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Bench Power Module - Library Reference

This is the library reference for the Bench Power Module for Yukon.

Getting Started

To start using a Bench Power Module, you first need to import the class from pimoroni_yukon.modules.

from pimoroni_yukon.modules import BenchPowerModule

Then create an instance of BenchPowerModule.

module = BenchPowerModule()

Initialising the Module

As with all Yukon modules, BenchPowerModule must be initialised before it can be used. This is achieved by first registering the module with the Yukon class, with the slot it is attached to.

from pimoroni_yukon import SLOT1 as SLOT

# Import and set up Yukon and BenchPowerModule instances

yukon.register_with_slot(module, SLOT)

Then Yukon can verify and initialise its modules.

yukon.verify_and_initialise()

This checks each slot on the board to see if the modules expected by your program are physically attached to the board. Only if they match will the BenchPowerModule be initialised, giving it access to the GPIO of the slot it is attached to.

Power can now be provided to all modules, by calling.

yukon.enable_main_output()

Using the Module

Controlling its Output

With the BenchPowerModule powered, its output can be enabled or disabled by calling .enable() or .disable(). The state can also be queried by calling .is_enabled().

Changing its Voltage

The output voltage of the Bench Power module can be changed in two ways.

The first is by calling .set_voltage(voltage), and providing it with a voltage up to 12.4V.

The second is by calling .set_percent(percent), and providing it with a value from 0.0 to 1.0.

Reading back Voltage

The Bench Power module features a voltage divider, letting its output be measured by calling .read_voltage().

⚠️ Due to variations in component values on the Bench Power module and Yukon board itself, the voltage returned by this function may over or under report what is actually output. The BenchPowerModule class performs a 3-point conversion to mitigate this, but if absolute accuracy is needed for your application then the following constants should be modified with assistance of an external multimeter:

# The PWM range the voltage points are over, with 0.0 resulting in the maximum voltage
PWM_MIN = 0.3
PWM_MAX = 0.0

# The three voltage points produced by those PWM values, used for conversion
VOLTAGE_AT_PWM_MIN = 0.6017
VOLTAGE_AT_PWM_MID = 6.4864
VOLTAGE_AT_PWM_MAX = 12.4303

# The ADC values (between 0.0 and 3.3) measured at the three PWM values
MEASURED_AT_PWM_MIN = 0.1439
MEASURED_AT_PWM_MID = 1.3094
MEASURED_AT_PWM_MAX = 2.4976

Onboard Sensors

The Bench Power module features an onboard thermistor, letting its temperature be monitored. This can be read by calling .read_temperature().

Additionally, the power good status of the onboard regulator can be read by calling .read_power_good(). This will be True during normal operation, but will switch to False under various conditions such as the input voltage dropping below what is needed for the module to achieve a stable output. For details of other conditions, check the TPS54A24 datasheet.

Reference

Constants

NAME = "Bench Power"
PWM_MIN = 0.3
PWM_MAX = 0.0
VOLTAGE_AT_PWM_MIN = 0.6017
VOLTAGE_AT_PWM_MID = 6.4864
VOLTAGE_AT_PWM_MAX = 12.4303
MEASURED_AT_PWM_MIN = 0.1439
MEASURED_AT_PWM_MID = 1.3094
MEASURED_AT_PWM_MAX = 2.4976
TEMPERATURE_THRESHOLD = 80.0

Variables

halt_on_not_pgood: bool

FAST3 = Pin
FAST4 = Pin

Methods

# Address Checking
@staticmethod
is_module(adc1_level: int, adc2_level: int, slow1: bool, slow2: bool, slow3: bool) -> bool

# Initialisation
BenchPowerModule(halt_on_not_pgood: bool=False)
initialise(slot: SLOT, adc1_func: Callable, adc2_func: Callable) -> None
reset() -> None

# Power Control
enable() -> None
disable() -> None
is_enabled() -> bool

# Output Control
set_voltage(voltage: float) -> None
set_percent(percent: float) -> None

# Sensing
read_voltage(samples: int=1) -> float
read_power_good() -> bool
read_temperature(samples: int=1) -> float

# Monitoring
monitor() -> None
get_readings() -> OrderedDict
process_readings() -> None
clear_readings() -> None