roboglia.base.BaseRegister

class BaseRegister(name='REGISTER', device=None, address=0, clone=None, size=1, minim=0, maxim=None, access='R', sync=False, word=False, bulk=True, order='LH', default=0, **kwargs)

Bases: object

A minimal representation of a device register.

Parameters

• name (str) – The name of the register

• device (BaseDevice or subclass) – The device where the register is attached to

• address (int (typpically but some devices might use other addressing)) – The register address

• size (int) – The register size in bytes; defaults to 1

• minim (int) – Minimum value represented in register in internal format; defaults to 0

• maxim (int) – Maximum value represented in register; defaults to 2^size - 1. The setter method for internal value will check that the desired value is within the [min, max] and trim it accordingly

• access (str) – Read (‘R’) or read-write (‘RW’); default ‘R’

• clone (BaseRegister or subclass or None) –

  Indicates if the register is a clone; this value provides the reference to the register object that acts as the main register in interation with the communication bus. This allows you to define multiple represtnations of the same physical register (at a given address) with the purpose of having different external representations. For example:

  • you can have a position register that can provide the external value in degrees or radians,

  • a velocity register that can provide the external value in degrees per second, radians per second or rotations per minute,

  • a byte register that reads 8 inputs and mask them each as a BoolRegister with a different bit mask

  In the device definition YAML file use True to indicate if a register is a clone. The device constructor will replace the reference of the main register with the same address in the constructor of this register.

• sync (bool) – True if the register will be updated from the real device using a sync loop. If sync is False access to the register through the value property will invoke reading / writing to the real register; default False

• word (bool) – Indicates that the register is a word register (16 bits) instead of a usual 8 bits. Some I2C and SPI devices use 16bit registers and need to use separate access functions to read them as opposed to the 8 bit registers. Default is False which effectively makes it an 8 bit register

• order (LH or HL) – Applicable only for registers with size > 1 that represent a value over successive internal registers, but for convenience are groupped as one single register with size 2 (or higher). LH means low-high and indicates the bytes in the registry are organized starting with the low byte first. HL indicates that the registers are with the high byte first. Technically the read and write functions always read the bytes in the order they are stored in the device and if the register is marked as HL the list is reversed before being returned to the requester or processed as a number in case the bulk is False. Default is LH.

• default (int) – The default value for the register; implicit 0

__init__(name='REGISTER', device=None, address=0, clone=None, size=1, minim=0, maxim=None, access='R', sync=False, word=False, bulk=True, order='LH', default=0, **kwargs)

Initialize self. See help(type(self)) for accurate signature.

property name

Register’s name.

property device

The device the register belongs to.

property address

The register’s address in the device.

property clone

Indicates the register is a clone of another.

property size

The regster’s size in Bytes.

property minim

The register’s minimum value in internal format.

property maxim

The register’s maximum value in internal format.

property range

Tuple with (minim, maxim) values in internal format.

property min_ext

The register’s minimum value in external format.

property max_ext

The register’s maximum value in external format.

property range_ext

Tuple with (minim, maxim) values in external format.

property access

Register’s access mode.

property sync

Register is subject to a sync loop update.

property word

Indicates if the register is an 16 bit register (True) or an 8 bit register.

property order

Indicates the order of the data representartion; low-high (LH) or high-low (HL)

property default

The register’s default value in internal format.

property int_value

Internal value of register, if a clone return the value of the main register.

value_to_external(value)

Converts the presented value to external format according to register’s settings. This method should be overridden by subclasses in case they have specific conversions to do.

Parameters

value (int) – A value (internal representation) to be converted.

Returns

For BaseRegister it returns the same value unchanged.

Return type

int

value_to_internal(value)

Converts the presented value to internal format according to register’s settings. This method should be overridden by subclasses in case they have specific conversions to do.

Parameters

value (int) – A value (external representation) to be converted.

Returns

For BaseRegister it returns the same value unchanged.

Return type

int

property value

Provides the value of the register in external format. If the register is not marked for sync then it requests the device to perform a read in order to refresh the content of the register.

Returns

The value of the register in the external format. It invokes value_to_external() which can be overridden by subclasses to provide different representations of the register’s value (hence the any return type).

Return type

any

write()

Performs the actual writing of the internal value of the register to the device. Calls the device’s method to write the value of register.

read()

Performs the actual reading of the internal value of the register from the device. Calls the device’s method to read the value of register.

__str__()

Representation of the register [name]: value.