Hi,
I'm new to PCB desinging and I'm using KiCad. I have created a schematic using ESP32 S3 waroom-1, TM1367, 8 header pins connecter to connect ESP with RDIF RC522 reader. Can you look at the full schematic and advice me on it. I ran a ERC it did not show any error.
I moved your topic to a more appropriate forum category @dheenadayalann.
The Nano Family > Nano ESP32 category you chose is only used for discussions directly related to the Arduino Nano ESP32 board.
In the future, when creating a topic please take the time to pick the forum category that best suits the subject of your question. There is an "About the _____ category" topic at the top of each category that explains its purpose.
Thanks in advance for your cooperation.
Ok got it, thanks
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It's very hard to trace the connections between the separated circuit parts. A PCB designer should allow for a symbolic circuit diagram as well, without separated circuit parts.
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There is a whole plethora of wires connecting the 3V3 line to ground.
When using a low drop out regulator (LDR), like you have, the capacitave loading is important. It could be that there is too much capacatance to start the LDR. Check your data sheet for this part.
Also check the TM1637 data sheet to see if it can supply enough current at 3V3 to actually light the seven segment display. There seems to be no current limiting resistors anywhere on the circuit for the seven segment display.
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The thing that bothers me the most is the lack of decoupling capacitors in the 100nF range. I agree with @DrDiettrich on the schematic structure. Overall it looks good.
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Have you breadboarded it yet? Do you know if it works if the schematic matches your breadboard?
You are powering your TM1637 with 3.3v, that is within the working range of the TM1637, however the TM1637's typical voltage is 5V.
The LTC-4627j site is down so I can't look at it's data sheet but do you know if the drive from the TM1637 at 3.3v is enough to light the LTC-4627j?
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Ok got it, It is my first schematic i will surely make these changes. Thanks a lot.
Thanks i will check it
Thanks I will take a look
Yes I have but I test it with the TM1367 module it worked fine with 3.3v . I will look at the data sheet now
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the link stated the input voltage is 3.7 to 5.3V. It is common for devices to work beyond the stated specifications, are the digits bright enough? You would not be happy if you found after you made and built the board that at a little temperature change (warm or cold) causes it not to work.
No, So do i need to power it with 5V then?
I can't say, you said you breadboarded the circuit and it worked at 3.3v. Were the digits bright enough for you? If you were to power the display with 5v, the ESP needs 3.3V so you would have to address the voltage difference. The only way I have been able to have the I2C work reliably from 3.3v to 5v is to use a TXS0108 level shifter IC. The "level shifters" on ebay that use a Mosfet will not work on I2C because they react too slowly.
Also look at the I2C connections. you have 10K in series, usually the 10K is a pullup to V+.
Yes , will chcek it
Hi, @dheenadayalann
Welcome to the forum.
Your diagram is a PCB map, well layed out, but not a schematic.
A schematic shows connected annotated points with wires, to enable a simple a easy circuit analysis.
Supply and gnd connections can be netted, but signals need wires.
For example, if I need to trace D1 and D2 from the USB port, I could have to look at ALL the net names to find the other and if there is more than a pair.
A schematic would show a connecting wire and how many points are connected instantly.
Sorry but following a PCB CAD design is a "search a word" puzzle.
Practice.. practice practice.. 
Tom.... 
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Thanks for your advice will work on it
Hi,
Take a look at this diagram for reference only.
Please note that:
- Some conenctions and components are missing
- Final connections and component value may vary.
ESP32.pdf (33,8 KB)
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For I2C 3V3 yp 5V many times I pull it up with ~3K to the +3V3 based on this, and it does work:
This is from: Requirements For Devices - I2C Bus
Requirements For Devices
The I2C specification poses several requirements to I2C devices in order to ensure proper operation in different environments. The most important ones are:
• Both, SDA and SCL, must be open drain and must not be driven high by any device attached to the I2C bus.
• In most I2C buses, the low and high input voltage level thresholds of SDA and SCL must depend on Vcc. E.g. an SDA voltage level of 1.1 V will be interpreted as low in an I2C bus with Vcc = 5 V and as high in an I2C bus with Vcc = 1.2 V.
• The SCL and SDA signals must be sampled by Schmitt Trigger inputs, i.e. with a certain hysteresis.
• Spikes in SCL and SDA signals must be filtered up to a certain amount (only for full speed I2C).
• Setup and hold times; this includes a specified maximum SCL clock rate (100 kHz for normal speed, 400 kHz for full speed).
Most off-the-shelf standard I2C ICs fulfill these requirements while e.g. I2C software implementations in microcontrollers often do not. This does not necessarily need to be a problem as long as the environment does not require a feature that one of the devices on the I2C bus does not support, but has to be kept in mind when tracking down I2C bus-related problems.
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Hardware requirements can not normally be fulfilled by software, like open drain outputs.
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