add lcd display

Author: iitzex

README.md

@@ -35,5 +35,7 @@ stepper.py : use 28BYJ-48 5V DC stepper
 sonic.py : use HC-SR04 to measure distance
         Pin:D5, D6
 
+lcd.py : show message on 2 line LCD Display
+        Pin:D1, D2, D5, D6, D7, D8
 
 ```

lcd.py

@@ -0,0 +1,71 @@
+from pyb import Pin
+from time import sleep_ms, sleep_us, ticks_us
+from machine import Timer
+
+RS = Pin(5, Pin.OUT)
+E = Pin(4, Pin.OUT)
+D4 = Pin(14, Pin.OUT)
+D5 = Pin(12, Pin.OUT)
+D6 = Pin(13, Pin.OUT)
+D7 = Pin(15, Pin.OUT)
+
+# Define some device constants
+WIDTH = 16 # Maximum characters per line
+CHR = True
+CMD = False
+LINE1 = 0x80 # LCD RAM address for the 1st line
+LINE2 = 0xC0 # LCD RAM address for the 2nd line
+DELAY = 15 #ms
+
+def lcd_enable():
+    E.value(1)
+    sleep_ms(DELAY)
+    E.value(0)
+    sleep_ms(DELAY)
+
+def lcd_byte(bits, Mode=True): #CMD:False, CHR=True
+    E.value(0)
+    RS.value(1 if Mode else 0)
+    D7.value(1 if (0x80 & bits) else 0)
+    D6.value(1 if (0x40 & bits) else 0)
+    D5.value(1 if (0x20 & bits) else 0)
+    D4.value(1 if (0x10 & bits) else 0)
+    # print("%s %02x %d %d %d %d" % (str(chr), bits,D4.value(), D5.value(), D6.value(), D7.value()))
+    lcd_enable()
+    #
+    E.value(0)
+    RS.value(1 if Mode else 0)
+    D7.value(1 if (0x08 & bits) else 0)
+    D6.value(1 if (0x04 & bits) else 0)
+    D5.value(1 if (0x02 & bits) else 0)
+    D4.value(1 if (0x01 & bits) else 0)
+    # print("%d %d %d %d" % (D4.value(), D5.value(), D6.value(), D7.value()))
+    lcd_enable()
+
+def lcd_init():
+    sleep_ms(DELAY)
+    lcd_byte(0x33, CMD)
+    lcd_byte(0x32, CMD)
+    lcd_byte(0x06, CMD)
+    lcd_byte(0x0C, CMD)
+    lcd_byte(0x28, CMD)
+    lcd_clear()
+
+def lcd_clear():
+    lcd_byte(0x01, CMD)
+    lcd_byte(LINE1, CMD)
+
+def lcd_str(msg, line=LINE1):
+    lcd_byte(line, CMD)
+    if len(msg) > WIDTH:
+        print("over length")
+        return
+    for i in range(len(msg)):
+        lcd_byte(ord(msg[i]), CHR)
+
+if __name__ == '__main__':
+    lcd_init()
+    lcd_str("Hello World!", LINE1)
+    lcd_str("2nd line.", LINE2)
+
+#