Haskell:串口接收数据打印不正确

Question

我正在尝试从我的 Arduino Serial.println("No Format"); 接收数据。当我打开 arduino-serial-monitor 时，我可以看到我想要的输出。

No Format
No Format
...

我用 serialport package.但是在ghci上打印的输出是：

*Main> main
"\r\nNo Forma"
"t\r\nNo Form"
"at\r\nNo For"
"mat\r\nNo Fo"
"rmat\r\nNo F"
"ormat\r\nNo "
"Format\r\nNo"
" Format\r\nN"
"o Format\r\n"
...
...
"\nNo"
" For"
"mat\r"
"\nNo "
"Form"
"at\r\n"
....

Haskell:

import qualified Data.ByteString.Char8 as B
import System.Hardware.Serialport
import System.IO
import Control.Monad

main :: IO ()
main = forever $ do
  let port = "/dev/ttyACM0"
  s <- openSerial port SerialPortSettings { commSpeed = CS9600,
                                            bitsPerWord = 8,
                                            stopb = One,
                                            parity = NoParity,
                                            flowControl = NoFlowControl,
                                            timeout = 10 }
  recv s 10 >>= print
  closeSerial s

Arduino:

void setup() {
  Serial.begin(9600);
}

void loop() {
  Serial.println("No Format");
}

任何帮助都会很棒。谢谢。

Answer 1

您可以只接收字符，直到接收到“\n”字符。也许是这样的：

import Control.Monad (forever)
import Control.Applicative ((<$>))
import Data.ByteString.Char8 (unpack)
import System.Hardware.Serialport (SerialPort, openSerial, recv)

-- Read a character from the serial port.
receive :: SerialPort -> IO String
receive sp = fmap unpack (recv sp 1)

-- Read a line, ending with '\n'.
readLine :: SerialPort -> IO String
readLine sp = readLineRec sp [] 

-- Recursive function to read a line from the serial port.
readLineRec :: SerialPort -> String -> IO String
readLineRec sp [] = receive sp >>= readLineRec sp 
readLineRec sp chars
    | last chars == '\n' = return chars
    | otherwise = (chars ++) <$> receive sp >>= readLineRec sp

main = do
    let port = "/dev/ttyACM0"
    s <- openSerial port SerialPortSettings { commSpeed = CS9600,
                                        bitsPerWord = 8,
                                        stopb = One,
                                        parity = NoParity,
                                        flowControl = NoFlowControl,
                                        timeout = 10 }
    forever $ do
        line <- readLine s
        print line

还有改进的余地，但很管用！

Answer 2

使用 B.putStr 而不是 print 解决了问题。感谢@pat.

Haskell:串口接收数据打印不正确

Haskell: Serial received data not printed correctly

haskell

serial-port

arduino