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83 lines
2.4 KiB
83 lines
2.4 KiB
5 years ago
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#!/usr/bin/env python3
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# Python library to control Zookeeper
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import ft4222
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import ft4222.I2CMaster
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DEBUG = False
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INA231_ADDR = 0x40
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INA231_REG_CONFIG = 0x00
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INA231_REG_SHUNT_VOLTAGE = 0x01
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INA231_REG_BUS_VOLTAGE = 0x02
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INA231_REG_POWER = 0x03
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INA231_REG_CURRENT = 0x04
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INA231_REG_CALIBRATION = 0x05
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INA231_BUS_LSB = 1.25e-3
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INA231_SHUNT_LSB = 2.5e-6
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SHUNT_RESISTOR = 30e-3
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CURRENT_LSB = 1e-5
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class Zookeeper:
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def __init__(self):
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if ft4222.createDeviceInfoList() < 2:
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raise Exception("No connected zookeeper found!")
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self.dev_a = ft4222.openByDescription("FT4222 A")
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self.dev_b = ft4222.openByDescription("FT4222 B")
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if DEBUG:
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for i in range(ft4222.createDeviceInfoList()):
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print(f"Device {i}: {ft4222.getDeviceInfoDetail(i, False)}")
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# Setup GPIO
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self.dev_b.gpio_Init(gpio2=ft4222.Dir.OUTPUT, gpio3=ft4222.Dir.OUTPUT)
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self.dev_b.setSuspendOut(False)
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self.dev_b.setWakeUpInterrut(False)
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# Setup I2C
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self.dev_a.i2cMaster_Init(kbps=400)
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self._initialize_ina()
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# Helper functions
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def _read_ina_register(self, register, length):
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self.dev_a.i2cMaster_WriteEx(INA231_ADDR, data=register, flag=ft4222.I2CMaster.Flag.REPEATED_START)
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return self.dev_a.i2cMaster_Read(INA231_ADDR, bytesToRead=length)
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def _write_ina_register(self, register, data):
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msg = register.to_bytes(1, byteorder="big") + data.to_bytes(2, byteorder="big")
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self.dev_a.i2cMaster_Write(INA231_ADDR, data=msg)
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def _initialize_ina(self):
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# Config
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self._write_ina_register(INA231_REG_CONFIG, 0x4127)
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# Calibration
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CAL_VALUE = int(0.00512 / (CURRENT_LSB * SHUNT_RESISTOR))
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if DEBUG:
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print(f"Calibration value: {hex(CAL_VALUE)}")
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self._write_ina_register(INA231_REG_CALIBRATION, CAL_VALUE)
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def _set_gpio(self, number, enabled):
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self.dev_b.gpio_Write(portNum=number, value=enabled)
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# Public API functions
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def set_device_power(self, enabled):
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self._set_gpio(2, enabled)
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def set_device_ignition(self, enabled):
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self._set_gpio(3, enabled)
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def read_current(self):
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# Returns in A
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return int.from_bytes(self._read_ina_register(INA231_REG_CURRENT, 2), byteorder="big") * CURRENT_LSB
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def read_power(self):
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# Returns in W
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return int.from_bytes(self._read_ina_register(INA231_REG_POWER, 2), byteorder="big") * CURRENT_LSB * 25
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def read_voltage(self):
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# Returns in V
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return int.from_bytes(self._read_ina_register(INA231_REG_BUS_VOLTAGE, 2), byteorder="big") * INA231_BUS_LSB
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