Use notes of Lichuang EDA

Lichuang EDA

In Lichuang EDA Made on PCB You can import directly to jialichuang to place an order , Each registered user can place two free orders every month , Limit PCB Size 10CMx10CM, Five pieces per order , Even production to express all free , It is very suitable for making samples .

Lichuang website https://lceda.cn/,

SCH line

There is nothing to say about the circuit diagram , Make PCB The first important but easy step . Several points needing attention in the process

• Select the components of the appropriate pad
  1. General components are relatively simple , It depends on the pad size , 0805, 0603 perhaps 0402, Hand welded board to 0603 Just fine , 0402 Welding is more difficult , Because the components are too small , It is easy to be blown away or statically adsorbed by other objects .
  2. Power devices , LDO these , SOT89, SOT223, SOT23, Pay attention to the distinction , The size varies greatly , Avoid putting PCB It's inappropriate to come back and rework
  3. The layout of connecting devices is more diverse , One USB Type-B There are more than a dozen layouts , Remember the most commonly used , Otherwise PCB When I came back and found that the spare parts were inappropriate, I had to buy another one .
• stay PCB Under the area limitation , Try to choose the most versatile and easy to weld devices , For example, it is designed to 0805 The pad of the , Convenient welding , No, 0805 In the case of 0603 Can also paste .
• The order of needle arrangement function should refer to the design of similar common products , If there is a general order, use the general order , The daily habit of wiring is not easy to change , Unification can reduce the risk of errors .
• In order to make the circuit diagram more concise ( Avoid winding ), Most circuits will use Net Label Formal annotation , At this time, pay attention to distinguish
• Just connect , If the intersection is connected, there will be a dot

Shortcut key

• Move the canvas : Right click and drag
• Zoom in and out : Mouse wheel
• Rotating element : Click and then click the blank , or R
• attachment : W, Press Esc sign out

PCB

Edit according to the layer

1. Similar to other drawing software . When switching to pads or components existing in the current layer , Will highlight , Others darken .
2. The more important thing is the front , Back ( double PCB), Outer frame These three floors
3. After selecting a layer , Press Shift+S You can hide other layers , It is convenient to modify on the current layer
4. Press K You can immediately adjust the size to adaptive

Company

Click... In the blank space without components , Units can be selected in the right attribute bar , mm, mil, 100mil=2.54mm

PCB Board size

Switch to the outer frame layer

• In this layer , Just draw lines in the normal way , PCB During production, it will make plates according to this size
• Click twice on the side , You can select this edge individually , Modify the position through attributes

put

Press space or R, Can rotate components

wiring

After the components are placed and fixed , Click the wiring icon , Or press the shortcut key W Wiring

Basic operation

• Wiring angle : Oblique line 45°, Go at an obtuse angle , Do not have right angles or acute angles
• Wiring width : Before the connection ends , Press Tab Key can modify the width . The minimum use of signal line 6mil, It's usually 10mil, Power cord recommendations 15mil above
• Error message : If wiring violates the default rules , There will be X Tips , Need modification
• modify :
  • Click to select the line , Point in the center line of the point , Will only move this point ( The points on both sides don't move , Adjust the angle and length )
  • Click to select the line , Press and hold the line , Will move the middle edge with two points ( Keep the angle , Adjusting position )
  • Click to select the line , Three strikes hit the middle of the line , You can add a little
  • Point in the line , Three clicks can delete
• GND: No wiring , Leave the last copper
• Cloth thread , Will take it net identification , Zoom in to a certain multiple to see , At this time, the benefits of high-resolution display are shown
• from SCH to update PCB when , Wired net Not necessarily updated , If you still keep the original net identification , There will be ratline

Through hole

• When the connection is blocked , It can be connected through a through hole .
• First draw a line through the hole , Then point a via on the line , Then cloth the other side
• After wiring , You can add a through hole in the copper area , Strengthen ground wire connectivity ( Avoid capacitive effects )

Fly line ratline

• Flywires are used to indicate the connectivity between pads
• After wiring connection , The flying line between the two pads will disappear
• After all connections are completed ( Including copper coating ), The straight lines between the pads should all disappear , If there is still , It means that this part has not been wired
• You can select from the object type in the tool box , Display only ratline Check all flying lines , Convenient for inspection

moisturize Teardrop

• After all connections are completed , It can be used TearDrop Moisten the wiring between the wiring and the pad to avoid right angles
• If copper has been applied , Copper coating will be automatically adjusted after wetting
• Teardrop Also bring net identification , But it is often covered by components and cannot be found intuitively , If you want to modify the wiring , It is recommended to hide components first , Then put the... On the pad to be changed Teardrop First delete

Copper coating

• Select the layer , Click the dotted copper coating button in the tool set , Then select the box PCB peripheral , After the box ( You can see the dotted line changes ), Then press Esc, Copper will be applied to the selected area in this layer .
• The double-layer board needs to be coated with copper on both sides
• In global settings , Set the copper coating invisible ( Show only borders ), It is recommended to hide the copper coating when modifying the wiring
• Click the dotted box with copper , You can adjust the connection mode of copper coating on this side and bonding pad , Divergent or direct connection , Direct connection will not leave a gap
• After circuit modification , Re moisten (Teardrop), It will automatically reapply copper , You can also click the button to reapply copper

Silk screen

Click on T Tools , You can add text

Delete component ID in batch

The identification of components has several parts : Component name , Component number , And the silk screen of the pad outline . The first two can be hidden in the settings , Will not appear in the final PCB Yes .

Right click on the component , Select a similar type , In the attribute box on the right , Set the identification and number to not display , It's all hidden ( There will be no silk screen printing when making )

3D preview

Generate 3D preview , intuitive , You can see the spacing between components , Whether the arrangement is too dense , Is there any overlap , Check whether the silk screen printing is correct, etc . Some low-level mistakes can be avoided .

modify

• When modifying , If the wiring diagram changes , First from SCHEMATICS Change , And then again Update To PCB
• Wiring and vias , Including the edges produced by wetting , All have Net Name , Modify the line , For example, after switching the order of needle arrangement , Of these components Net label Maybe it's wrong , Need modification , Otherwise, errors will be displayed or generated ratline
• moisturize (TearDrop) The resulting edge may not be easy to spot under the pad , You can hide components , Replace these small components Net Label. Or in TearDrop Set delete... In the dialog box , Do it uniformly after the modification TearDrop
• Last in ratlines( Fly line ) On the floor Shift+S Hide other layers , See if there are any untreated flying lines

Video learning : https://www.bilibili.com/video/BV1dU4y187fN

Work recommendation

STM32 Development board series

• https://oshwhub.com/spadger/bluepill
  Spadger Of STM32F103C8T6 Core board , MicroUSB, LDO It uses a less common SE8533
• STM32F103C8T6 Core board https://oshwhub.com/baobaoa/bluepill
  Baobaoa stay Spadger Based on the modified version of the project , USB Change it to Type-C, LDO Change it to SOT89 Of AMS1117