examples: add test for epaper 2in13_v2 displays

This commits adds a short example for 2in13v2 displays.
Example is based on the use of framebuffer.

Signed-off-by: Pierre-Yves Kerbrat <pykerbrat@gmail.com>

examples/2in13v2-hello-world/test.py

@@ -0,0 +1,69 @@
+import epaper2in13v2
+from machine import Pin, SPI
+from time import sleep_ms
+
+sck=Pin(14)
+miso=Pin(12)
+mosi=Pin(13)
+cs=Pin(15)
+hsspi = SPI(1, baudrate=4000000, polarity=0, phase=0)
+dc = Pin(2)
+rst = Pin(4)
+busy = Pin(10)
+
+e = epaper2in13v2.EPD(hsspi, cs, dc, rst, busy)
+e.init(e.FULL_UPDATE)
+
+h = 250
+w = 122
+x = 0
+y = 0
+
+# --------------------
+
+import framebuf
+buf = bytearray(w * h // 8)
+fb = framebuf.FrameBuffer(buf, w, h, framebuf.MONO_HLSB)
+black = 0
+white = 1
+fb.fill(white)
+fb.text('Hello World',20, 60, black)
+#fb.pixel(30, 10, black)
+#fb.hline(30, 30, 10, black)
+#fb.vline(30, 50, 10, black)
+#fb.line(30, 70, 40, 80, black)
+#fb.rect(30, 90, 10, 10, black)
+#fb.fill_rect(20, 0, 10, 10, black)
+#for row in range(0,37):
+#	fb.text(str(row),0,row*8,black)
+#fb.text('Line 36',0,288,black)
+#fb.text('text2',30, 110, black)
+
+fb.text('00', 0, 00, black)
+fb.text('20', 0, 20, black)
+fb.text('40', 0, 40, black)
+fb.text('50', 0, 50, black)
+fb.text('70', 0, 70, black)
+fb.text('80', 0, 80, black)
+fb.text('100', 0, 100, black)
+fb.text('120', 0, 120, black)
+fb.text('140', 0, 140, black)
+fb.text('110', 0, 110, black)
+fb.text('130', 0, 130, black)
+fb.text('150', 0, 150, black)
+fb.text('170', 0, 170, black)
+fb.text('190', 0, 190, black)
+fb.text('210', 0, 210, black)
+fb.text('230', 0, 230, black)
+fb.text('240', 0, 240, black)
+e.display(buf)
+
+e.sleep()
+print("Waiting 3s")
+sleep_ms(3000)
+print("Wake up")
+e.wakeup()
+fb.rect(30, 90, 10, 10, black)
+e.display(buf)
+e.sleep()
+