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Apalis Carrier Board Design Guide
Toradex AG l Altsagenstrasse 5 l 6048 Horw l Switzerland l +41 41 500 48 00 l
l
Page | 35
2.6.3
Reference Schematics
2.6.3.1
24-bit Display Schematic Example
The parallel RGB interface can cause problems with EMC compliance when used with a high pixel
clock frequency. This can be made worse if a display is connected over flat flex cables. Therefore,
the flat flex cables should be kept as short as possible. Series resistors in the data lines reduce the
slew rate of the signals which instead reduces the radiation problem but can also introduce signal
quality and timing related problems. The serial resistor value is a trade-off between reduction of
electromagnetic radiation and signal quality. A good starting value is 22
Ω
.
Some displays feature an I
2
C interface for reading out the EDID PROM or additional controls such
as contrast and hue. If the carrier board provides no other display interface with DDC, it is
recommended that the I2C2 on the Apalis module be used for the DDC. If the DDC is used, make
sure that I
2
C device(s) on the RGB display do not interfere with the DDC address 50h. Otherwise,
use a different I
2
C interface on the Apalis module. The I
2
C interfaces on the Apalis module have a
3.3V logic level. If the display requires a 5V interface, add an I
2
C logic level shifter.
Figure 30: 24-bit parallel RGB display reference schematic
Display Connector
RESET_MOCI#
GND
GND
GND
GND
FH12-40S-0.5SV(55)
9
13
8
1
2
3
5
6
7
10
11
12
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
4
X2
LCD1_VSYNC
LCD1_HSYNC
LCD1_PCLK
LCD1_R2
LCD1_R3
LCD1_R4
LCD1_R5
LCD1_G6
LCD1_G7
LCD1_G2
LCD1_G3
LCD1_G4
LCD1_G5
LCD1_B6
LCD1_B7
LCD1_B2
LCD1_B3
LCD1_B4
LCD1_B5
LCD1_DE
LCD1_R7
LCD1_R6
PWM_BKL1
BKL1_ON
3.3V_SW
LCD1_B1
LCD1_B0
LCD1_G0
LCD1_G1
LCD1_R0
LCD1_R1
PCA9306DCTT
GND
1
VREF1
2
SCL1
3
EN
8
SDA1
4
SDA2
5
SCL2
6
VREF2
7
IC1
GND
R31
100K
100nF
16V
C2
GND
R33
1.8K
R32
1.8K
500mA
220R@100MHz
L1
500mA
220R@100MHz
L2
4.7pF
C4
4.7pF
C3
R35
1.8K
R34
1.8K
GND
I2C2_SCL
I2C2_SDA
I2C2_DDC_SDA_C
I2C2_DDC_SCL_C
100nF
16V
C1
I2C2_DDC[0..1]
3.3V_SW
22R
R36
22R
R38
3.3V_SW
5V_SW
MXM3_205
MXM3_207
MM70-314-310B1
Apalis - Display DDC
25 of 25
I2C2_SDA
205
I2C2_SCL
207
X1Y
I2C2_SDA
I2C2_SCL
22R
R37
22R
R39
MM70-314-310B1
POWER_ENABLE_MOCI
24
Apalis - System Control
4 of 25
RESET_MOCI#
26
RESET_MICO#
28
WAKE1_MICO#
37
X1D
MXM3_243
MXM3_245
MXM3_247
MXM3_249
MXM3_251
MXM3_253
MXM3_255
MXM3_257
MXM3_259
MXM3_261
MXM3_263
MXM3_265
MXM3_269
MXM3_271
MXM3_273
MXM3_275
MXM3_277
MXM3_279
MXM3_281
MXM3_283
MXM3_287
MXM3_289
MXM3_291
MXM3_293
MXM3_295
MXM3_297
MXM3_299
MXM3_301
MXM3_239
MXM3_286
MM70-314-310B1
LCD1_PCLK
243
Apalis - Digital RGB
12 of 25
LCD1_VSYNC
245
LCD1_HSYNC
247
LCD1_DE
249
LCD1_R0
251
LCD1_R1
253
LCD1_R2
255
LCD1_R3
257
LCD1_R4
259
LCD1_R5
261
LCD1_R6
263
LCD1_R7
265
LCD1_G0
269
LCD1_G1
271
LCD1_G2
273
LCD1_G3
275
LCD1_G4
277
LCD1_G5
279
LCD1_G6
281
LCD1_G7
283
LCD1_B0
287
LCD1_B1
289
LCD1_B2
291
LCD1_B3
293
LCD1_B4
295
LCD1_B5
297
LCD1_B6
299
LCD1_B7
301
BKL1_ON
286
BKL1_PWM
239
X1L
22R
R1
22R
R2
22R
R3
22R
R4
22R
R7
22R
R8
22R
R9
22R
R10
22R
R11
22R
R12
22R
R13
22R
R14
22R
R15
22R
R16
22R
R17
22R
R18
22R
R19
22R
R20
22R
R21
22R
R22
22R
R23
22R
R24
22R
R25
22R
R26
22R
R27
22R
R28
22R
R29
22R
R30
22R
R5
22R
R6
LCD1_VSYNC
LCD1_HSYNC
LCD1_PCLK
LCD1_R2
LCD1_R3
LCD1_R4
LCD1_R5
LCD1_G6
LCD1_G7
LCD1_G2
LCD1_G3
LCD1_G4
LCD1_G5
LCD1_B6
LCD1_B7
LCD1_B2
LCD1_B3
LCD1_B4
LCD1_B5
LCD1_DE
LCD1_R7
LCD1_R6
PWM_BKL1
BKL1_ON
LCD1_B1
LCD1_B0
LCD1_G0
LCD1_G1
LCD1_R0
LCD1_R1
LCD[0..29]
5V_SW
3.3V_SW
V_DDC
V_DDC
V_DDC
1
2
3
JP1