NodeMCU固件- i2C/SPI/Uart/1-wire控制

參考連結: NodeMCU API指令


https://github.com/nodemcu/nodemcu-firmware/tree/84a9ab35a8eb9b4ae2229bba7b2626c2a285818d/app/driver

I2C

    id=0
    sda=1
    scl=2

    -- initialize i2c, set pin1 as sda, set pin2 as scl
    i2c.setup(id,sda,scl,i2c.SLOW)

    -- user defined function: read from reg_addr content of dev_addr
    function read_reg(dev_addr, reg_addr)
      i2c.start(id)
      i2c.address(id, dev_addr ,i2c.TRANSMITTER)
      i2c.write(id,reg_addr)
      i2c.stop(id)
      i2c.start(id)
      i2c.address(id, dev_addr,i2c.RECEIVER)
      c=i2c.read(id,1)
      i2c.stop(id)
      return c
    end

    -- get content of register 0xAA of device 0x77
    reg = read_reg(0x77, 0xAA)
    print(string.byte(reg))

UART

    -- when 4 chars is received.
    uart.on("data", 4, 
      function(data)
        print("receive from uart:", data)
        if data=="quit" then 
          uart.on("data") 
        end        
    end, 0)
    -- when '\r' is received.
    uart.on("data", "\r", 
      function(data)
        print("receive from uart:", data)
        if data=="quit\r" then 
          uart.on("data") 
        end        
    end, 0)

1-Wire

-- 18b20 Example
pin = 9
ow.setup(pin)
count = 0
repeat
  count = count + 1
  addr = ow.reset_search(pin)
  addr = ow.search(pin)
  tmr.wdclr()
until((addr ~= nil) or (count > 100))
if (addr == nil) then
  print("No more addresses.")
else
  print(addr:byte(1,8))
  crc = ow.crc8(string.sub(addr,1,7))
  if (crc == addr:byte(8)) then
    if ((addr:byte(1) == 0x10) or (addr:byte(1) == 0x28)) then
      print("Device is a DS18S20 family device.")
        repeat
          ow.reset(pin)
          ow.select(pin, addr)
          ow.write(pin, 0x44, 1)
          tmr.delay(1000000)
          present = ow.reset(pin)
          ow.select(pin, addr)
          ow.write(pin,0xBE,1)
          print("P="..present)  
          data = nil
          data = string.char(ow.read(pin))
          for i = 1, 8 do
            data = data .. string.char(ow.read(pin))
          end
          print(data:byte(1,9))
          crc = ow.crc8(string.sub(data,1,8))
          print("CRC="..crc)
          if (crc == data:byte(9)) then
             t = (data:byte(1) + data:byte(2) * 256) * 625
             t1 = t / 10000
             t2 = t % 10000
             print("Temperature="..t1.."."..t2.."Centigrade")
          end                   
          tmr.wdclr()
        until false
    else
      print("Device family is not recognized.")
    end
  else
    print("CRC is not valid!")
  end
end

SPI
id: spi id number.
mode: MASTER or SLAVE(not supported yet).
cpol: CPOL_LOW or CPOL_HIGH, clock polarity.
cpha: CPHA_HIGH or CPHA_LOW, clock phase.
databits: DATABITS_8 or DATABITS_16.
clock: spi clock (not supported yet).