Problem with CH340G

[AmySakura]

I've bought a CH340G USB to TTL converter and then connected to ESP8266.  Then plugged the USB end into my laptop (Windows 8 64-bit).
However, there was no sign of serial port in my Device Manager.  The blue and red led lights on the CH340G did light up though.

Then I tested with Arduino UNO, and yes, the serial port showed up in the Device Manager.
So, all the USB slots in laptop function just fine.

I've also installed the CH340 driver from here: http://www.wch.cn/download/CH341SER_EXE.html , but still didn't work.  I suppose it's because the Device Manager didn't detect it?

Down below are the pictures of the situation of CH340G and how I connected it with ESP8266.

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[ballscrewbob]

Double check that the VCC is indeed 3.3 volts as many of those will output 5 volts that in most cases that will fry an ESP 01 series.

Not always an issue but make sure you are using USB 2.0 ports too.

[DrAzzy]

Disconnect the ESP8266, see if it detects.

If not, assume bad hardware and buy another - $1.50 serial adapters have a non-zero DOA rate.

[mrbilky]

I had to flash the board http://www.nodemcu.com

[AmySakura]

Thank you guys.
Well, it seems to be that the supply current wasn't enough. Trying to fix that.
I think my USB port is 2.0? I'm not sure.
And the esp8266 is connected to 3.3V.

[AmySakura]

Check it again, found out the USB port in my laptop is USB 3.0
Will this affect the result?

I re-connected ESP8266 and CH340 with Arduino Uno (as power supplier).  The little red LED on ESP8266 turned on, but the Device Manager still couldn't get CH340's port.
I'm thinking connecting esp8266 with USB-TTL converter with a voltage regulator.

[AmySakura]

Disconnect the ESP8266, see if it detects.

If not, assume bad hardware and buy another - $1.50 serial adapters have a non-zero DOA rate.

Not sure what you meant. 
Do you mean testing CH340G only without ESP8266, Arduino and other stuff?

[DrAzzy]

Yes, test it with just the CH340G and see if it detects. If it does, then you know the USB serial adapter is fine, and that implies that the problem when the ESP8266 is connected is due to the load from the esp8266. If it doesn't, you declare the serial adapter dead and buy a new one. I buy those things 5-at-a-time.

Uh - you are using a 3.3v serial adapter, right, not a 5v one? The esp8266 is a 3.3v device and is not 5v tolerant. Most 3.3v serial adapters are not able to supply enough current to power an esp8266, so you will probably need an external voltage regulator to get 3.3v for the ESP8266.

Which version of serial adapter is it? (link to listing or post pic) I like the ones that look like this one (no specific endorsement of this listing) https://www.ebay.com/itm/USB2-0-6Pin-CH340G-Converter-for-STC-Arduino-PRO-Instead-of-CP2102-PL2303-To-TTL/191146797242 - with the little switch for voltage. But that still won't power an ESP2866 at 3.3v, it's just the nicest of the el-cheapo serial adapters.

[AmySakura]

Yes, test it with just the CH340G and see if it detects. If it does, then you know the USB serial adapter is fine, and that implies that the problem when the ESP8266 is connected is due to the load from the esp8266. If it doesn't, you declare the serial adapter dead and buy a new one. I buy those things 5-at-a-time.

Uh - you are using a 3.3v serial adapter, right, not a 5v one? The esp8266 is a 3.3v device and is not 5v tolerant. Most 3.3v serial adapters are not able to supply enough current to power an esp8266, so you will probably need an external voltage regulator to get 3.3v for the ESP8266.

Which version of serial adapter is it? (link to listing or post pic) I like the ones that look like this one (no specific endorsement of this listing) https://www.ebay.com/itm/USB2-0-6Pin-CH340G-Converter-for-STC-Arduino-PRO-Instead-of-CP2102-PL2303-To-TTL/191146797242 - with the little switch for voltage. But that still won't power an ESP2866 at 3.3v, it's just the nicest of the el-cheapo serial adapters.

Thanks.
I tested it out and the CH340G IS DEAD! ...No wonder.  I guess I just have to buy a new one.
The serial adaptor I use is this one. It's a chinese website though.
https://tw.bid.yahoo.com/item/%E3%80%90UCI%E9%9B%BB%E5%AD%90%E3%80%91-11-10-CH340G%E6%A8%A1%E5%A1%8A-USB%E8%BD%89TTL-%E5%8D%87%E7%B4%9A%E5%B0%8F%E6%9D%BF-STC-100377309133

[DrAzzy]

Those adapters, in particular, have a fairly high failure rate. On the ones I've had, build quality was horrifyingly bad (among other things, the USB connector housing usually wasn't soldered down, leaving it vulnerable to fatigue damage to the solder joints on the usb connector from plugging+unplugging it). They also don't break out DTR so you can't use them to easily program an Arduino Pro Mini or similar if you ever get one of those.

I would be sure to get a better model for your replacements (get ones that look like what I linked above, the black ones with the switch - they should be like $1.50-$2 shipped from ebay/aliexpress/etc).