Does anyone have a suggestion as to what would be a suitable protopying option for the SCM20100E?
I’d need some proto board on which I can solder the SCM20100E and at least a USB connector (perhaps the usb connector on a breakout board). Any suggestions for such prototyping boards?
If you have PCB design software, a 100x100 board from JLCPCB is about $4 plus shipping and 2 days manufacture. By far the best way to prototype as you can ensure that USB tracks use differential pairing and should be easier to solder a SUB connector too.
TBH, I am trying to avoid doing pcb design. I’ve done it in the past. But I learned …
A) I’m not good at it.
B) it costs me sooo much time. So many details …
C) I need the time for software and customer.
So, I hope it suffices to limit my hardware efforts to some prototyping by soldering stuff together on a breadboard. And when things work, I’ve had some PCB boards made in the past with the help of an engineer / pcb designer. The results were really OK, both technical and commercial. More complex stuff I need help from experts from the ground up ;-(
The VBUS provides +5V. In order to safely connect this to +3V3 pin 32, it must be regulated.
On the FEZ Duino this is done like in the 2 images above. First through the STPS140A and then using a LM1117MP-3.3. I assume the STPS140A provides extra safety for spikes / voltage reversals?
Since the SCM20100E does not have a +5V pin somewhere, the FEZ Duino setup is followed. As a result, a 3V3 is supplied to the SCM20100E on pin 32.
CC1 and CC2
On the FEZ Duino the CC1 and CC2 pins of the USB-C connector are each connected to a 5.1K resistor and then to GND.
This is a safe way of signalling to the USB host that nothing is going to be charged here? CC1 and CC2 are charging signals right?
These signals will be routed as in the SCM20100E prototype setup. They will go through 5.1K resistor to GND. They will not go into SCM20100E.
D- and D+
The D lines go directly to pin 45 and pin 46 of SCM20100E. On the schematics of the SCM20100E is see the following:
This means we have a resistor between the pin and the chip on board already.
So it is safe to connect directly from the USB connector to PIN 45 and 46?
The STPS140A is there to prevent the power from back feeding to the USB device that is connected when you use a bench or other power supply to power the board.
The resistors were mentioned before in another pos and should be documented with the modules etc. GHI should confirm their use if the documents don’t already indicate this. I think for the SOM they are included on the SOM but for the IC options, you need them.
Here is my first kicad schematic. Its for a carrier board for the SCM20100E module. My intent is to assemble it and connect this to my dev PC (which acts as the USB host, with VS2019), upload firmware, upload and debug an app and ultimately simply run the app on the SCM20100E.