Add rotary encoder support

adafruit_seesaw/seesaw.py

@@ -61,6 +61,7 @@ def const(x):
 _EEPROM_BASE = const(0x0D)
 _NEOPIXEL_BASE = const(0x0E)
 _TOUCH_BASE = const(0x0F)
+_ENCODER_BASE = const(0x11)
 
 _GPIO_DIRSET_BULK = const(0x02)
 _GPIO_DIRCLR_BULK = const(0x03)
@@ -109,6 +110,12 @@ def const(x):
 _HW_ID_CODE = const(0x55)
 _EEPROM_I2C_ADDR = const(0x3F)
 
+_ENCODER_STATUS = const(0x00)
+_ENCODER_INTENSET = const(0x10)
+_ENCODER_INTENCLR = const(0x20)
+_ENCODER_POSITION = const(0x30)
+_ENCODER_DELTA = const(0x40)
+
 # TODO: update when we get real PID
 _CRICKIT_PID = const(9999)
 _ROBOHATMM1_PID = const(9998)
@@ -362,6 +369,31 @@ def set_pwm_freq(self, pin, freq):
         else:
             raise ValueError("Invalid PWM pin")
 
+    def get_encoder_pos(self, encoder=0):
+        """Read the current position of the encoder"""
+        buf = bytearray(4)
+        self.read(_ENCODER_BASE, _ENCODER_POSITION + encoder, buf)
+        return struct.unpack(">i", buf)[0]
+
+    def set_encoder_pos(self, pos, encoder=0):
+        """Set the current position of the encoder"""
+        cmd = struct.pack(">i", pos)
+        self.write(_ENCODER_BASE, _ENCODER_POSITION + encoder, cmd)
+
+    def get_encoder_delta(self, encoder=0):
+        """Read the change in encoder position since it was last read"""
+        buf = bytearray(4)
+        self.read(_ENCODER_BASE, _ENCODER_DELTA + encoder, buf)
+        return struct.unpack(">i", buf)[0]
+
+    def enable_encoder_interrupt(self, encoder=0):
+        """Enable the interrupt to fire when the encoder changes position"""
+        self.write8(_ENCODER_BASE, _ENCODER_INTENSET + encoder, 0x01)
+
+    def disable_encoder_interrupt(self, encoder=0):
+        """Disable the interrupt from firing when the encoder changes"""
+        self.write8(_ENCODER_BASE, _ENCODER_INTENCLR + encoder, 0x01)
+
     # def enable_sercom_data_rdy_interrupt(self, sercom):
     #
     #     _sercom_inten.DATA_RDY = 1

examples/seesaw_rotary_simpletest.py

@@ -0,0 +1,32 @@
+# SPDX-FileCopyrightText: 2021 John Furcean
+# SPDX-License-Identifier: MIT
+
+import board
+import busio
+from adafruit_seesaw.seesaw import Seesaw
+from adafruit_seesaw.digitalio import DigitalIO
+
+i2c_bus = busio.I2C(board.SCL, board.SDA)
+
+seesaw = Seesaw(i2c_bus, addr=0x36)
+
+button = DigitalIO(seesaw, 24)
+button_held = False
+
+last_pos = seesaw.get_encoder_pos()
+
+while True:
+
+    # read position of the rotary encoder
+    pos = seesaw.get_encoder_pos()
+    if pos != last_pos:
+        last_pos = pos
+        print(f"Position: {pos}")
+
+    if not button.value and not button_held:
+        button_held = True
+        print("Button pressed")
+
+    if button.value and button_held:
+        button_held = False
+        print("Button released")