METF Python Client

Test your hardware by ESP using HTTP requests.

Goal

Continuous Integration in hardware development

Start

1. Connect you MCU to ESP
2. Upload METF firmware to ESP
3. Write Python test script and run it.

Equipment

• ESP board. It will be a HTTP web server controlled by PC
• Python or another HTTP request stuff to write a tests

Default board: NodeMCU. Change platformio.ini file to use another WeMos or etc.

Actions

ping

Check link

api.ping()

What ESP do: Return: 'pong'

DIO

pinMode

Set pin mode as you usually do on C.

api.pinMode(pin, mode) 

What ESP do: pinMode(pin, mode) Return: 'OK'

digitalRead

Read DIO pin

api.digitalRead(pin) 

What ESP do: digitalRead(pin) Return: 1 or 0

digitalWrite

Write value to DIO pin

api.digitalWrite(pin, value) 

What ESP do: digitalWrite(pin, value) Return: 'OK'

i2c communication

Start

api.i2c_begin() 

What ESP do: Wire.begin(SDA, SCL) Return: 'OK'

or set your pins

api.i2c_begin(sda_pin, scl_pin) 

Wire.begin(sda_pin, scl_pin)

Set clock speed

api.i2c_setClock(value) 

What ESP do: Wire.setClock(value) Return: 'OK'

Set stretch limit

api.i2c_setClockStretchLimit(stretch) 

What ESP do: Wire.setClockStretchLimit(stretch) Return: 'OK'

Send & receive message

slave_address - address of i2c slave device message - string response_length - home many bytes will read after send

ret = api.i2c_ask(slave_address, message, response_length) 

What ESP do:

Wire.beginTransmission(slave_address)

LOOP
	Wire.write(arr[i])

Wire.endTransmission()

LOOP 
	Wire.requestFrom(address, 1)
	Wire.read()

Return: code 200: response code 500: error message

ESP Firmware

Based on https://github.com/me-no-dev/ESPAsyncWebServer

Examples

Blynk

Blynk NodeMCU onboard LED

from ESPTestFramework import ESPTestFramework, LOW, HIGH, INPUT, OUTPUT

api = ESPTestFramework(host)

pin = LED_BUILTIN_AUX

api.pinMode(pin, OUTPUT)
api.digitalWrite(pin, LOW)

assert api.digitalRead(pin) == LOW

api.delay(1000)
api.digitalWrite(pin, HIGH)

assert api.digitalRead(pin) == HIGH

Check button pressed

api = ESPTestFramework(host)

api.pinMode(D5, INPUT_PULLUP)
assert api.wait_digital(D5, LOW, 3.0), "Button wasn't pressed"

Check button pressed

api = ESPTestFramework(host)

api.pinMode(D5, INPUT_PULLUP)
assert api.wait_digital(D5, LOW, 3.0), "Button wasn't pressed"

i2c communication

from ESPTestFramework import ESPTestFramework

api = ESPTestFramework(host)

api.i2c_begin(D3, D4)   #  call Wire.begin(D3, D4)

message = 'M'           #  send 1 byte '4D'
answer_len = 1          #  read 1 byte in the answer

ret = api.i2c_ask(address, message, answer_len)

assert ord(ret[0]) == 1, 'response not 1'

Unpack binary structures

from ESPTestFramework import ESPTestFramework
from ESPTestFramework.utils import DataStruct

api = ESPTestFramework(host)

api.i2c_begin(D3, D4)

fields = [  ('version',      'B'),  # unsigned char
            ('value_uint16', 'H'),  # unsigned short
            ('value_uint32', 'L'),  # unsigned long
        ]

header_len = DataStruct.calcsize(fields)

ret = api.i2c_ask(12, 'A', header_len)

header = DataStruct(fields, ret)

print header.version
print header.value_uint16
print header.value_uint32

ToDo

1. AVR ISP programmer by ESP to upload firmwares