K3 Pico ITX

K3 Pico-ITX GPIO

Support level

K3 Pico-ITX is source-backed and build-tested, but remains limited until an exact production image and the 26-pin FPC are tested on hardware. Detection accepts the exact Device Tree identity model = "SpacemiT K3 Pico ITX" and compatible = "spacemit,k3-pico-itx".

This is intentionally not a general mapping of both FPC connectors. Only eight 3.3 V signals on the 26-pin connector are controlled by the application K3 GPIO block and exposed by the library. RT24-owned signals and the entire 1.8 V 36-pin connector remain unavailable.

Supported 26-pin FPC subset

Physical/BOARD mode uses the official 26-pin FPC positions. BCM-style mode uses the native K3 global GPIO/pad number. WiringPi logical pins 0-7 follow the supported physical pins in ascending order.

Physical	Official signal	Owner	Voltage	K3 GPIO	wiringPi	BCM-style	Current policy
1	3.3 V	Power	3.3 V	—	—	—	Unavailable
2	3.3 V	Power	3.3 V	—	—	—	Unavailable
3	R_I2C1_SCL	RT24	3.3 V	—	—	—	Unavailable
4	R_I2C1_SDA	RT24	3.3 V	—	—	—	Unavailable
5	GND	Power	—	—	—	—	Unavailable
6	R_UART0_TX	RT24	3.3 V	—	—	—	Unavailable
7	R_UART0_RX	RT24	3.3 V	—	—	—	Unavailable
8	GND	Power	—	—	—	—	Unavailable
9	UART5_TX	Application K3	3.3 V	21	0	21	Digital GPIO or UART mux
10	UART5_RX	Application K3	3.3 V	22	1	22	Digital GPIO or UART mux
11	R-PWM1	Application K3	3.3 V	28	2	28	Digital GPIO; hardware PWM not claimed
12	R-PWM2	Application K3	3.3 V	29	3	29	Digital GPIO; hardware PWM not claimed
13	UART10_TX	Application K3	3.3 V	31	4	31	Digital GPIO or UART mux
14	UART10_RX	Application K3	3.3 V	32	5	32	Digital GPIO or UART mux
15	UART10_CTS	Application K3	3.3 V	33	6	33	Digital GPIO or UART mux
16	UART10_RTS	Application K3	3.3 V	34	7	34	Digital GPIO or UART mux
17	GND	Power	—	—	—	—	Unavailable
18-25	R_CAN signals	RT24	3.3 V	—	—	—	Unavailable
26	GND	Power	—	—	—	—	Unavailable

The supported subset does not contain an application-CPU I2C or SPI bus. BPI-WiringPi2 therefore reports those board-level bus mappings as unsupported instead of silently opening a generic device node.

Evidence chain

• Official K3 Pico-ITX user guide and connector tables
• Official K3 Pico-ITX hardware resources
• Official schematic, SHA256 7e37c4a9d119a81b389d88f238cad13d4a1a8a6f5f83de2dcb5e34280289cd19
• Exact K3 Pico-ITX DTS at the audited SpacemiT kernel commit
• K3 pinctrl definitions
• SpacemiT GPIO driver, including spacemit,k3-gpio

The audited source is commit 27275ec8240cc49af3a525b8bc325d9b5029fb81, tagged k3-br-v1.0.0 on the k3-br-v1.0.y line.

Validation still required

Capture the exact image, kernel/DTB commit, model, complete compatible, gpiodetect, gpioinfo, /dev/mem permissions and library detection output. A hardware owner must approve an unoccupied 3.3 V pin before any output test, and must confirm the FPC orientation and breakout wiring.

Do not connect the 36-pin FPC to a 3.3 V adapter: its published IO domain is 1.8 V. Do not drive pins 3-7 or 18-25 through this library; they belong to RT24. Pull, alternate-function restoration, edge/PWM behavior and production-image permissions remain unverified.