90 lines
2.8 KiB
Python
90 lines
2.8 KiB
Python
# SPDX-FileCopyrightText: 2021 Melissa LeBlanc-Williams for Adafruit Industries
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#
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# SPDX-License-Identifier: MIT
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"""MCP2221 pin names"""
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from .mcp2221 import mcp2221
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class Pin:
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"""A basic Pin class for use with MCP2221."""
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# pin modes
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OUT = 0
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IN = 1
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ADC = 2
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DAC = 3
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# pin values
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LOW = 0
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HIGH = 1
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def __init__(self, pin_id=None):
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self.id = pin_id
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self._mode = None
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def init(self, mode=IN, pull=None):
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"""Initialize the Pin"""
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if self.id is None:
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raise RuntimeError("Can not init a None type pin.")
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if pull is not None:
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raise NotImplementedError("Internal pullups and pulldowns not supported")
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if mode in (Pin.IN, Pin.OUT):
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# All pins can do GPIO
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mcp2221.gp_set_mode(self.id, mcp2221.GP_GPIO)
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mcp2221.gpio_set_direction(self.id, mode)
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elif mode == Pin.ADC:
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# ADC only available on these pins
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if self.id not in (1, 2, 3):
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raise ValueError("Pin does not have ADC capabilities")
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mcp2221.gp_set_mode(self.id, mcp2221.GP_ALT0)
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mcp2221.adc_configure()
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elif mode == Pin.DAC:
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# DAC only available on these pins
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if self.id not in (2, 3):
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raise ValueError("Pin does not have DAC capabilities")
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mcp2221.gp_set_mode(self.id, mcp2221.GP_ALT1)
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mcp2221.dac_configure()
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else:
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raise ValueError("Incorrect pin mode: {}".format(mode))
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self._mode = mode
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def value(self, val=None):
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"""Set or return the Pin Value"""
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# Digital In / Out
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if self._mode in (Pin.IN, Pin.OUT):
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# digital read
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if val is None:
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return mcp2221.gpio_get_pin(self.id)
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# digital write
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if val in (Pin.LOW, Pin.HIGH):
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mcp2221.gpio_set_pin(self.id, val)
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return None
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# nope
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raise ValueError("Invalid value for pin.")
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# Analog In
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if self._mode == Pin.ADC:
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if val is None:
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# MCP2221 ADC is 10 bit, scale to 16 bit per CP API
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return mcp2221.adc_read(self.id) * 64
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# read only
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raise AttributeError("'AnalogIn' object has no attribute 'value'")
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# Analog Out
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if self._mode == Pin.DAC:
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if val is None:
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# write only
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raise AttributeError("unreadable attribute")
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# scale 16 bit value to MCP2221 5 bit DAC (yes 5 bit)
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mcp2221.dac_write(self.id, val // 2048)
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return None
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raise RuntimeError(
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"No action for mode {} with value {}".format(self._mode, val)
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)
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# create pin instances for each pin
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G0 = Pin(0)
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G1 = Pin(1)
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G2 = Pin(2)
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G3 = Pin(3)
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SCL = Pin()
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SDA = Pin()
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