from machine import Pin
from time import sleep, sleep_ms

# 定义LCD数据引脚
D7 = Pin(0, Pin.OUT)
D6 = Pin(1, Pin.OUT)
D5 = Pin(2, Pin.OUT)
D4 = Pin(3, Pin.OUT)
D3 = Pin(4, Pin.OUT)
D2 = Pin(5, Pin.OUT)
D1 = Pin(6, Pin.OUT)
D0 = Pin(7, Pin.OUT)
port_d8 = [D0, D1, D2, D3, D4, D5, D6, D7]

# 定义LCD控制引脚
RS = Pin(13, Pin.OUT)
RW = Pin(12, Pin.OUT)
EN = Pin(11, Pin.OUT)



# 向LCD发送命令
def write_cmd(cmd):
  
   EN.value(0)
   sleep_ms(1)
   RS.value(0)  # 选择命令寄存器
   x = cmd
   for i in range(8):
       bit = x & 0x01
       port_d8[i].value(bit)
       x = x >> 0x01
   sleep_ms(1)
   EN.value(1)  # 使能脉冲
   sleep_ms(1)
   EN.value(0)

# 初始化LCD
def lcd_init():
   write_cmd(0x38)  # 8位数据接口，两行显示，5x7点阵
   write_cmd(0x08)  # 关闭显示
   write_cmd(0x01)  # 清屏
   write_cmd(0x06)  # 显示光标移动设置
   sleep_ms(5)
   write_cmd(0x0f)  # 打开显示，光标闪烁

# 向LCD发送数据
def write_data(data):
   EN.value(0)
   sleep_ms(1)
   RS.value(1)  # 选择数据寄存器
   x = data
   for i in range(8):
       bit = x & 0x01
       port_d8[i].value(bit)
       x = x >> 0x01
   sleep_ms(1)
   EN.value(1)  # 使能脉冲
   sleep_ms(1)
   EN.value(0)

# 在指定位置写一个字符
def write_ch(x, y, ch):
   if y == 0:
       write_cmd(0x80 + x)  # 第一行
   else:
       write_cmd(0xc0 + x)  # 第二行
   write_data(ord(ch))

# 在指定位置写一个字符串
def write_str(x, y, string):
   for i, char in enumerate(string):
       write_ch(x + i, y, char)

   
# 清屏
def lcd_clear():
   write_cmd(0x01)
   sleep_ms(5)

# 清除第二行
def clear_second_line():
   write_cmd(0xC0)  # 移动光标到第二行开始
   for _ in range(16):  # 假设第二行有16个字符
       write_data(0x20)  # 写空格清除字符

# 定义键盘行引脚
pin_r = [
   Pin(26, Pin.IN, Pin.PULL_DOWN),
   Pin(22, Pin.IN, Pin.PULL_DOWN),
   Pin(21, Pin.IN, Pin.PULL_DOWN),
   Pin(20, Pin.IN, Pin.PULL_DOWN)
]

# 定义键盘列引脚
pin_c = [
   Pin(19, Pin.OUT),
   Pin(18, Pin.OUT),
   Pin(17, Pin.OUT),
   Pin(16, Pin.OUT)
]

# 定义键盘按键映射
key_n = [
   ['1', '2', '3', '+'],
   ['4', '5', '6', '-'],
   ['7', '8', '9', '*'],
   ['C', '0', '=', '/']
]

# 扫描键盘并返回按下的按键
def key_s():
   for i in range(4):
       pin_c[i].value(1)
       for j in range(4):
           if pin_r[j].value():
               sleep_ms(10)
               if pin_r[j].value():
                   if key_n[j][i] == 'C':
                       clear_second_line()
                       return None
                   else:
                       return key_n[j][i]
       pin_c[i].value(0)
   return None

# 计算表达式
def calculate(expression):
   try:
       return str(eval(expression))
   except:
       return "Error"

if __name__ == "__main__":
   sleep_ms(15)
   lcd_init()
   write_str(0, 0, "SimpleCalculator")
   write_str(0, 1, "    huang yu")
   expression = ""
   while True:
       k = key_s()
       if k is not None:
           if k == 'C':
               clear_second_line()
               expression = ""
           elif k == '=':
               result = calculate(expression)
               clear_second_line()
               write_str(0, 1, result)
               expression = ""
           else:
               expression += k
               write_ch(len(expression) - 1, 1, k)
       sleep_ms(75)