Test ESP8266 AT commandos

esp8266-03-result.md

Connected to my ESP8266-ESP-03 with following baudrate settings

BAUD = 9600
BOOT_BAUD = 115200

esp8266_at_test.py prints this:

PINGING esp8266...
> AT
> 
> OK

RESETTING esp8266...
> AT+RST
> 
> OK
> 
>  ets Jan  8 2013,rst cause:4, boot mode:(3,7)
> 
> wdt reset
> load 0x40100000, len 612, room 16 
> tail 4
> chksum 0x12
> load 0x3ffe8000, len 788, room 4 
> tail 0
> chksum 0x50
> load 0x3ffe8314, len 264, room 8 
> tail 0
> chksum 0x4a
> csum 0x4a
> 
> 2nd boot version : 1.1
>   SPI Speed      : 40MHz
>   SPI Mode       : QIO
>   SPI Flash Size : 4Mbit
> jump to run user1
> 
> sd

ASKING FOR MODE...
> AT+CWMODE?
> +CWMODE:3
> 
> OK

esp8266_at_test.py

#!/usr/bin/python3

"""ESP8266 serial port communication test / notes"""

from serial import Serial
from time import sleep
import codecs

# Serial port device where the ESP8266 is connected
PORT = "/dev/ttyUSB1"

# From http://www.esp8266.com/wiki/doku.php?id=getting-started-with-the-esp8266
# First, your board might talk at any of several baud rates. The ones to try
# first are 9600 and 115200. Then 57600 and/or 76800 (38400 * 2). Note the noise
# when you reset the device (pull the RST pin to ground) is typically some bootup
# messages at 76800. But there should be a ”ready“ message at the selected baud
# rate if your UART Rx is wired correctly. 
BAUD = 9600
BOOT_BAUD = 115200


def send(port, data):
    """Write data to the given serial port. `data` will be interpreted as an
    utf-8 string and encoded as a bytes array, terminated with '\\r\\n'.
    This blocks until all data has been send.
    """
    n = port.write(data.encode("utf-8")+b"\r\n")
    port.flush()
    return n


def receive(port, pause=0.1):
    """Wait a bit and receive data from `port`."""
    sleep(pause)
    x = port.in_waiting
    res = b""
    while x:
      res += port.read(x)
      sleep(pause)
      x = port.in_waiting
    return res


def errorbytes2hexstr(e):
    """Handler for UnicodeDecodeError convert bytes to python style string of
    hex numbers (every number representing one byte prefixed with '\\x'.
    """
    data = e.object[e.start:e.end]
    res = ""
    for b in data:
        res += "\\x" + "{:02x}".format(b).upper()

    return (res, e.end)


codecs.register_error('errorbytes2hexstr', errorbytes2hexstr)

def printlines(data):
    string = data.decode('ascii', 'errorbytes2hexstr')
    for line in string.splitlines():
        print("> {}".format(line))


if __name__ == "__main__":

    port = Serial(port=PORT, baudrate=BAUD)
    port.reset_output_buffer()
    
    print("PINGING esp8266...")
    send(port, "AT") # pinging esp8266
    printlines(receive(port))

    print("\nRESETTING esp8266...")
    send(port, "AT+RST") # reset esp8266
    printlines(receive(port, pause=0.03))
    port.baudrate = BOOT_BAUD
    sleep(2)               # esp8266 needs some time for booting
    printlines(receive(port))
    port.baudrate = BAUD
    
    print("\nASKING FOR MODE...")
    send(port, "AT+CWMODE?"); # query esp8266's mode
    printlines(receive(port))

    port.close()