RTC keeps time between POWER OFF & ON, SD Card at start still needs work -- if card is in the slot, it is not readable until it is pulled on and then inserted.

exercises/06_RTC_check/platformio.ini

@@ -0,0 +1,31 @@
+; 20260214 ChatGPT
+; $Id$
+; $HeadURL$
+
+[platformio]
+default_envs = node_a
+
+[env]
+platform = espressif32
+framework = arduino
+board = esp32-s3-devkitc-1
+monitor_speed = 115200
+lib_deps =
+  lewisxhe/XPowersLib@0.3.3
+
+build_flags =
+  -D I2C_SDA1=42
+  -D I2C_SCL1=41
+  -D RTC_I2C_ADDR=0x51
+  -D ARDUINO_USB_MODE=1
+  -D ARDUINO_USB_CDC_ON_BOOT=1
+
+[env:node_a]
+build_flags =
+  ${env.build_flags}
+  -D NODE_LABEL=\"A\"
+
+[env:node_b]
+build_flags =
+  ${env.build_flags}
+  -D NODE_LABEL=\"B\"