Toradex Colibri - Parallel RGB LCD Signals; Reference Schematics

Colibri Carrier Board Design Guide
Toradex AG l Altsagenstrasse 5 l 6048 Horw l Switzerland l +41 41 500 48 00 l www.toradex.com l info@toradex.com
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2.4.1 Parallel RGB LCD Signals
Colibri
Pin
Colibri
Signal Name
I/O
Type
Power
Rail
Description
52
LCD_1_18bit_R0
O
CMOS
3.3V
Red LCD data signals (LSB: 0, MSB: 5)
54
LCD_1_18bit_R1
O
CMOS
3.3V
66
LCD_1_18bit_R2
O
CMOS
3.3V
64
LCD_1_18bit_R3
O
CMOS
3.3V
57
LCD_1_18bit_R4
O
CMOS
3.3V
61
LCD_1_18bit_R5
O
CMOS
3.3V
80
LCD_1_18bit_G0
O
CMOS
3.3V
Green LCD data signals (LSB: 0, MSB: 5)
46
LCD_1_18bit_G1
O
CMOS
3.3V
62
LCD_1_18bit_G2
O
CMOS
3.3V
48
LCD_1_18bit_G3
O
CMOS
3.3V
74
LCD_1_18bit_G4
O
CMOS
3.3V
50
LCD_1_18bit_G5
O
CMOS
3.3V
76
LCD_1_18bit_B0
O
CMOS
3.3V
Blue LCD data signals (LSB: 0, MSB: 5)
70
LCD_1_18bit_B1
O
CMOS
3.3V
60
LCD_1_18bit_B2
O
CMOS
3.3V
58
LCD_1_18bit_B3
O
CMOS
3.3V
78
LCD_1_18bit_B4
O
CMOS
3.3V
72
LCD_1_18bit_B5
O
CMOS
3.3V
44
LCD_1_18bit_DE
O
CMOS
3.3V
Data Enable (other names: Output Enable)
56
LCD_1_18bit_PCLK
O
CMOS
3.3V
Pixel Clock (other names: Dot Clock, L_PCLK_WR)
68
LCD_1_18bit_HSYNC
O
CMOS
3.3V
Horizontal Sync (other names: Line Clock, L_LCKL_A0)
82
LCD_1_18bit_VSYNC
O
CMOS
3.3V
Vertical Sync (other names: Frame Clock, L_FCLK)
Table 7: Parallel RGB LCD Signals
2.4.2 Reference Schematics
2.4.2.1 18-bit Display Schematic Example
The parallel RGB interface can cause problems in passing the electromagnetic radiation tests when
used with high pixel clock frequency, especially if a display is connected over long flat flex cables.
The reduction of radiation needs to be taken into account. Keep the flat flex cables as short as
possible. Series resistors in the data lines reduce the slew rate of the signals, which reduces the
radiation problem but can introduce signal quality and timing problems. The serial resistor value is
a trade-off between electromagnetic radiation reduction and signal quality. A good starting value
is 22Ω.