ZERO SOM/ZERO Evaluation Kit/Interfaces and Connectors/LCD

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History
Issue Date Notes
2026/01/08 First documentationrelease


LCD[edit | edit source]

Description[edit | edit source]

The LCD interface available on the Evaluation Kit at the connector J30.

J30 is a 40-pin 0.5mm pitch FPC connector.

On this connector are routed the RGB signals interface that operates in the RGB-666 color mode.


LCD connector

Signals[edit | edit source]

The following table describes the interfaces signals:

Pin# OSM ball Pin name Pin function Pin Notes
1,2,12,16,20,24,28
32,36,37,39,40
- DGND Ground
4,5,6 - 5V Power output
7,8 - 3V3 Power output
10 B_K3 RGB_HSYNC Horizontal sync this pin is routed - by default - to GND (and not connected to HSYNC)
11 B_L3 RGB_VSYNC Vertical sync this pin is routed - by default - to GND (and not connected to VSYNC)
13 B_M3 RGB_B5 B7 bit
14 B_N4 RGB_B4 B6 bit
15 B_M3 RGB_B3 B5 bit
17 B_P3 RGB_B2 B4 bit
18 B_R3 RGB_B1 B2 bit
19 B_R4 RGB_B0 B2 bit
21 B_T4 RGB_G5 G7 bit
22 B_T3 RGB_G4 G6 bit
23 B_U3 RGB_G3 G5 bit
25 B_V4 RGB_G2 G4 bit
26 B_V3 RGB_G1 G2 bit
27 B_W4 RGB_G0 G2 bit
29 B_Y4 RGB_R5 R7 bit
30 B_Y5 RGB_R4 R6 bit
31 B_AA5 RGB_R3 R5 bit
33 B_Y6 RGB_R2 R4 bit
34 B_AA6 RGB_R1 R2 bit
35 B_Y7 RGB_R0 R2 bit

Device mapping[edit | edit source]

  • LCD is typically mapped to /dev/fb0 device in Linux

Power sequence[edit | edit source]

Most of the LCD panels has many supplies and need a specific timing to power the rails and start the the signals.

The Evaluation Kit provides GPIO controlled power rails that can be leveraged both at bootloader and kernel level to meet any specifications.

The following sections describe the available rails:

+RGB_3V3[edit | edit source]

The most common voltage to supply the LCD panel internal logic. This rail is enabled by GPIO_C_5 that is connected to B_F4 OSM ball.

+RGB_5V[edit | edit source]

The most common voltage to supply the LCD panel backlight. This rail is enabled by GPIO_C_4 that is connected to B_F3 OSM ball.

Device usage[edit | edit source]

The display power sequence can be leveraged by a DAVE custom code that allow to set the timings both in U-boot and in Linux kernel sources.

The associated framebuffer device is accessed in Linux through the standard graphic access.