micropython esp8266

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<h1>MICROPYTHON ESP8266</h1>

<h2>Install</h2>

<p>Install esptool.<br>
<code>$ pip install esptool</code>

<p>Erase flash.<br>
<code>$ esptool.py --port /dev/ttyUSB0 erase_flash</code>

<p>Deploy firmware.<br>
<code>$ esptool.py --port /dev/ttyUSB0 --baud 115200 write_flash --flash_size=detect 0 esp8266-20170108-v1.8.7.bin</code><br>
(add -fm dio if needed)

<p>Connect USB-to-UART to board (GPIO1=Tx, GPIO3=Rx, baud=115200) and to computer.<br>
Connect computer wifi to Micropython-xxxxxx (password: micropythoN)

<p>Check firmware.<br>
<code>$ picocom /dev/ttyUSB0 -b115200
>>> import esp
>>> esp.check_fw()</code>

<h2>WebREPL</h2>

<p>Download WebREPL from https://github.com/webrepl

<p>Run this and follow the instructions.<br>
<code>>>> import webrepl_setup</code>

<p>Open WebREPL, connect to module (IP address 192.168.4.1), enter the WebREPL password.

<h2>Example</h2>

<code>>>> import machine
>>> pin = machine.Pin( 2, machine.Pin.OUT )
>>> pin.on()
>>> pin.off()
>>> def toggle(p):
...   p.value( not p.value() )
...
>>> import time
>>> while True:
...   toggle(pin)
...   time.sleep_ms( 500 )
...</code><br>
Ctrl+C to break

<h2>Filesystem</h2>

<p>Read/write file<br>
<code>>>> f = open( 'data.txt', 'w' )
>>> f.write( 'some data' )
9
>>> f.close()
>>> f = open( 'data.txt' )
>>> f.read()
'some data'
>>> f.close()</code>

<p>Directories<br>
<code>>>> import os
>>> os.listdir()
['boot.py', 'port_config.py', 'data.txt']
>>> os.mkdir( 'dir' )
>>> os.remove( 'data.txt' )</code>

<p>You can create boot.py and/or main.py files for start up script.

<h2>Networking</h2>

<p>Station and access point.<br>
<code>>>> import network
>>> sta_if = network.WLAN( network.STA_IF )
>>> ap_if = network.WLAN( network.AP_IF )
>>> sta_if.active()
False
>>> ap_if.active()
True
>>> ap_if.ifconfig()
('192.168.4.1', '255.255.255.0', '192.168.4.1', '8.8.8.8')</code><br>
It is IP address, netmask, gateway, and DNS.

<p>Enable station interface.<br>
<code>>>> sta_if.active(True)
>>> sta_if.connect( '<your ssid>', '<your password>' )
>>> sta_if.isconnected()
>>> sta_if.active( False )
>>> def do_connect():
...   import network
...   sta_if = network.WLAN( network.STA_IF )
...   if not sta_if.isconnected():
...     print( 'Connecting...' )
...     sta_if.active( True )
...     sta_if.connect( 'test', 'wifiwifi' )
...     while not sta_if.isconnected():
...       pass
...   print( 'ifconfig:', sta_if.ifconfig() )</code>

<h2>TCP Socket</h2>
<code>>>> import socket
>>> addr_info = socket.getaddrinfo( 'towel.blinkenlights.nl', 23 )
>>> addr = addr_info[0][-1]
>>> s = socket.socket()
>>> s.connect( addr )
>>> while True:
...   data = s.recv( 500 )
...   print( str( data, 'utf8' ), end = '' )</code>

<p>HTTP get.<br>
<code>>>> def http_get( url ):
...   _, _, host, path = url.split( '/', 3 )
...   addr = socket.getaddrinfo( host, 80 )[0][-1]
...   s = socket.socket()
...   s.connect( addr )
...   s.send( bytes( 'GET /%s HTTP/1.0\r\nHost: %s\r\n\r\n' % ( path, host ), 'utf8' ) )
...   while True:
...     data = s.recv( 100 )
...     if data:
...       print( str( data, 'utf8' ), end = '' )
...     else:
...       break
...   s.close()
>>> http_get( 'http://micropython.org/ks/test.html' )</code>

<p>HTTP server.<br>
<code>>>> import machine
>>> pins = [ machine.Pin( i, machine.Pin.IN ) for i in ( 0, 2, 4, 5, 12, 13, 14, 15 ) ]
>>> html = "&lt;!DOCTYPE HTML>&lt;html>&lt;body>&lt;h1>Pins&lt;/h1>%s&lt;/body>&lt;/html>"
>>> import socket
>>> addr = socket.getaddrinfo( '0.0.0.0', 80 )[0][-1]
>>> s = socket.socket()
>>> s.bind( addr )
>>> s.listen( 1 )
>>> print( 'listening on', addr )
>>> while True:
...   cl, addr = s.accept()
...   print( 'client connected from', addr )
...   cl_file = cl.makefile( 'rwb', 0 )
...   while True:
...     line = cl_file.readline()
...     if not line or line == b'\r\n':
...       break
...   rows = [ '&lt;p>pin %s is %d.' % ( str( p ), p.value() ) for p in pins ]
...   response = html % '\n'.join( rows )
...   cl.send( response )
...   cl.close()</code>

<h2>GPIO Pins</h2>

<p>Pins are 0, 2, 4, 5, 12, 13, 14, 15, and 16.<br>
<code>>>> pin = machine.Pin( 0, machine.Pin.IN, machine.Pin.PULL_UP )</code><br>
There is also machine.Pin.OUT.<br>
Use None to not use pull-up (default).<br>
GPIO 16 doesn't have pull-up.<br>
Use pin.on(), pin.off(), or pin.value(value) to set value.

<p>Interrupts<br>
<code>>>> def cb( p ):
...   print( 'pin changed', p )
>>> from machine import Pin
>>> p0 = Pin( 0, Pin.IN )
>>> p2 = Pin( 2, Pin.IN )
>>> p0.irq( trigger = Pin.IRQ_FALLING, handler = cb )
>>> p2.irq( trigger = Pin.IRQ_RISING | Pin.IRQ_FALLING, handler = cb )</code><br>
GPIO 16 cannot be configured to trigger a hard interrupt if its input changes.

<h2>Pulse Width Modulation</h2>
<p>Pins 0, 2, 4, 5, 12, 13, 14, 15 support PWM. They must be set at the same frequency.<br>
Frequency is between 1Hz and 1kHz.<br>
Duty is between 0 (fully off) and 1023 (fully on).<br>
<code>>>> import machine
>>> pwm = machine.PWM( machine.pin( 0 ) )
>>> pwm.freq( 500 )
>>> pwm.duty( 512 )
>>> pwm.freq()
500
>>> pwm.deinit()
Fade LED
>>> import time, math
>>> def pulse( pwm, t ):
...   for i in range( 20 ):
...     pwm.duty( int( math.sin( i / 10 * math.pi ) * 500 + 500 ) )
...     time.sleep_ms( t )
>>> for i in range( 10 ):
...   pulse( led, 20 )</code>
<p>Hobby motor servo use PWM frequency 50Hz and duty cycle between 40 and 115 so 77 is the center.

<h2>Analog to Digital</h2>

<p>There is only one ADC pin, value between 0 and 1024 (1.0V).<br>
<code>>>> import machine
>>> adc = machine.ADC(0)
>>> adc.read()
58</code>

<h2>Power Control</h2>

<p>You can double CPU speed.<br>
<code>>>> import machine
>>> machine.freq()
80000000
>>> machine.freq(160000000)</code>

<p>To deepsleep, connect GPIO16 to Reset pin.<br>
<code>>>> rtc = machine.RTC()
>>> rtc.irq( trigger = rtc.ALARM0, wake = machine.DEEPSLEEP )
>>> rtc.alarm( rtc.ALARM0, 10000 )
>>> machine.deepsleep()</code>

<p>On (boot) script you can detect the reset cause.<br>
<code>>>> if machine.reset_cause() == machine.DEEPSLEEP_RESET:
>>>   print( 'woke from deepsleep' )</code>

<h2>DS18S20 or DS18B20</h2>
<p>Temperature sensor, use 4k7 pull-up at data pin<br>
<code>>>> import time, machine, onewire, ds18x20
>>> ds = ds18x20.DS18X20( onewire.OneWire( machine.Pin( 12 ) ) )
>>> roms = ds.scan()
>>> ds.convert_temp()
>>> time.sleep_ms( 750 )
>>> for rom in roms:
...   print( ds.read_temp( rom ) )</code>

<h2>NeoPixel</h2>

<code>>>> import machine, neopixel
>>> np = neopixel.NeoPixel( machine.Pin( 4 ), 12 )
>>> np[0] = ( 255, 0, 0 )
>>> np[11] = ( 0, 0, 0 )
>>> np.write()</code>

<p>For RGBW or RGBY LEDs.<br>
<code>>>> np = neopixel.NeoPixel( machine.Pin( 4 ), 12, bpp = 4 )
>>> np[0] = ( 255, 0, 0, 128 )</code>

<h2>DHT Sensor</h2>
<p>Temperature in celcius, humidity in percent.<br>
<code>>>> import machine, dht
>>> dht11 = dht.DHT11( machine.Pin( 4 ) )
>>> dht22 = dht.DHT22( machine.Pin( 5 ) )
>>> dht22.measure()
>>> dht22.temperature()
>>> dht22.humidity()
>>> time.sleep_ms( 2000 )</code><br>
Pin configuration. Some support I2C, too.<br>
DHT11, DHT22, AM2301, AM2302: 1-VDD 2-DATA 3-NC 4-GND.<br>
DHT12, AM2320, AM2321, AM2322: 1-VDD 2-DATA 3-GND 4-GND also 1-VDD 2-SDA 3-GND 4-SCL.<br>
Data, SDA, SCL use pull-up.

<h2>NodeMCU Pins</h2>
NodeMCU pin label to ESP8266 pin<br><code>Label D0 - GPIO 16 (User, Wake)
Label D1 - GPIO_5
Label D2 - GPIO_4
Label D3 - GPIO_0  (Flash)
Label D4 - GPIO_2
Label D5 - GPIO_14 (,     HSclk)
Label D6 - GPIO_12 (,     HMiso)
Label D7 - GPIO_13 (Rxd2, HMosi)
Label D8 - GPIO_15 (Txd2, HCS)
Label RX - GPIO 3  (Rxd0)
Label TX - GPIO 1  (Txd0)
Label SK - SCLK    (SDClk)
Label S0 - MISO    (SDD0)
Label SC - CS      (SDCmd)
Label S1 - MOSI    (SDD1)
Label S2 - GPIO 9  (SDD2)
Label S3 - GPIO 10 (SDD3)
Label A0 - ADC0    (TOut)
</code>
</code>
</code>

<h2>Adafruit AMPY</h2>
<code>>>> import esp
>>> esp.osdebug(None)
$ pip install adafruit-ampy
$ ampy --help
$ ampy --port /dev/ttyUSB0 run test.py
$ ampy --port /dev/ttyUSB0 put src dest
$ ampy --port /dev/ttyUSB0 get src dest
$ ampy --port /dev/ttyUSB0 mkdir foobar
$ ampy --port /dev/ttyUSB0 ls
$ ampy --port /dev/ttyUSB0 rmdir foobar
$ ampy --port /dev/ttyUSB0 rm foo</code>