New Build

Update:

The level shifter came in this week.

Populating the board:

I installed parts out of my kit in the order that I grabbed them, until I had enough to do the basic test.  The board powered up and the blue LED on the ESP-12F blinked once.  Unfortunately the board wouldn’t program.

I started probing with my Oscilloscope.  The serial data lines looked normal when I tried to program the board. Then I looked at Reset and GPIO0 lines and found that GPIO0 was oscillating at 24 MHz. The Reset line was working as I expected it to.  I used a 1 MOhm resister as a pull down on GPIO15. I chose 1 MOhm to reduce the amount of current when A_Sel is High.  I knew this could cause me trouble, GPIO15 is used to put the chip into SD card mode. That may be too much resistance.  I changed that resistor to 10 KOhms to see if it made a difference. It did!

I uploaded the defaults, then my code. My simple serial menu came up in the terminal. With it working, I went on to populate the rest of the board.  I came up short 2 components, the pin header I use for the lithium cell and Q2.  I grabbed both of those from the last build and completed populating the board. I reconnected it to my computer, re-connected the serial terminal and the serial menu is still working.

SPI RAM Testing:

I re-enabled the SPI RAM test code uploaded it and forced a reset. I got a Hello World response. Enough said!

Looking forward:

The new board is assembled, and I know that the SPI and USB to serial bridge are working correctly.  The next step is getting the voltage regulation control loop running reliably.  I also need to get the Bill of Materials updated and do an inventory of components.  I have used some components from other projects on this one and used some from this project on others.

Conclusion:

Short post this week, most of my time spent on this project was soldering the components on the board.  I am looking forward to getting full functionality tested in the next few weeks.

Do you solder your own boards?  What does your bring up procedure normally look like?

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