Charge SOM: Clarify current PP behavior

Signed-off-by: Stefan Wahren <stefan.wahren@chargebyte.com>

Author: lategoodbye

docs/source/hardware.rst

@@ -39,10 +39,13 @@ Control Pilot / Proximity Pilot (X18)
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 For ISO 15118 / DIN 70121 compliant communication between EVSE and PEV, Charge SOM supports
-CP (control pilot) and PP (proximity pilot) signaling including Green PHY communication.
+CP (control pilot) signaling including Green PHY communication.
 This Green PHY communication is available on network interface ``eth1``. The MAC address of
 this host interface is stored within the EEPROM on the Charge SOM.
 
+The PP (proximity pilot) monitoring from EVSE side is currently not implemented yet.
+So please leave this pin unconnected.
+
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 High-Voltage Connector (HVDC, X19)
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