Long-form RK3566 development board for bar and stretched displays. LVDS and
V-by-One display outputs, HDMI input, USB-C power and Wi-Fi 6 + BT 5.0 on a
narrow 170 × 51 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-LT66: its
connectors, pin assignments and electrical limits.
Connector map
RK3566 Cortex-A55 170 × 51 mm BL SPK MIC1 MIC2 RS485 RS232 CPU-USB USB2 USB3 IR+LED HDMI-IN GPIO RTC Light ADC LVDS DC TYPE-C OTG
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 14.0 CPU Rockchip RK3566 , 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 DDR LPDDR4 / LPDDR3, 2 GB / 4 GB Flash 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 Via USB-C to RJ45 adapter Screen interface LVDS (V-by-One header also fitted) HDMI HDMI in (Mini) RTC Yes — with scheduled power on/off Audio Audio out 2-channel, 2 × microphone Camera Via USB USB 1 × USB-C 3.0 / 1 × USB Micro OTG
Power: USB-C, 12 V / 3 A (current depends on screen size). A DC-in header
(§3.12) is also provided.
Internal expansion: 3 × USB 2.0, 2 × GPIO, 2 × MIC, speaker, RS232, RS485,
LVDS, DC-in, RTC, IR+LED, light-perception and V-by-One headers.
Board dimensions
Size 170 mm × 51 mm Thickness 2 mm Top clearance 6 mm Bottom clearance 4 mm
Serial ports at a glance
The RS232/TTL header and the RS485 header are driven through the standard serial
interface. The device node, where the datasheet gives one, is in the pin tables
below.
Port Device node Type RS232 / TTL (§3.8) /dev/ttyS0RS232 / TTL RS485 (§3.7) — RS485, half duplex
The RS485 device node is not specified in the datasheet. Confirm on your board
with ls /dev/ttyS* or contact us. 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)
3.17 V-by-One port — 51-pin, 0.5 mm
Pin Define Attribute Description 1 GND GND Ground 2 VBX1-7P Difference data Channel 7 3 VBX1-7N Difference data Channel 7 4 GND GND Ground 5 VBX1-6P Difference data Channel 6 6 VBX1-6N Difference data Channel 6 7 GND GND Ground 8 VBX1-5P Difference data Channel 5 9 VBX1-5N Difference data Channel 5 10 GND GND Ground 11 VBX1-4P Difference data Channel 4 12 VBX1-4N Difference data Channel 4 13 GND GND Ground 14 VBX1-3P Difference data Channel 3 15 VBX1-3N Difference data Channel 3 16 GND GND Ground 17 VBX1-2P Difference data Channel 2 18 VBX1-2N Difference data Channel 2 19 GND GND Ground 20 VBX1-1P Difference data Channel 1 21 VBX1-1N Difference data Channel 1 22 GND GND Ground 23 VBX1-0P Difference data Channel 0 24 VBX1-0N Difference data Channel 0 25 GND GND Ground 26 VB-LOCKN LOCKN Negative sampling clock 27 VB-HTPDN HTPDN HTPDN 28/29 NC NC NC 30 SEL_SECTION SEL_SECTION Data 31/32 NC NC NC 33 I2CM_C_SCL I2CM_C_SCL Data 34 I2CM_C_SDA I2CM_C_SDA Data 35 NC NC NC 36 BLON BLON BL- data 37 E-PWM_H E-PWM_H PWM- data 38–42 GND GND Ground 43 NC NC NC 44–51 V-by-One VCC VCC-12V VCC-12V
Backlight
3.2 Backlight Con port — PH1.25-6P
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
3.12 Power DC-in port — PH1.5-4P
This is the DC input, but its 12 V pins are labelled "Power Out" in the
datasheet. Feed 12 V in here — verify polarity before wiring.
Pin Define Attribute Description 1 GND GND Ground 2 GND GND Ground 3 VCC Power out 12V 4 VCC Power out 12V
3.14 RTC port — PH1.25-2P
Pin Define Attribute Description 1 VCC Power in 3.3V 2 GND GND Ground
Serial ports
The RS232/TTL and RS485 headers are driven through the standard serial interface.
The device API (ItempApiPub) does not handle UART I/O; it covers
power , display , GPIO ,
network and kiosk .
3.8 RS232 / TTL port — PH1.25-4P → /dev/ttyS0
Pin Define Attribute Description 1 VCC Power out 3.3V 2 RX I/O ttyS0 — UART RX 3 TX I/O ttyS0 — UART TX 4 GND GND Ground
3.7 RS485 port — PH1.25-4P
Pin Define Attribute Description 1 VCC Power out 3.3V 2 RS485-B I/O UART0 B 3 RS485-A I/O UART0 A 4 GND GND Ground
USB ports
Three internal USB headers, identical pinout (PH1.25-4P).
3.9 CPU_USB1 · 3.10 USB2 · 3.11 USB3 — PH1.25-4P
Pin Define Attribute Description 1 VCC Power out 5V 2 DM I/O USB D− 3 DP I/O USB D+ 4 GND GND Ground
Audio
3.4 Speaker port — PH1.25-4P
Stereo output (two channels).
Pin Define Attribute Description 1 LP Output Left SP2 negative 2 LN Output Left SP2 positive 3 RN Output Right SP1 negative 4 RP Output Right SP1 positive
3.5 MIC1 port — PH1.25-2P
Pin Define Attribute Description 1 P Positive Microphone positive 2 N Negative Microphone negative
3.6 MIC2 port — PH1.25-2P
Pin Define Attribute Description 1 P Positive Microphone positive 2 N Negative Microphone negative
LED, IR and sensors
3.16 IR + LED port — PH1.25-5P
Pin Define Attribute Description 1 IR Input IR input 2 GND GND Ground 3 VCC Power out 3.3V 4 LED-G LED green LED green 5 LED-R LED red LED red
3.13 Light-perception port — PH1.25-2P
Pin Define Attribute Description 1 ADC ADC ADC 2 GND GND Ground
GPIO
These are the pins the GPIO API drives. The SDK names
(GPIO_IO3–GPIO_IO5) match the Define column below.
3.3 GPIO Con1 port — PH1.25-3P
Pin Define Attribute Description 1 5V Power out 5V 2 IO I/O GPIO_I/O 3 GND GND Ground
3.15 GPIO Con2 port — PH1.25-5P
Pin Define Attribute Description 1 IO3 I/O GPIO_IO3 2 IO4 I/O GPIO_IO4 3 IO5 I/O GPIO_IO5 4 KEY I/O Power key 5 GND GND Ground
See GPIO for reading and driving these lines from code.
Other interfaces
3.18 Other ports
Interface Detail Power USB-C, 12 V / 3 A HDMI in HDMI Mini OTG USB Micro USB 1 × USB-C 3.0
Electrical specification
Parameter Min Typical Max Notes Power supply voltage — 12V — Ripple voltage — — — 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-LT66 support page .
