document how to bring a v2p3 board up to current schematic

diff --git a/Notebook b/Notebook
index 2b35526dabb06036237b3ace3790853a1d089cc1..2e4042f82aebf2572c7158edbedb5841b34de108 100644 (file)
--- a/Notebook
+++ b/Notebook
@@ -495,3 +495,13 @@
 - note that the IP2326 boards I bought from Amazon pull up pin 12 with a 51k
   resistor to pin 13 (VIN), while I have those just directly connected.
 
+2025.07.20
+- updated PCB design to use v_usb for all FTDI power.  to achieve this on a
+  v2p3 board, cut the traces between the 3.3V vias on each side of the FTDI
+  chip before loading the chip.  After loading the chip, jumper pins 3, 10, 11
+  together.  This will use the internal LDO to provide VDDIO, and pull the
+  chip out of reset.  An open question is whether the Pi will be at all
+  bothered if no USB cable is attached and the FTDI chip is effective powered
+  down.  Will it try to self-power from the serial port pins and do something
+  odd as a result?  Hope not.
+