add the cascaded matrix support

adafruit_max7219/max7219.py

@@ -1,5 +1,6 @@
 # SPDX-FileCopyrightText: 2016 Philip R. Moyer  for Adafruit Industries
 # SPDX-FileCopyrightText: 2016 Radomir Dopieralski for Adafruit Industries
+# SPDX-FileCopyrightText: 2021 bluejazzCHN for Adafruit Industries
 #
 # SPDX-License-Identifier: MIT
 
@@ -24,15 +25,16 @@
 --------------------
 **Hardware:**
 
-* Adafruit `MAX7219CNG LED Matrix/Digit Display Driver -
+* `Adafruit MAX7219CNG LED Matrix/Digit Display Driver -
   MAX7219 <https://www.adafruit.com/product/453>`_ (Product ID: 453)
 
 **Software and Dependencies:**
 
 * Adafruit CircuitPython firmware for the ESP8622 and M0-based boards:
   https://github.com/adafruit/circuitpython/releases
 
-* Adafruit's Bus Device library: https://github.com/adafruit/Adafruit_CircuitPython_BusDevice
+* Adafruit's Bus Device library:
+  https://github.com/adafruit/Adafruit_CircuitPython_BusDevice
 
 **Notes:**
 #.  Datasheet: https://cdn-shop.adafruit.com/datasheets/MAX7219.pdf
@@ -54,7 +56,6 @@
 class MAX7219:
     """
     MAX2719 - driver for displays based on max719 chip_select
-
     :param int width: the number of pixels wide
     :param int height: the number of pixels high
     :param object spi: an spi busio or spi bitbangio object
@@ -89,32 +90,31 @@ def init_display(self):
     def brightness(self, value):
         """
         Controls the brightness of the display.
-
         :param int value: 0->15 dimmest to brightest
         """
         if not 0 <= value <= 15:
             raise ValueError("Brightness out of range")
         self.write_cmd(_INTENSITY, value)
 
-    def show(self):
+    def show(self, number=1, t_num=1):
         """
         Updates the display.
+        :param int number: which one is in the cascaded matrixs, default is 1.
+        :param int t_num: total number of cascaded Matrixs,default is 1.
         """
         for ypos in range(8):
-            self.write_cmd(_DIGIT0 + ypos, self._buffer[ypos])
+            self.write_cmd(_DIGIT0 + ypos, self._buffer[ypos], number, t_num)
 
     def fill(self, bit_value):
         """
         Fill the display buffer.
-
         :param int bit_value: value > 0 set the buffer bit, else clears the buffer bit
         """
         self.framebuf.fill(bit_value)
 
     def pixel(self, xpos, ypos, bit_value=None):
         """
         Set one buffer bit
-
         :param xpos: x position to set bit
         :param ypos: y position to set bit
         :param int bit_value: value > 0 sets the buffer bit, else clears the buffer bit
@@ -126,10 +126,29 @@ def scroll(self, delta_x, delta_y):
         """Srcolls the display using delta_x,delta_y."""
         self.framebuf.scroll(delta_x, delta_y)
 
-    def write_cmd(self, cmd, data):
+    def write_cmd(self, cmd, data, number=1, t_num=1):
         # pylint: disable=no-member
-        """Writes a command to spi device."""
+        """Writes a command to spi device.
+        :param int number: whichi one is in the cascaded matrixs, default is 1.
+        :param int t_num: total number of cascaded Matrixs,default is 1.
+        """
         # print('cmd {} data {}'.format(cmd,data))
         self._chip_select.value = False
+
+        # send Noop to ones behind number Matrix
         with self._spi_device as my_spi_device:
+            for i in range(number, t_num):
+                my_spi_device.write(bytearray([0, 0]))
+
             my_spi_device.write(bytearray([cmd, data]))
+
+            # send Noop to all before number, if you want to know why, please ref to MAX7219.pdf.
+            for _ in range(0, number - 1):
+                my_spi_device.write(bytearray([0, 0]))
+
+    def rotation(self, direction):
+        """
+        Set display direction
+        :param direction:set int to change display direction, value 0 (default), 1, 2, 3
+        """
+        self.framebuf.rotation = direction

examples/max7219_cascade.py

@@ -0,0 +1,42 @@
+# SPDX-FileCopyrightText: 2021 bluejazzCHN for Adafruit Industries
+# SPDX-License-Identifier: MIT
+
+import time
+import random
+from board import TX, RX, A2
+import busio
+import digitalio
+from adafruit_max7219 import matrices
+
+clk = RX
+din = TX
+cs = digitalio.DigitalInOut(A2)
+
+spi = busio.SPI(clk, MOSI=din)
+display = matrices.Matrix8x8(spi, cs)
+
+while True:
+    display.clear_all()
+    s = "Hello, World!"
+
+    # Demo One: cascaded matrix with two max7219
+    # show random char in string s on the the first of cascaded matrixs.
+    # show scroll string s on the second of cascaded matrixs.
+    display.text(s[random.randint(0, len(s) - 1)], 0, 0)
+    display.show(1, 2)
+
+    for c in range(len(s) * 8):
+        display.fill(0)
+        display.text(s, -c, 0)
+        display.show(2, 2)
+        time.sleep(0.25)
+
+    # Demo two: scroll string s on the cascaded matrix with two max7219
+    for c in range(len(s) * 8):
+        display.fill(0)
+        display.text(s, -c, 0)
+        display.show(1, 2)
+        display.fill(0)
+        display.text(s, -c + 8, 0)
+        display.show(2, 2)
+        time.sleep(0.25)