Final Connections for first spin

I would like to get the new ESP-12E modules soldered onto a board and start testing.  I have completed the basic schematic.  I added a reset switch, a switch to start in bootloader mode, Decoupling caps.

I moved the PC serial interface chip to a different part of the schematic to make it easier to read.  I added the Net Names TxD and RxD.  I added pull up and pull down resistors to make sure the chip would boot in the right mode.  Searching the web for boot modes showed that GPIO15 has to be pulled low during boot to load firmware. I think I can leave GPIO15 pulled low the rest of the time for normal operation. I also added a connector to the output pins and one for power.

I still want to add battery charging, and a switching boost regulator to generate VPP.  These can be left off at this time so that I can start laying out the board for fabrication.  This would not be normal in an engineering session, the whole design would be complete the first time the boards would be fabricated.

I found a really interesting boost regulator, the Skyworks Solutions AAT1230.  It would make the VPP circuit fairly easy to design.

Note: Decoupling caps are connected very close to the pins of a chip to reduce how much a sudden change in current can adversely affect a circuit.

Note: Net Names on schematics are used to say these lines are connected.  So TxD at the PC interface is also connected to TxD at the ESP-12E(Pin 21)

First Spin Sch

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.