108 lines
2.8 KiB
Python
108 lines
2.8 KiB
Python
# SPDX-License-Identifier: LGPL-3.0-or-later
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# Copyright (C) 2020 Daniel Thompson
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"""Hynitron CST816S touch contoller driver
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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"""
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import array
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import time
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from machine import Pin
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class CST816S:
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"""Hynitron CST816S I2C touch controller driver.
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.. automethod:: __init__
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"""
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def __init__(self, bus, intr, rst, schedule=None):
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"""Specify the bus used by the touch controller.
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:param machine.I2C bus: I2C bus for the CST816S.
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"""
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self.i2c = bus
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self.tp_int = intr
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self.tp_rst = rst
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self.schedule = schedule
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self.dbuf = bytearray(6)
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self.event = array.array('H', (0, 0, 0))
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self._reset()
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self.tp_int.irq(trigger=Pin.IRQ_FALLING, handler=self.get_touch_data)
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def _reset(self):
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self.tp_rst.off()
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time.sleep_ms(5)
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self.tp_rst.on()
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time.sleep_ms(50)
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def version(self):
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self.wake()
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v = self.i2c.readfrom_mem(21, 0xa6, 4)
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self.sleep()
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return v
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def get_touch_data(self, pin_obj):
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"""Receive a touch event by interrupt.
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Check for a pending touch event and, if an event is pending,
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prepare it ready to go in the event queue.
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"""
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dbuf = self.dbuf
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event = self.event
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try:
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self.i2c.readfrom_mem_into(21, 1, dbuf)
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except OSError:
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return None
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event[0] = dbuf[0] # event
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event[1] = ((dbuf[2] & 0xf) << 8) + dbuf[3] # x coord
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event[2] = ((dbuf[4] & 0xf) << 8) + dbuf[5] # y coord
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if self.schedule:
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self.schedule(self)
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def get_event(self):
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"""Receive a touch event.
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Check for a pending touch event and, if an event is pending,
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prepare it ready to go in the event queue.
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:return: An event record if an event is received, None otherwise.
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"""
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if self.event[0] == 0:
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return None
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return self.event
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def reset_touch_data(self):
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"""Reset touch data.
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Reset touch data, call this function after processing an event.
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"""
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self.event[0] = 0
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def wake(self):
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"""Wake up touch controller chip.
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Just reset the chip in order to wake it up
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"""
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self._reset()
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self.event[0] = 0
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def sleep(self):
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"""Put touch controller chip on sleep mode to save power.
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"""
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# Before we can send the sleep command we have to reset the
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# panel to get the I2C hardware running again...
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self._reset()
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try:
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self.i2c.writeto_mem(21, 0xa5, b'\x03')
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except:
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# If we can't power down then let's just put it in reset instead
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self.tp_rst.off()
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# Ensure get_event() cannot return anything
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self.event[0] = 0
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