Source code for pynq.lib.pmod.pmod_grove_tmp

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from math import log
from . import Grove_ADC


__author__ = "Yun Rock Qu"
__copyright__ = "Copyright 2016, Xilinx"
__email__ = "pynq_support@xilinx.com"


[docs]class Grove_TMP(Grove_ADC): """This class controls the grove temperature sensor. This class inherits from the Grove_ADC class. To use this module, grove ADC has to be used as a bridge. The temperature sensor uses a thermistor to detect the ambient temperature. Hardware version: v1.2. Attributes ---------- microblaze : Pmod Microblaze processor instance used by this module. log_running : int The state of the log (0: stopped, 1: started). log_interval_ms : int Time in milliseconds between sampled reads. bValue : int The thermistor constant. """ def __init__(self, mb_info, gr_pin, version='v1.2'): """Return a new instance of a Grove_TMP object. Note ---- The parameter `gr_pin` is a list organized as [scl_pin, sda_pin]. Parameters ---------- mb_info : dict A dictionary storing Microblaze information, such as the IP name and the reset name. gr_pin: list A group of pins on pmod-grove adapter. version : str The hardware version number (can be found on device). """ if version == 'v1.2': # v1.2 uses NCP18WF104F03RC self.bValue = 4250 elif version == 'v1.1': # v1.1 uses thermistor NCP18WF104F03RC self.bValue = 4250 else: # v1.0 uses thermistor TTC3A103*39H self.bValue = 3975 super().__init__(mb_info, gr_pin)
[docs] def read(self): """Read temperature values in Celsius from temperature sensor. This method overrides the definition in Grove_ADC. Returns ------- float The temperature reading in Celsius. """ # Transform the ADC data into degree Celsius val = super().read_raw() return self._int2temp(val)
[docs] def start_log(self): """Start recording temperature in a log. This method will call the start_log_raw() in the parent class. """ super().start_log_raw()
[docs] def get_log(self): """Return list of logged temperature samples. Returns ------- list List of valid temperature readings from the temperature sensor. """ # Stop and get the log tmp_log = super().get_log_raw() return [self._int2temp(i) for i in tmp_log]
[docs] def stop_log(self): """Stop recording temperature in a log. This method will call the stop_log_raw() in the parent class. Returns ------- None """ super().stop_log_raw()
def _int2temp(self, val): """Convert the integer value to temperature in Celsius. This method should only be used internally. Parameters ---------- val : int The raw data read from grove ADC. Returns ------- float The temperature reading in Celsius. """ try: r = 4095.0/val - 1.0 temp = 1.0/(log(r)/self.bValue + 1/298.15)-273.15 except ZeroDivisionError: raise RuntimeError("Value out of range or device not connected.") return float("{0:.2f}".format(temp))