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HPE-GL20-GPIO

This is the sample python script for accessing the HPE GL20 IoT Gateway's GPIO. This is not the official module support, use it on your own risk.

gRPC Service

You might want to use gRPC server to speed up deployment https://github.com/helloezmeral/HPE-GL20-gRPC

Getting Started

Background

You need to have HPE GL20 IoT Gateway, purchase it via local channel:

image

You can check the offical document here

Important information

This configuration is routed internally and cannot be changed. Using other configuration could cause damgae to the internal circuitry.

\

Digital I/O PIN0-5 PIN6-7 PIN8-9
- DI DO GND
DI Pull-up
DO Open collector

Note:
Pull-up: If nothing is connected to input pins, it reads as logical high. Connect to ground
Open Collector: Output high means Open Circuit; Output Low means Short Circuit

STEP 1: Set up Environment

# Installing the i2ctools
sudo apt install i2c-tools

STEP 2: Check the Environment Variable

# detect which smbus is the used

# run if devices is not visible on the initial list of i2c device. Run this:
# sudo modprobe i2c-i801 
sudo i2cdetect -l

NOTE: look for the one with name SMBus I801 adapter at f040. This will be in format of i2c-x.

  • This output shows the I2C connector is conected as Bus 0.

STEP 3: Python Setup

# install smbus2 library
sudo pip3 install smbus2

Happy hacking: Accessing the peripheral require root access

sudo python

Getting Started

Import Module

# download the python module for connecting the GPIO
# put it under same directory
wget https://raw.githubusercontent.com/cenzwong/HPE-GL20-GPIO/master/pyGL20.py

Python Code

# import python pyGL20 GPIO module
from pyGL20 import GPIO

# Initiate I2C bus zero communication
IO = GPIO(0) # This means i2c-0

# Write Logic High on pin 6
IO.digitalWrite(IO.PIN6, True)

# Toggle Logic on pin 7 
IO.digitalToggle(IO.PIN(7), True)

# Read Logic on pin 1 
IO.digitalRead(IO.PIN(1))

Module pyGL20 Code Example

  • Example Blink code
# blink.py
from pyGL20 import GPIO
import time

"""
Please run 
::
sudo i2cdetect -l
::
to find the coresponding i2c-x bus of "SMBus I801 adapter at f040"
replace the number x of the below variable.
"""
IO = GPIO(0) # This means i2c-0

while True:
    print(IO.digitalWrite(IO.PIN6, True))
    time.sleep(0.1)
    print(IO.digitalWrite(IO.PIN(6), False)) # both work
    time.sleep(0.1)
  • More

digitalRead/digitalReadAll

  • Read logical high/low on specific pin/all pins
digitalReadAll(self) -> int:
"""Read all pin and return in byte form

Return
----------
int
    - a value specify all state including OUTPUT port. 0 is LOW, 1 is HIGH
"""
digitalRead(self, PINx) -> bool:
"""Read a specific pin and return True if Logic HIGH

Parameters
----------
PINx : PIN0, PIN1, ... PIN7

Return
----------
bool
    - a value specify all state including OUTPUT port. 0 is LOW, 1 is HIGH
"""

digitalWrite/digitalWriteAll/digitalWriteToggle/digitalWriteToggleAll

  • Write/Toggle logical high/low on specific pin/all pins
digitalWriteAll(value: int):
"""Assign both PIN6 and PIN7 simultaneously

Parameters
----------
value : int
    - The value must be within *0-3*. 
    - This represent 0b00, 0b01, 0b10, 0b11
"""
digitalWrite(PINx, logic: bool):
"""Write a specific pin

Parameters
----------
PINx : PIN6, PIN7 **ONLY**
Logic: 0,1,True, False
"""
digitalWriteToggle(PINx):
"""Toggle the OUTPUT port specific pin (PIN6, PIN7)"""
digitalWriteToggleAll():
"""Toggle the OUTPUT port pins (PIN6, PIN7)"""