Created
May 8, 2023 12:35
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(Python) A class representing a PCF8574 I2C I/O expander chip.
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| class PCF8574: | |
| """A class representing a PCF8574 I2C I/O expander chip.""" | |
| def __init__(self, i2c, address): | |
| """ | |
| Initializes a new PCF8574 instance. | |
| Args: | |
| i2c: The I2C bus the device is connected to. | |
| address: The I2C address of the device. | |
| """ | |
| self._i2c=i2c | |
| self._address=address | |
| def _pin_to_integer(self, p0=None, p1=None, p2=None, p3=None, p4=None, p5=None, p6=None, p7=None): | |
| """ | |
| Converts pin states to an integer value representing a byte. | |
| Args: | |
| p0-p7: The state of each pin. Leave as None to ignore, or set to True or False to check. | |
| Returns: | |
| An integer value representing the state of each pin as a byte. | |
| """ | |
| byte_value = 0x00 | |
| if p0 is not None and p0: | |
| byte_value |= 0x01 | |
| if p1 is not None and p1: | |
| byte_value |= 0x02 | |
| if p2 is not None and p2: | |
| byte_value |= 0x04 | |
| if p3 is not None and p3: | |
| byte_value |= 0x08 | |
| if p4 is not None and p4: | |
| byte_value |= 0x10 | |
| if p5 is not None and p5: | |
| byte_value |= 0x20 | |
| if p6 is not None and p6: | |
| byte_value |= 0x40 | |
| if p7 is not None and p7: | |
| byte_value |= 0x80 | |
| return int(byte_value) | |
| def set_pin_state(self, p0=None, p1=None, p2=None, p3=None, p4=None, p5=None, p6=None, p7=None): | |
| """ | |
| Sets the state of the specified pins. | |
| Args: | |
| p0-p7: The state of each pin. Leave as None to ignore, or set to True or False to set the state. | |
| """ | |
| self._i2c.writeto(self._address, bytearray([self._pin_to_integer(p0, p1, p2, p3, p4, p5, p6, p7)])) | |
| def get_pin_state(self, p0=None, p1=None, p2=None, p3=None, p4=None, p5=None, p6=None, p7=None): | |
| """ | |
| Gets the state of the specified pins. | |
| Args: | |
| p0-p7: The state of each pin. Leave as None to ignore, or set to True or False to check. | |
| Returns: | |
| True if the specified pins are set, otherwise False. | |
| """ | |
| i = self._pin_to_integer(p0, p1, p2, p3, p4, p5, p6, p7) | |
| return self._i2c.readfrom(self._address, 1)[0] & i == i | |
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