I am trying to design a schematic of Esp32 thourgh chip CH340C. I'm a bit concerned Is there any isssues. Please help me

 

Welcome to AAC!

D6 is the wrong way round. As drawn it shorts the VBUS to ground.

Not sure why you need R12.

R12 and others - 4k75 is unusual value, did you mean 4k7?

IO17 (Switch) doesn't seem to go anywhere? I'm guessing to SW1 off board somewhere? You'll need to tag it with a label to pass ERC validation checks (in KiCAD?). Also tag power lines with a POWER_FLAG for same reason.

SW3 - you probably don't need C12 0.1u as you have C7 1u on the EN line anyway.

Can't see anything else concerning at the moment...

Other than SW1 and SW4 and the light sensor, you've replicated an ESP32 mini dev board. You could get one of those and an Adafruit BH1750 light module and marry them for arguably less money/hassle and a lower risk development cycle.

 

if you are designing PCB, it cannot hurt to bring few IOs and 3V3/GND to a connector. it does not have to be populated but it can be great for any additions that may come up pater on.

 

Welcome to AAC!

D6 is the wrong way round. As drawn it shorts the VBUS to ground.

Not sure why you need R12.

R12 and others - 4k75 is unusual value, did you mean 4k7?

IO17 (Switch) doesn't seem to go anywhere? I'm guessing to SW1 off board somewhere? You'll need to tag it with a label to pass ERC validation checks (in KiCAD?). Also tag power lines with a POWER_FLAG for same reason.

SW3 - you probably don't need C12 0.1u as you have C7 1u on the EN line anyway.

Can't see anything else concerning at the moment...

Other than SW1 and SW4 and the light sensor, you've replicated an ESP32 mini dev board. You could get one of those and an Adafruit BH1750 light module and marry them for arguably less money/hassle and a lower risk development cycle.

OMG thanks sir, its my mini project to improve knowledge so I need to clone esp32 module. Thanks for detailed explanation and considering. Best wishes for you

 

Welcome to AAC!

D6 is the wrong way round. As drawn it shorts the VBUS to ground.

Not sure why you need R12.

R12 and others - 4k75 is unusual value, did you mean 4k7?

IO17 (Switch) doesn't seem to go anywhere? I'm guessing to SW1 off board somewhere? You'll need to tag it with a label to pass ERC validation checks (in KiCAD?). Also tag power lines with a POWER_FLAG for same reason.

SW3 - you probably don't need C12 0.1u as you have C7 1u on the EN line anyway.

Can't see anything else concerning at the moment...

Other than SW1 and SW4 and the light sensor, you've replicated an ESP32 mini dev board. You could get one of those and an Adafruit BH1750 light module and marry them for arguably less money/hassle and a lower risk development cycle.

Beside can I ask a small question. Can I remove the Bidirectional TVS Diode in the wire connect D+ with DP2, DP1 cause I can buy them or find the similar one. Thanks

 

the TVS are there only for protection (always a good idea in robust design) but circuit can work without them. they are low cost items and easily found, and since you can buy them, not sure why wouldn't you. the other way to add protection is to use pair of clamping diodes connected to supply (5V and GND).

 

the TVS are there only for protection (always a good idea in robust design) but circuit can work without them. they are low cost items and easily found, and since you can buy them, not sure why wouldn't you. the other way to add protection is to use pair of clamping diodes connected to supply (5V and GND).

thanks sir but It’s really hard to find bidirectional TVS diodes with low capacitance for D+ and D- . How can i solve that

 

thanks sir but It’s really hard to find bidirectional TVS diodes with low capacitance for D+ and D- . How can i solve that

Ask the right question?

Go to mouser.com (or your local version)
Search TVS Diodes
In the filter section choose capacitance<0.25pF (or whatever value you prefer)
also pick ranges for clampdown voltage, channel count, etc as appropriate
click 'apply filters'



Some useful info re products, layout, etc.

https://next.gr/tutorials/diodes-and-rectifiers/using-tvs-diode-for-usb-protection-tutorial useful tutorial
https://www.ti.com/lit/an/slvaf82b/slvaf82b.pdf TI's tutorial and recommended products
https://www.littelfuse.com/assetdocs/littelfuse-esd-and-port-protection-design-guide
https://fscdn.rohm.com/en/products/databook/applinote/discrete/diodes/selection_method_and_usage_of_tvs_diodes_an-e.pdf ROHM's guidelines
https://www.murata.com/en-eu/products/emc/esd/overview/basic/use-case/external-io-interfaces Murata's guidelines and product

 

it does not need to be bidirectional. unidirectional can work too if K is on signal and A is on GND. i see no shortage of TVS of either type, both in THT and SMD so maybe the challenge is regional (war, sanctions, natural disasters, people on strike, whatever...).
then i am looking for parts, i try parametric search on popular distributors like Mouser,DigiKey,Newark etc. or aggregators like Octopart.com

also there are AIs and some of suggestions are:

for USB2:

• Semtech: $\mu$Clamp0571P, $\mu$Clamp0582B, RClamp7522T, RClamp0504N
• Littelfuse: SP3021-01ETG, SP3022-01ETG
• Onsemi: ESD9B5.0ST5G, ESD5Z5.0T1G
• Diodes Inc: D5V0F1U2LP-7B, DESD5V0U1BA-7

USB-C & high speed:

• Semtech: RClamp03391PW, RClamp3371ZC, $\mu$Clamp2411ZA (for CC/SBU pins), TDS2221PW (for VBus)
• TDK: B74111U0033M060, B74121U0033M060, B74121G0200M060
• Texas Instruments: TPD4E05U06, TPD1E01B04, TPD8S300/TPD6S300 (specifically for USB-C surge/overvoltage)

 

Ask the right question?

Go to mouser.com (or your local version)
Search TVS Diodes
In the filter section choose capacitance<0.25pF (or whatever value you prefer)
also pick ranges for clampdown voltage, channel count, etc as appropriate
click 'apply filters'

View attachment 364443

Some useful info re products, layout, etc.

https://next.gr/tutorials/diodes-and-rectifiers/using-tvs-diode-for-usb-protection-tutorial useful tutorial
https://www.ti.com/lit/an/slvaf82b/slvaf82b.pdf TI's tutorial and recommended products
https://www.littelfuse.com/assetdocs/littelfuse-esd-and-port-protection-design-guide
https://fscdn.rohm.com/en/products/databook/applinote/discrete/diodes/selection_method_and_usage_of_tvs_diodes_an-e.pdf ROHM's guidelines
https://www.murata.com/en-eu/products/emc/esd/overview/basic/use-case/external-io-interfaces Murata's guidelines and product

I seach every web that I can buy in my country but it still so hard to find the right one. By the way shouldn't TXD connect to other ends RXD? Have you tried reversing them if that's even possible. Im so confuse

 

By the way shouldn't TXD connect to other ends RXD?

Yes, I missed that! The TXD out from the CH340 goes to the RXD in on the ESP32 and vice versa as per the CH340 datasheet...



This is by convention... in a chain of devices the TXD goes to the RXD of the next one down in the chain and so on...

I seach every web that I can buy in my country but it still so hard to find the right one.

Where are you?

 

Yes, I missed that! The TXD out from the CH340 goes to the RXD in on the ESP32 and vice versa as per the CH340 datasheet...

View attachment 364445

This is by convention... in a chain of devices the TXD goes to the RXD of the next one down in the chain and so on...


Where are you?

Im from Vietnam, idk why but find it look like so hard, btw can u help fix that error message, I cant find solution after 2.5 hours

 

I search every web that I can buy in my country ...

well.... if you stated name of your country, others may be able to help.
you may also try pointing it on a map.

 

well.... if you stated name of your country, others may be able to help.
you may also try pointing it on a map.
View attachment 364450

i alr said it in the upper repply xD, btw help me solve the error message bro TT

 

missed that. There is DigiKey etc. in Vietnam.
you can also try clamping circuit:

i see no error messages. there are only three warning messages.
click on each to see where the problem is. i use KiCad and encounter same warning. this happens when pin on device expects to see that something else connected to it is a power source. if that is not the case, just attach PWR_FLAG. if complaint is that some wire is not connected, delete it.

 

missed that. There is DigiKey etc. in Vietnam.
you can also try clamping circuit:
View attachment 364451
i see no error messages. there are only three warning messages.
click on each to see where the problem is. i use KiCad and encounter same warning. this happens when pin on device expects to see that something else connected to it is a power source. if that is not the case, just attach PWR_FLAG. if complaint is that some wire is not connected, delete it.
View attachment 364453

Can i ignore warning message and jump into pcb design

 

missed that. There is DigiKey etc. in Vietnam.
you can also try clamping circuit:
View attachment 364451
i see no error messages. there are only three warning messages.
click on each to see where the problem is. i use KiCad and encounter same warning. this happens when pin on device expects to see that something else connected to it is a power source. if that is not the case, just attach PWR_FLAG. if complaint is that some wire is not connected, delete it.
View attachment 364453

Btw can i use bidirectional TVS diodes 35uF for this circurt to measure magnitude of dark/ light. its minimum IC that I can find

 

"ok","warning" and "error" are three severity levels in rule check. normally you can adjust that yourself - or choose to ignore them... but why not fix them?
i am not sure what you mean with TVS diode and 35uF. TVS diodes are supposed to have tiny capacitance (pF). adding value in tens of uF makes no sense or i am not understanding something.
"minimum microcontroller" is anything that can talk I2C. an arduino would do. even without real I2C, one should be able to bitbang it... but... why torture yourself?
even if you choose ESP32, why not get ready development board? they are low cost and ready to use. that is what i would do.