pwm!

Author: ladyada

adafruit_seesaw/attiny8x7.py

@@ -21,12 +21,6 @@ def const(x):
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_seesaw.git"
 
 
-_PWM_0_PIN = const(0x04)
-_PWM_1_PIN = const(0x05)
-_PWM_2_PIN = const(0x06)
-_PWM_3_PIN = const(0x07)
-
-
 class ATtiny8x7_Pinmap:
     """This class is automatically used by `adafruit_seesaw.seesaw.Seesaw` when
     a ATtiny8x7 Breakout is detected.
@@ -37,10 +31,10 @@ class ATtiny8x7_Pinmap:
     analog_pins = (0, 1, 2, 3, 6, 7, 18, 19, 20)
 
     """The effective bit resolution of the PWM pins"""
-    pwm_width = 8
+    pwm_width = 16  # we dont actually use all 16 bits but whatever
 
     """The pins capable of PWM output"""
-    pwm_pins = (_PWM_0_PIN, _PWM_1_PIN, _PWM_2_PIN, _PWM_3_PIN)
+    pwm_pins = (0, 1, 9, 12, 13)
 
     """No pins on this board are capable of touch input"""
     touch_pins = ()

adafruit_seesaw/seesaw.py

@@ -342,20 +342,19 @@ def digital_write_bulk_b(self, pins, value):
 
     def analog_write(self, pin, value):
         """Set the value of an analog output by number"""
-        pin_found = False
+        if pin not in self.pin_mapping.pwm_pins:
+            raise ValueError("Invalid PWM pin")
+
+        if self.chip_id == _ATTINY8X7_HW_ID_CODE:
+            offset = pin
+        elif self.chip_id == _SAMD09_HW_ID_CODE:
+            offset = self.pin_mapping.pwm_pins.index(pin)
+            
         if self.pin_mapping.pwm_width == 16:
-            if pin in self.pin_mapping.pwm_pins:
-                pin_found = True
-                cmd = bytearray(
-                    [self.pin_mapping.pwm_pins.index(pin), (value >> 8), value & 0xFF]
-                )
+            cmd = bytearray([offset, (value >> 8), value & 0xFF])
         else:
-            if pin in self.pin_mapping.pwm_pins:
-                pin_found = True
-                cmd = bytearray([self.pin_mapping.pwm_pins.index(pin), value])
+            cmd = bytearray([offset, value])
 
-        if pin_found is False:
-            raise ValueError("Invalid PWM pin")
         self.write(_TIMER_BASE, _TIMER_PWM, cmd)
         time.sleep(0.001)
 

examples/seesaw_pwmout_test.py

@@ -0,0 +1,25 @@
+# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
+# SPDX-License-Identifier: MIT
+
+# Simple seesaw test for writing PWM outputs
+# On the SAMD09 breakout these are pins 5, 6, and 7
+# On the ATtiny8x7 breakout these are pins 0, 1, 9, 12, 13
+#
+# See the seesaw Learn Guide for wiring details:
+# https://learn.adafruit.com/adafruit-seesaw-atsamd09-breakout?view=all#circuitpython-wiring-and-test
+
+import time
+import board
+from adafruit_seesaw import seesaw, pwmout
+
+i2c_bus = board.I2C()
+ss = seesaw.Seesaw(i2c_bus)
+
+PWM_PIN = 9  # change to a valid PWM output!
+pwm = pwmout.PWMOut(ss, PWM_PIN)
+
+while True:
+    # the API PWM range is 0 to 65535, but we increment by 256 since our
+    # resolution is often only 8 bits underneath
+    pwm.duty_cycle = (pwm.duty_cycle + 256) % 65536
+    time.sleep(0.01)