Update usbc.md

en/usbc.md

@@ -15,7 +15,7 @@ Traveler reports agree that the badge uses USB-C, the assumption is that this wa
 | ---------|------------|---------------------|-------------------------------------------------------|
 | SBU1     | A8         | SWDIO (GPIO)        | Primary use for SWD. Firmware can reconfigure to GPIO |
 | SBU2     | B8         | SWCLK (GPIO)        | Primary use for SWD. Firmware can reconfigure to GPIO |
-| RX1+     | B11        | ECG P               | ECG lines share a shielded pair.                      |
+| RX1+     | B11        | ECG P               | ECG P can be switched between this pin and the wristband via firmware |
 | RX1-     | B10        | ECG N               |                                                       |
 | TX1+     | A2         | ECG COM             | ECG common mode buffer output.                        |
 | TX1-     | A3         | -                   |                                                       |
@@ -24,12 +24,17 @@ Traveler reports agree that the badge uses USB-C, the assumption is that this wa
 | TX2+     | B2         | Reset               | Pull low to trigger a reset                           |
 | TX2-     | B3         | -                   |                                                       |
 
+# Schematics
+![USB-C related schematics section](/media/hardware/usb-c-pinout.png)
+
 **!Caution!** Most USB-C cables available for sale do not connect all pins of the connector. Whilst this is not a problem for general use, if you want to access the full available I/O contacts, it might be best to choose a cable from the suggestions listed at the bottom of the page.
 
 To use full I/O, there is a 'correct side up' for the USB-C cable.
 
+## SWD
 ## UART
 ## ECG
+## GPIOs
 
 ## 'Confirmed' full pin cable options
 Whilst this list does not guarantee you anything, these cables have been bought before and were found to have all contacts connected: