GPIO Pin	Default Function on KC868-A6	Can Be Used for Custom IO?
GPIO0	BOOT button	Yes (with caution, as it affects boot).
GPIO2	Available	Yes
GPIO4	I²C SDA	Yes (if not using I²C).
GPIO5	Optional SPI CS	Yes
GPIO12	Available	Yes
GPIO13	Available	Yes
GPIO14	I²C SCL	Yes (if not using I²C).
GPIO15	I²C SCL (with strapping warning)	Yes, but avoid during boot issues.
GPIO16	UART RX (RS232)	No (used for RS232).
GPIO17	UART TX (RS232)	No (used for RS232).
GPIO18	SPI CLK	Yes (if not using SPI).
GPIO19	SPI MISO	Yes (if not using SPI).
GPIO21	Available	Yes
GPIO22	Available	Yes
GPIO23	SPI MOSI	Yes (if not using SPI).
GPIO25	Available	Yes
GPIO26	Available	Yes
GPIO27	UART TX (RS485)	No (used for RS485).
GPIO32	ADC (Voltage Sensor)	Yes (if analog input is needed).
GPIO33	ADC (Voltage Sensor)	Yes (if analog input is needed).
GPIO34	ADC (Voltage Sensor)	Yes (input-only).
GPIO35	ADC (Voltage Sensor)	Yes (input-only).
GPIO36	ADC (Voltage Sensor)	Yes (input-only).
GPIO39	ADC (Voltage Sensor)	Yes (input-only).





DI1	GPIO39	Digital Input 1
DI2	GPIO36	Digital Input 2
DI3	GPIO35	Digital Input 3
DI4	GPIO34	Digital Input 4
DI5	GPIO33	Digital Input 5 / ADC input
DI6	GPIO32	Digital Input 6 / ADC input
DA1	GPIO25	Analog Output (DAC1)
DA2	GPIO26	Analog Output (DAC2)
A1 (AI1)	GPIO39	Analog Input 1
A2 (AI2)	GPIO36	Analog Input 2
A3 (AI3)	GPIO35	Analog Input 3
A4 (AI4)	GPIO34	Analog Input 4
IIC (I²C)	SDA: GPIO4	I²C Data Line (shared for OLED)
SCL: GPIO15	I²C Clock Line (shared for OLED)
RS232 RX	GPIO16	UART RX for RS232 communication
RS232 TX	GPIO17	UART TX for RS232 communication
RS485 A	GPIO27	UART TX for RS485 communication
RS485 B	GPIO14	UART RX for RS485 communication
Relays 1-6	Internal	Controlled by GPIOs (relays are managed by the firmware).
3.3V/GND	Power	Power and ground connections for peripherals.