HUZZAH ESP8266 Serial

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tgates
 
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HUZZAH ESP8266 Serial

Post by tgates »

Hello,

I recently bought a HUZZAH ESP8266 board here from Adafruit and have been trying to get a response from it by following the tutorial.

I am connecting to a simple inexpensive USB-serial adapter that I already had (Ground to pin 5, TX/RX on pins 2/3) but I only seem to get garbage in my terminal emulator.

When I send power to the unit alone (5V from a wall-wart power supply off a USB breakout) the red and blue lights blink for a moment as seems to be expected, but no matter what baud-rate and terminal program I try, I only get garbage to the console once I connect it up to my computer. The red light stays on, and pressing keys makes the blue light blink, but I only receive back seemingly random characters (at 9600 carriage return sends back a "C" character, for instance). I've tried every baud rate, parity setting, bit setting, but the results seem to be similar.

Did I brick it by connecting 232 without a level shifter? I know my USB-232 adapter works, and I've also tried it with my old dell laptop with a real 232 port with the same outcome. I don't know what else to try. After playing around with it for a while now it doesn't even seem to boot at all if the serial is connected to either of my computers..

Suggestions?

Thank you.

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adafruit_support_rick
 
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Re: HUZZAH ESP8266 Serial

Post by adafruit_support_rick »

Does your adapter have TTL levels (5V) or RS232 levels (+- 12V)? If it is an RS232 adapter, you've probably fried your ESP8266.
Same goes for connecting it directly to a serial port on your computer. That will have RS232 voltage levels, which will damage your ESP8266

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tgates
 
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Re: HUZZAH ESP8266 Serial

Post by tgates »

I sort of suspected so.

I guess I'll get a proper TTL cable and replace my board.

I am curious though, the spec on the Hazzah ESP8266 product page lists "Level shifting on the UART and reset pin", what voltages then is that limited to? Or did this mean for different pins?

Thanks.

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Re: HUZZAH ESP8266 Serial

Post by adafruit_support_rick »

The ESP8266 is a 3.3V device. It has level shifting on the UART and reset to tolerate 5V levels.

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tgates
 
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Re: HUZZAH ESP8266 Serial

Post by tgates »

Works fine with the 3.3V TTL USB interface. The unit was not damaged.

I guess I just misunderstood and thought the level shifting meant I could use an RS232 interface.

Thank you for the support!
Last edited by tgates on Wed Sep 02, 2015 5:23 pm, edited 1 time in total.

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Re: HUZZAH ESP8266 Serial

Post by adafruit_support_rick »

Excellent! Glad it's not toasted!

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