Cherry Zheng

MY-IMX6 motnherboard layout instruction

Discussion created by Cherry Zheng on May 3, 2018

MY-IMX6 motnherboard layout instruction

This document is for users to have a quick design of base board,with guidance for how to solve the questions clients may meet commonly,in order for clients to design a product which can be used in all kinds of environments。

power supply

 

schematic

  
MY-I.MX6 series of core board only needs 5V power source(constant current is not small than 2A,peak value 2.5A-3A)as an input。details as below。
Myzr dibansheji 1.1.0.1.png


if it is a direct 5V input,5V power source need a over voltage protection,the protection circuit can be designed with following reference。
Myzr dibansheji 1.1.0.2.png


  if it is high voltage input to be converted to 5V through DCDC principle,the core board will output 3P3V power source with a maximum current 500mA of which can be used as power supply for base board if current with 3.3V on the base board is too small,in this case,please put in serial a fuse for this 3P3V power source 。
  since current with 3.3V on the base board is usually over 500mA,normally users will generate a another 3.3V through DCDC or LDO。
  note:enable control must be done for 3.3V on base board by 3P3V on core board instead of being conducted by other power sources on the base board.if there are other power sources on base board,their enable controls must be conducted by 3P3V as well,this is up to the nature of I.MX6 chip。
  reference circuit as below:
Myzr dibansheji 1.1.0.3.png

PCB

  capacitor with big capacity should be placed near 5V input on core board, to ensure contiguous power supply even when sudden extra load is added for CPU。if there is via hole,need to make sure via hole can go through 3A peak current,more via holes can be built to increase current。

serial port design

 

principle

for serial port design,common questions arising are inversion between RXD and TXD。network standard in the schematic as below


Myzr dibansheji 2.1.0.1.png

TXD——CPU output
RXD——CPU input

PCB

  note:we can provide schematic and PCB diagram for design of base board,our serial port is female head as connector.please assure your design to be consistent with our offer,if change serial port to be male head connector,then RS232 signal connector head need to be changed accordingly.For the details of male and female head connector,please get on internet for consuls.

SD card design

 

principle

for users'design of SD card,please follow strictly schematic to arrange IO dropdown,excessive dropdown will enable SD card not to work normally。reference diagram as below

Myzr dibansheji 3.1.0.1.png

  note:if users don't need SD card,but need TF card,since TF card doesn't have function of write-protect.Write-protect signal(SD3_RST/SD3_WP)need to pull down,which can't be hanged directly in the air.If TF card booth is designed with hot swap,must make clear which pin of TF card is for dectection. normally when insert the card,detection pin will be grounded,the inserted detection pin KEY_COL/SD3_CD_B)need to pull up.If TF card booth is designed with flip type,write-protect need to pull up,at the same time the inserted detection signal need to be grounded(just as a card is kept in the booth)
  if need additional ESD protect,please ensure a small capacity value on SD_CLK signal。

 

PCB

SD0,SD1,SD2,SD3,CMD,CLK signal need an equal treatment。ESD originals need to be very close to SD card booth。

SATA design

 

principle

 SATA principle is simple by contrast, only need to ensure a correct direction. since current on SATA is normally a little big, 5V current inputted is better not to be as low as 3A。
Myzr dibansheji 4.1.0.1.png

PCB

the four capacitors which are seriated to SATA signal should be close to SATA booth。
100 ohm difference resistance matching up
length tolerance for each group of differences pairs is controlled within ±5mil
require a full reference to ground level

HDMI

 

principle
HDMI stand can't be linked with wrong definition


Myzr dibansheji 5.1.0.1.png

PCB

100 ohm difference resistance matching up。
length tolerance for each group of differences pairs is controlled within±5mil
require a full reference to ground level
protect component CM2020 can't be ignored。

 

LVDS

 

principle

if transmitting distance for LVDS signal is long,and screen linked with is bigmagnetic coupling can be put in serial on LVDS signal for a better transmiting quality。

PCB

100 ohm difference resistance matching up。
length tolerance for each group of differences pairs is controlled within±5mil
if two way LVDS signal is used for 1080p display,。LVDS0 and LVDS1 signal need an equal treatment。
require a full reference to ground level

RGB port LCD

 

principle

LCD as RGB port need to be matched up with interface model with 24bit,18bit

CPU signal(note1)

24bit(note2)

18bit(note3)

18bit(note4)

D0

B0

 

B0

D1

B1

 

B1

D2

B2

B0

B2

D3

B3

B1

B3

D4

B4

B2

B4

D5

B5

B3

B5

D6

B6

B4

G0

D7

B7

B5

G1

D8

G0

 

G2

D9

G1

 

G3

D10

G2

G0

G4

D11

G3

G1

G5

D12

G4

G2

R0

D13

G5

G3

R1

D14

G6

G4

R2

D15

G7

G5

R3

D16

R0

 

R4

D17

R1

 

R5

D18

R2

R0

 

D19

R3

R1

 

D20

R4

R2

 

D21

R5

R3

 

D22

R6

R4

 

D23

R7

R5

 


note1.
  D0 indicate a minimal level for CPU liquid crystal port,
  D23 indicate a maximal level for CPU liquid crystal port
note2
  B0-24 bit blue bit of liquid crystal at minimal level,
  B7-24 bit blue bit of liquid crystal at maximal level,
  G0-24 bit green bit of liquid crystal at minimal level,
  G7-24 bit green bit of liquid crystal at maximal level
  R0-24 bit red bit of liquid crystal at minimal level,
  R7-24 bit red bit of liquid crystal at maximal level
note3.
   in use of this kind of link,LCD software still choose 24bit model
  B0-18 bit blue bit of liquid crystal at minimal level,
  B5-18 bit blue bit of liquid crystal at maximal level
  G0-18 bit green bit of liquid crystal at minimal level,
  G5-18 bit green bit of liquid crystal at maximal level
  R0-18 bit red bit of liquid crystal at minimal level,
  R5-18 bit red bit of liquid crystal at maximal level
note 4.
  if in use of this link method,LCD software need to choose 18bit model
  B0-18 bit blue bit of liquid crystal at minimal level,
  B5-18 bit blue bit of liquid crystal at maximal level
  G0-18 bit green bit of liquid crystal at minimal level,
  G5-18 bit green bit of liquid crystal at maximal level
  R0-18 bit red bit of liquid crystal at minimal level,
  R5-18 bit red bit of liquid crystal at maximal level


if there is a strict request with static,need ESD protect for LCD signal。

PCB

for all data lines,need an equal treatment for CLK signal
request a full reference to ground level

 

CMOS

 

Myzr dibansheji 8.1.0.1.png

principle

 

PCB

since frequency of MCLK and PIXCLK signal is very high,need isolation treatment when Layout
data,need an equal treatment for clk signal。
request a full reference to ground level

USB

 

principle

USBHOST expanded with 4 and USBHOST via LAN9514,and expanded with one way 10M/100M ethernet interface。
a coupling inductance is put in serial on USB line。


Core board USB_H1_VBUS signal of core board need to be connected with 5V power supply through magnetic bead。
if power supply Host out of the board,please include over-current protect component for USD。

Myzr dibansheji 8.3.0.1.png

so far only device port can be done in layout of hardware for MINIUSB port,if need function of HOST,please refer to OTG layout from FSL official。

PCB

90 ohm difference resistance matching up
request a full reference to ground level
current to supply outside need to be big enough。

 

CAN

 

principle

since CAN的TX,RX signal is 3.3V electrical level,attention to conversion of electrical level。
Myzr dibansheji 9.1.0.1.png

PCB

CANH,CANL check signal。

 

PCIE

 

principle

TX,RX signal need to connect in serial with 0.1uF capacitor(if an external module is already with a capacitor in serial,then no need to connect a capacitor again)
CLK signal connect in serial with 0.1uF capacitor,at the same time put a 49.8 resistor to ground in parallel with another end of the capacitor 。
Myzr dibansheji 10.1.0.1.png

PCB

85 ohm difference resistance matching up
request a full reference to ground level

 If you would like to know more about our products, please visit www.myzr-tech.com or email to enquiry@myzr.com.cn.

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