[GreenKeys] ESP8266 WiFi Module UART

[Simon Claessen]

On 28-12-15 17:05, Jeffrey D Angus wrote:
> On 12/28/2015 7:39 AM, simon wrote:
>>
>>
>> On 26-12-15 15:51, Jeffrey D Angus wrote:
>>
>>> I notice this one seems to use the I^2C serial data buss. That's not
>>> the same as RS-232 serial data.
>>> It also runs off of 3.3 vdc and will HCF (Halt and Catch Fire) on 5
>>> vdc.
>> I'm unable to locate the data supporting that statement. could you
>> send us a link?
> As I posted previously:
>>> just stumbled across this on eBay.
>>> <http://www.ebay.com/itm/141454423509>
>>> With shipping, $5.59.
>>> Here's the data sheet:
>>> <https://nurdspace.nl/ESP8266#Translated_datasheet>
>>> More documentation:
>>> <http://www.electrodragon.com/w/index.php?title=Category:ESP8266&redirect=no>
>>>
>>> And some app notes:
>>> <https://www.zybuluo.com/kfihihc/note/31135>
>  From the translated data sheet for this specific product:
> Main Serial Interface (SI) can run at two, three, four-wire bus
> configuration, is used to control the
> EEPROM or other I2C / SPI devices.
>
> --

Ah, the translated datasheet. thanks.

I know the guys from nurdspace. they are a nice bunch.
the specs you are talking about are not about the uart but the serial 
interface. as they wrote there, it is used to talk to the flash chip 
where your code resides. the uart is a separate thing. and there is even 
a second uart on the ESP-201 but one pin is in use for the flash chip. I 
have not yet found out if that pin can be freed to be able to have a 
functional second uart.

3.3 volt should not be a problem, as a 3.3v high is high enough to 
thigger a high in a 5volt setup and for example, a uln2003 can easily be 
driven by a 3.3v micro.. a divider or mosfet as level converter the 
other way is workable up to 57600 or sometimes even 115200. As our 
beloved machines can only dream of using such speeds, a resistor divider 
is more than adequate.

I stongly advise to buy the bigger esp-201 as it has more free pins than 
the very cheap esp-01 as two pins are needed to upload a program to the 
chip.

an usb-ttl converter running on 3.3v is mandatory. some can be rewired, 
but the molded in plastic ones are fixed. I prefer the real ftdi ones 
from sparkfun or adafruit over the counterfeit chinese ones as the 
latter are behaving strange in some circumstances with the ftdi driver

the real fun with the esp is that it can run a small webserver as well. 
with altering just a few lines of html in a arduino sketch you can turn 
things on or of with your tablet, smartphone or desktop computer. And it 
can be configured as hotspot or regular client, so dive into the arduino 
development enviroment to get up and running in no time. Of course if 
you are a seasoned user of annother programming language or IDE, ignore 
the previous suggestion. the should be a library for the esp in your 
language (although cobol, algol and fortran might be out of scope here)

simon
-- 
Met vriendelijke Groet,

Simon Claessen
drukknop.nl