A library for modelling devices and their connections in the physical world and controlling them in the virtual world through auto generated source code for the raspberry pi.
py_connect provides a DSL (Domain Specific Language) for defining devices and connections between them. The DSL has been built using textx and through custom parsers the defined models are translated to ecore models using pyecore.
usage: py_connect [-h] [--device DEVICE] [--store] [--xmi]
[--xmi_path XMI_PATH] [--db_path DB_PATH]
[--connections CONNECTIONS] [--source]
[--schematic] [--specific_con SPECIFIC_CON]
[--update_pidevices]
optional arguments:
-h, --help show this help message and exit
--device DEVICE Path to a device specification.
--store Move device specification to db.
--xmi Export xmi.
--xmi_path XMI_PATH Folder for saving xmi files.
--db_path DB_PATH Path to custom devices db.
--connections CONNECTIONS
Path to a connection specification.
--source Flag for generating source code.
--schematic Flag for generating schematics images.
--specific_con SPECIFIC_CON
The name of the specific connection.
--update_pidevices Update pidevices implementations.
Assingment is declared by the character ":". An entity precedes the ":"
and it's value follows. An entity has attributes, which could be
single valued or other entities.
For example the definition of a device's name is done in a single line
name: raspberry_pi, but the device's memory is defined like this
memory:
ram: 2 gb
rom: 16 gb
Some attributes' value is a list of other entities. A list entry is defined by "-" followed by it's value. For example the pins of a device are defined by
pins:
- power:
name: power_5v_1
number: 2
type: 5v
- io_digital: -> both, sda-1
name: bcm_2
number: 3
A device could be either a peripheral device (sensor/actuator) or a board (raspberry pi). The following table contains all the attributes and their values that define a device and whether they are mandatory or not for a valid definition.
| Attribute | Board | Peripheral | Mandatory | Value |
|---|---|---|---|---|
| name | x | x | x | string |
| vcc | x | x | x | number |
| operating_voltage | x | x | x | number |
| pins | x | x | x | [pin entities] |
| network | x | x | - | [network entities] |
| bluetooth | x | x | - | bluetooth entity |
| type | - | x | x | "sensor" | "actuator" |
| memory | x | - | x | memory entity |
| timer | x | - | x | bool |
| os | x | - | x | "raspbian" |
| cpu | x | - | x | cpu entity |
| rtc | x | - | - | bool |
| battery | x | - | - | bool |
| dma | x | - | - | bool |
The pins could be either power pins or gpios.
-
Power pins
power: name: string number: number type : "gnd" | "3v3" | "5v" -
Gpio pins
io_digital: -> functionalities name: string number: numberThe functionalities is list of strings separated by commas. The strings declare a pin functionality related to a hardware interface.
- gpio: "input" | "output" | "both"
- i2c: "sda" | "scl"
- spi: "mosi" | "miso" | "sclk" | "ce"
- uart: "rx" | "tx"
- pwm: "pwm"
Except the gpio functionalities the functionalities of the other interfaces are followed by the interface's id. An example pin could be defined like this
io_digital: -> both, sda-1 number: 2 name: bcm_2
The network entities could be either of type wifi or ethernet
- Wifi
wifi: name: string freq: freq_1 , freq_2 unit - Ethernet
ethernet: name: string
The memory entity describes the different types of memory a device could support and their values.
memory:
ram: int unit
rom: int unit
external_memory: int unit
Where value is an integer number and unit could be on of "mb", "kb", "gb" and "b".
A CPU entitie describes the cpu architecture, its maximum frequency and fpu support.
cpu:
cpu_family: ARM_CORTEX_M | ARM_CORTEX_A | ESP32
max_freq: number unit(hz | ghz)
fpu: bool
A bluetooth entitie describes a device's bluetooth support.
bluetooth:
version: number
A connection between two devices is defined by the connection of their hardware interfaces ports and of their power pins.
| Attribute | Mandatory | Value |
|---|---|---|
| name | x | string |
| board | x | string |
| peripheral | x | string |
| peripheral_impl | x | string |
| operating_voltage | x | x |
| power_connections | x | [power_connection_entities] |
| hw_connections | x | [hw_connection_entities] |
The peripheral and board attributes must have the names of valid devices which have been already included in the file and defined in a different file.
power_connections:
- board_pin -- peripheral_pin
- board_pin_1 -- peripheral_pin_1
Where board_pin and peripheral_pin are the names attributes of power pins from the corresponding devices.
hw_connections:
- type: board_hw_int -- peripheral_hw_int
- type: board_hw_int_1 -- peripheral_hw_int_
The type describes the connection type and the value could be one of "gpio", "spi", "i2c", "uart" and "pwm". The values that follow are the names of the hardware interfaces in each device, e.g.
- i2c: i2c-1 -- i2c-0
First comes the interface of the board device and then follows the peripheral's. The name of the pin is used for the interfaces which use only one pin (gpio and pwm).
After the definations, m2t transormations are being applied on the generated models in order to transform them to ecore models.
Currently only devices connected to the raspberry pi are supported. The control of the devices is being done through the pidevices library.
After the definition of the devices and their connection has been done the source code could be generated by
$ py_connect --db_path devices --connections connection.cd --source
Where db_path is the path to the devices folder and connection.cd is the file, which contains the defined connections. The result of the command is python file named by the connection name.
To install clone the repo:
$ git clone https://github.com/iparaskev/py_connect.git
$ python setup.py install
Examples of device descriptions can be found in the db_folder. Example connections can be seen in connections_folder.