RK3568 development board for all-in-one digital signage and signage players.
Rich interface set — LVDS, EDP, MIPI, HDMI 2.0, dual USB 3.0, RS232/RS485,
SATA and PoE — on a 165 × 85 mm board.
This page is the hardware reference
Flashing, the firmware API and the guides
apply to every board. This page covers what is specific to the KTM-S68: its
connectors, pin assignments and electrical limits.
Connector map
RK3568 Cortex-A55 165 × 85 mm RJ11 x2 HDMI/RS232 AUDIO USB2.0 x2 USB3.0 x2 LAN KEY DC-POWER USB1 USB2 USB3 GPIO LVDS LVDS-BL MIPI EDP EDP-BL SATA SATA-PWR IR+LED MIC SPK RS232-1 RS232-2 RS232-3 RS485
Swipe sideways to see the whole board. Tap a connector to jump to its pin definition. Positions are schematic, not to scale.
Specification
OS Android 11.0 CPU Rockchip RK3568 , quad-core Cortex-A55 up to 2.0 GHzGPU Mali-G52 2EE — OpenGL ES 1.1/2.0/3.2, OpenCL 2.0, Vulkan 1.1 NPU Built-in, INT8 / INT16 hybrid operation RAM LPDDR4 / LPDDR3, 2 GB / 4 GB Storage eMMC 5.0, 8 GB / 16 GB / 32 GB Wi-Fi / BT 802.11 a/b/g/n/ac/ax + BT 5.0, 2×2 MIMO, dual 2.4/5 GHz Ethernet RJ45 gigabit (1000 M) Display LVDS, EDP, MIPI HDMI HDMI 2.0 out, up to 4K Audio 3.5 mm earphone + microphone Camera Via USB USB 2 × USB 2.0, 2 × USB 3.0 RTC Yes — with scheduled power on/off Video decode 4K P60 H.265 / H.264 / VP9 Video encode 1080P100 H.264 / H.265
Power: DC 12 V / 3 A via 5.5 mm barrel (current depends on screen size).
Internal expansion: 3 × RS232, RS485, 3 × USB 2.0, SATA 3.0, 6 × GPIO, speaker,
microphone, I2C, LVDS, EDP, MIPI, PoE.
Cashbox interfaces: RJ11-1 (DC 12 V / 1.5 A) and RJ11-2 (RS232).
Board dimensions
Size 165 mm × 85 mm Thickness 15 mm Top clearance 1.6 mm Bottom clearance 2 mm
Serial ports {#serial} at a glance
The three RS232 ports and the RS485 port are driven through the standard serial
interface. The device node for each is in the pin tables below — this is the
path your application opens.
Port Device node Type RS232-1 /dev/ttyS0RS232, full duplex RS232-2 /dev/ttyS6RS232, full duplex RS232-3 /dev/ttyS9RS232, full duplex RS485 UART0 RS485, half duplex
See the firmware API overview for how the device API drives
the board (power scheduling, GPIO, display, network, kiosk lockdown).
Display ports
Pin Define Attribute Description 1 5V Power out 3.3V / 5V / 12V optional 2 12V Power out 3.3V / 5V / 12V optional 3 3.3V Power out 3.3V / 5V / 12V optional 4 GND GND Ground 5 GND GND Ground 6 GND GND Ground 7 D0N Output Pixel 0 negative data (odd) 8 D0P Output Pixel 0 positive data (odd) 9 D1N Output Pixel 1 negative data (odd) 10 D1P Output Pixel 1 positive data (odd) 11 D2N Output Pixel 2 negative data (odd) 12 D2P Output Pixel 2 positive data (odd) 13 GND GND Ground 14 GND GND Ground 15 CLK0N Output Negative sampling clock (odd) 16 CLK0P Output Positive sampling clock (odd) 17 D3N Output Pixel 3 negative data (odd) 18 D3P Output Pixel 3 positive data (odd) 19 D5N Output Pixel 0 negative data (even) 20 D5P Output Pixel 0 positive data (even) 21 D6N Output Pixel 1 negative data (even) 22 D6P Output Pixel 1 positive data (even) 23 D7N Output Pixel 2 negative data (even) 24 D7P Output Pixel 2 positive data (even) 25 GND GND Ground 26 GND GND Ground 27 CLK1N Output Negative sampling clock (even) 28 CLK1P Output Positive sampling clock (even) 29 D8N Output Pixel 3 negative data (even) 30 D8P Output Pixel 3 positive data (even)
3.5 EDP port — dual-contact 20-pin, 2.0 mm
Pin Define Attribute Description 1 GND GND Ground 2 EDP_TX0N Difference data Channel 0 3 EDP_TX0P Difference data Channel 0 4 GND GND Ground 5 EDP_TX1N Difference data Channel 1 6 EDP_TX1P Difference data Channel 1 7 GND GND Ground 8 EDP_AUXN Data clock Difference signal 9 EDP_AUXP Data clock Difference signal 10 GND GND Ground 11 EDP_TX2N Difference data Channel 2 12 EDP_TX2P Difference data Channel 2 13 GND GND Ground 14 EDP_TX3N Difference data Channel 3 15 EDP_TX3P Difference data Channel 3 16 GND GND Ground 17 LCD_BL_PWM Backlight PWM Backlight PWM 18 GND GND Ground 19 VCC3V3_S0 3.3V VCC 3.3V VCC 20 LCD_RST Reset Reset
3.7 MIPI port — MIPI 40-pin, 0.5 mm
Pin Define Attribute Description 1 VCOM NC NC 2 VDD1 VCC 3.3V 3 VDD2 VCC 3.3V 4 GND1 GND Ground 5 RESET Reset LCD_RESET 6 NCP NC NC 7 GND2 GND Ground 8 D0N Output DSI_TX1_D0N 9 D0P Output DSI_TX1_D0P 10 GND3 GND Ground 11 D1N Output DSI_TX1_D1N 12 D1P Output DSI_TX1_D1P 13 GND4 GND Ground 14 CLKN Output DSI_TX1_CLKN 15 CLKP Output DSI_TX1_CLKP 16 GND5 GND Ground 17 D2N Output DSI_TX1_D2N 18 D2P Output DSI_TX1_D2P 19 GND6 GND Ground 20 D3N Output DSI_TX1_D3N 21 D3P Output DSI_TX1_D3P 22 GND7 GND Ground 23 NC NC NC 24 NC1 NC NC 25 GND8 GND Ground 26 NC2 NC NC 27 PWMO NC NC 28 NC4 NC NC 29 VCL NC NC 30 GND GND Ground 31 LED- LED K LED cathode 32 LED- LED K LED cathode 33 NC5 NC NC 34 NC6 NC NC 35 AVEE NC NC 36 NC7 NC NC 37 NC8 NC NC 38 AVDD3 NC NC 39 LED+ LED A LED anode 40 LED+ LED A LED anode
Backlight and display power
Selects the LVDS/EDP panel supply voltage by jumper.
Pin Define Attribute Description 1 3.3V LVDS VCC 3.3V 2 5V LVDS VCC 5V 3 12V LVDS VCC 12V
Pin Define Attribute Description 1 3.3V LVDS VCC 3.3V 2 5V LVDS VCC 5V 3 12V LVDS VCC 12V
3.4 Backlight Con1 port — PH2.0-6P
Pin Define Attribute Description 1 GND GND Ground 2 GND GND Ground 3 BL-ADJ Output Backlight adjust 4 BL-EN Output Backlight enable 5 VCC Power out 12V 6 VCC Power out 12V
3.6 Backlight Con2 port — PH2.0-6P
Pin Define Attribute Description 1 GND GND Ground 2 GND GND Ground 3 BL-ADJ Output Backlight adjust 4 BL-EN Output Backlight enable 5 VCC Power out 12V 6 VCC Power out 12V
Power and PoE
3.8 PoE port — PH2.54-4P
Pin Define Attribute Description 1 POE1 PoE PoE 1 2 POE2 PoE PoE 2 3 POE3 PoE PoE 3 6 POE4 PoE PoE 4
3.9 External power port — PH2.54-4P
Pin Define Attribute Description 1 12V Power in 12V 2 12V Power in 12V 3 GND GND Ground 4 GND GND Ground
USB ports
Three internal USB headers, identical pinout (PH2.0-4P).
3.10 USB1 · 3.11 USB2 · 3.12 USB3 — PH2.0-4P
Pin Define Attribute Description 1 GND GND Ground 2 DP I/O USB D+ 3 DM I/O USB D− 4 VCC Power out 5V
Serial ports
The RS232 and RS485 headers are driven through the standard serial interface —
open the device node listed for each. The device API (ItempApiPub) does not
handle UART I/O; it covers power , display ,
GPIO , network and kiosk .
3.13 RS232-1 port — PH2.0-4P → /dev/ttyS0
Pin Define Attribute Description 1 VCC Power out 3.3V 2 TX I/O ttyS0 — UART0 TX 3 RX I/O ttyS0 — UART0 RX 4 GND GND Ground
3.14 RS232-2 port — PH2.0-4P → /dev/ttyS6
Pin Define Attribute Description 1 VCC Power out 3.3V 2 TX I/O ttyS6 — UART TX 3 RX I/O ttyS6 — UART RX 4 GND GND Ground
3.15 RS232-3 port — PH2.0-4P → /dev/ttyS9
Pin Define Attribute Description 1 VCC Power out 3.3V 2 TX I/O ttyS9 — UART TX 3 RX I/O ttyS9 — UART RX 4 GND GND Ground
3.16 RS485 port — PH2.0-4P → UART0
Pin Define Attribute Description 1 GND GND Ground 2 RS485-A I/O UART0 A 3 RS485-B I/O UART0 B 4 VCC Power out 3.3V
Audio
3.17 MIC port — PH2.0-2P
Pin Define Attribute Description 1 N Negative Microphone negative 2 P Positive Microphone positive
3.18 Speaker port — PH2.0-4P
Pin Define Attribute Description 1 LP Output Left positive 2 LN Output Left negative 3 RN Output Right negative 4 RP Output Right positive
LED, IR and control
3.19 LED / IR port — PH2.0-5P
Pin Define Attribute Description 1 LED_R LED red LED red 2 LED_G LED green LED green 3 VCC Power out 3.3V 4 GND GND Ground 5 IRIN Input IR input
Storage — SATA
3.20 SATA port
Pin Define Attribute Description 1 GND GND Ground 2 TXP TXP Transmit positive 3 TXN TXN Transmit negative 4 GND GND Ground 5 RXN RXN Receive negative 6 RXP RXP Receive positive 7 GND GND Ground
3.21 SATA power port — PH2.0-4P
Pin Define Attribute Description 1 VCC Power out 12V 2 GND GND Ground 3 GND GND Ground 4 VCC Power out 5V
GPIO
3.22 GPIO port — PH2.0-8P
These are the pins the GPIO API drives. The SDK names (GPIO_A3
… GPIO_B0) match the Define column below.
Pin Define Attribute Description 1 GPIO_B0 I/O GPIO_B0 2 GPIO_A7 I/O GPIO_A7 3 GPIO_A6 I/O GPIO_A6 4 GPIO_A5 I/O GPIO_A5 5 GPIO_A4 I/O GPIO_A4 6 GPIO_A3 I/O GPIO_A3 7 Power key I/O Power key 8 GND GND Ground
Six user GPIO lines (GPIO_A3–GPIO_A7, GPIO_B0), plus a power-key line and
ground. See GPIO for reading and driving these from code.
Touch panel
3.23 TP I2C port — 10-pin
Pin Define Attribute Description 1 GND GND Ground 2 GND GND Ground 3 RST Reset Reset 4 INT Interrupt Interrupt 5 GND GND Ground 6 SCL SCL I2C clock 7 SDA SDA I2C data 8 VCC VCC 3.3V 9 GND GND Ground 10 GND GND Ground
Electrical specification
Parameter Min Typical Max Notes Power supply voltage — 12V — Ripple voltage — — 65 mV Power supply current — 2.5 A — Depends on screen size Power consumption — 30 W — Depends on screen size
API reference
The device API (power scheduling, GPIO, display, network, kiosk lockdown) is
documented under ItempApi reference . The serial ports above
are driven through the standard Android serial interface.
Downloads
Schematic, mechanical drawing and firmware image are on the
KTM-S68 support page .
