Usage examples for chaining drivers.

Author: ArthurDent62

examples/tlc5947_chain.py

@@ -0,0 +1,110 @@
+# Simple demo of controlling a chain of several TLC5947 12-bit 24-channel PWM controllers.
+# Will update channel values to different PWM duty cycles.
+# Authors: Tony DiCola, Walter Haschka
+
+import board
+import busio
+import digitalio
+
+import adafruit_tlc5947
+
+# Define pins connected to the TLC5947
+SCK = board.SCK
+MOSI = board.MOSI
+LATCH = digitalio.DigitalInOut(board.D5)
+
+# Initialize SPI bus.
+spi = busio.SPI(clock=SCK, MOSI=MOSI)
+
+# Initialize TLC5947
+DRIVER_COUNT = 2		# change this to the number of drivers you have chained
+tlc5947 = adafruit_tlc5947.TLC5947(spi, LATCH, num_drivers=DRIVER_COUNT)
+# You can optionally disable auto_write which allows you to control when
+# channel state is written to the chip.  Normally auto_write is true and
+# will automatically write out changes as soon as they happen to a channel, but
+# if you need more control or atomic updates of multiple channels then disable
+# and manually call write as shown below.
+#tlc5947 = adafruit_tlc5947.TLC5947(spi, LATCH, num_drivers=DRIVER_COUNT, auto_write=False)
+
+# There are two ways to set channel PWM values. The first is by getting
+# a PWMOut object that acts like the built-in PWMOut and can be used anywhere
+# it is used in your code.  Change the duty_cycle property to a 16-bit value
+# (note this is NOT the 12-bit value supported by the chip natively) and the
+# PWM channel will be updated.
+
+def first_last():
+    """Cycles the red pin of LED one up, then the other LED; now dims the LEDs
+    both down. Repeats with green and blue pins. Then starts all over again.
+
+    Hook up one RGB LED to pins 0 (red), 1 (green), and 2 (blue), AND connect
+    another RGB LED to pins 21, 22 and 23 of the last chained driver, respectively.
+    """
+    redA = tlc5947.create_pwm_out(0)
+    greenA = tlc5947.create_pwm_out(1)
+    blueA = tlc5947.create_pwm_out(2)
+    redZ = tlc5947.create_pwm_out(DRIVER_COUNT*24-3)
+    greenZ = tlc5947.create_pwm_out(DRIVER_COUNT*24-2)
+    blueZ = tlc5947.create_pwm_out(DRIVER_COUNT*24-1)
+
+    step = 10
+    start_pwm = 0
+    end_pwm = 32767 # 50% (32767, or half of the maximum 65535):
+
+    while True:
+        for (pinA, pinZ) in ((redA, redZ), (greenA, greenZ), (blueA, blueZ)):
+            # Brighten:
+            print("LED A up")
+            for pwm in range(start_pwm, end_pwm, step):
+                pinA.duty_cycle = pwm
+                # tlc5947.write()        # see NOTE below
+
+            print("LED Z up")
+            for pwm in range(start_pwm, end_pwm, step):
+                pinZ.duty_cycle = pwm
+                # tlc5947.write()        # see NOTE below
+
+            # Dim:
+            print("LED A and LED Z down")
+            for pwm in range(end_pwm, start_pwm, 0 - step):
+                pinA.duty_cycle = pwm
+                pinZ.duty_cycle = pwm
+                # tlc5947.write()        # see NOTE below
+
+    # NOTE: if auto_write was disabled you need to call write on the parent to
+    # make sure the value is written in each loop (this is not common, if disabling 
+    # auto_write you probably want to use the direct 12-bit raw access instead,
+    # shown next).
+
+#----------
+# The other way to read and write channels is directly with each channel 12-bit
+# value and an item accessor syntax.  Index into the TLC5947 with the channel
+# number (0-max) and get or set its 12-bit value (0-4095).
+def test_all_channels(step):
+    """Loops over all available channels of all connected driver boards,
+    brightening and dimming all LEDs one after the other. With RGB LEDs,
+    all each component is cycled. Repeats forever.
+
+    :param step: the PWM increment in each cycle. Higher values makes cycling quicker.
+    """
+
+    start_pwm = 0
+    end_pwm = 3072 # 75% of the maximum 4095
+
+    while True:
+        for pin in range(DRIVER_COUNT*24):
+            # Brighten:
+            for pwm in range(start_pwm, end_pwm, step):
+                tlc5947[pin] = pwm
+                # Again be sure to call write if you disabled auto_write.
+                #tlc5947.write()
+
+            # Dim:
+            for pwm in range(end_pwm, start_pwm, 0 -step):
+                tlc5947[pin] = pwm
+                # Again be sure to call write if you disabled auto_write.
+                #tlc5947.write()
+
+#----------
+# Choose here which function to try:
+#first_last()
+test_all_channels(16)