on the TX side on the AMDC and confirm the TX and RX sides are configured the same

codecubepi commented 2 years ago

@npetersen2 Okay, I added the SDA06H0SBR 6-position DIP switch to allow the cutoff of the Power Stack signals to prevent damage to U13.

I've also tied only the !G signal to GND on the DAC board's U13 sig-diff. It now matches the AMDC's AM26C32 sig-diff components.

Please review when you can, and I'd definitely like to meet to go over the PCB trace routing. It's spaghetti to me...