串口通信
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串口通信 |
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-- Lua serial communications library. -- -- Note: currently only works on Win32. -- -- The implementation uses alien ( http://alien.luaforge.net/ ). -- -- Warning: not extensively tested. -- -- Possible improvements: -- - decide more consistently when to raise or return on error -- (io.open/fh:read/fh:write return, but Lua -- Programming Gems, p.137 suggests we perhaps -- should raise) -- - add close() method on file handle, possibly -- via __gc on newproxy() so that it closes upon -- garbage collection -- -- D.Manura. 2008-07 -- S.Slobodov, 2009-01: fixed alien interface, fixed a typo, -- added COM10 and up, made non-blocking -- D.Manura, 2009-01: add close(); improve exception safety some -- S.Slobodov, 2009-01: added routines to set DTR and RTS and to query CTS, plus unbuffered transmission -- Licensed under the same terms as Lua itself (MIT license). -- Please post patches and improvements. local M = {} local alien = require "alien" -- win32 values for CreateFile local GENERIC_READ = 0x80000000 local GENERIC_WRITE = 0x40000000 local OPEN_EXISTING = 3 -- win32 parity values local EVENPARITY = 2 local MARKPARITY = 3 local NOPARITY = 0 local ODDPARITY = 1 local SPACEPARITY = 4 -- win32 stop bit values local ONESTOPBIT = 0 local ONE5STOPBITS = 1 local TWOSTOPBITS = 2 -- maps parity name to win32 parity value local parity_to_win32 = { even = EVENPARITY, mark = MARKPARITY, none = NOPARITY, odd = ODDPARITY, space = SPACEPARITY } -- maps stop bits to win32 stop bits value local stopbits_to_win32 = { [1] = ONESTOPBIT, [1.5] = ONE5STOPBITS, [2] = TWOSTOPBITS } local kernel32 = alien.load"kernel32.dll" -- bitwise operators -- based on http://ricilake.blogspot.com/2007/10/iterating-bits-in-lua.html -- 1-based indexing local function bit(p) return 2 ^ (p - 1) end local function hasbit(x, p) return x % (p + p) >= p end local function setbit(x, p) return hasbit(x, p) and x or x + p end local function clearbit(x, p) return hasbit(x, p) and x - p or x end local function changebit(x, p, b) return b and setbit(x,p) or clearbit(x,p) end local function get_last_error() local FORMAT_MESSAGE_ALLOCATE_BUFFER = 0x00000100 local FORMAT_MESSAGE_FROM_SYSTEM = 0x00001000 local FORMAT_MESSAGE_IGNORE_INSERTS = 0x00000200 local LANG_NEUTRAL = 0x00 local SUBLANG_DEFAULT = 0x01 local function MAKELANGID(p, s) return s * 2^10 + p end -- C function declarations local FormatMessage = assert(kernel32.FormatMessageA) FormatMessage:types{ret ='int', abi = 'stdcall', 'int', 'pointer', 'int', 'int', 'pointer', 'int', 'pointer'} local GetLastError = assert(kernel32.GetLastError) GetLastError:types{ret = 'int', abi = 'stdcall'} local LocalFree = assert(kernel32.LocalFree) LocalFree:types{ret = 'pointer', abi = 'stdcall', 'pointer'} local buf = alien.buffer(4) buf:set(0, buf2, 'pointer') local ret = FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER + FORMAT_MESSAGE_FROM_SYSTEM + FORMAT_MESSAGE_IGNORE_INSERTS, nil, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buf, -- ref: msg_buf, 0, nil ) if ret == 0 then return "Unknown error." end local msg = alien.tostring(buf:get(1,'pointer')) LocalFree(buf:get(1, 'pointer')) return msg end local function config(h, t) local speed = t.speed local databits = t.databits local stopbits = t.stopbits local parity = t.parity local handshake = t.handshake assert(stopbits_to_win32[stopbits]) assert(parity_to_win32[parity]) assert(databits == 5 or databits == 6 or databits == 7 or databits == 8) assert(type(speed) == 'number' and speed > 0) -- C function declarations local GetCommState = kernel32.GetCommState GetCommState:types{ret = "int", abi = 'stdcall', "pointer", "pointer"} local SetCommState = assert(kernel32.SetCommState) SetCommState:types{ret = "int", abi = 'stdcall', "pointer", "pointer"} local SetCommTimeouts = assert(kernel32.SetCommTimeouts) SetCommTimeouts:types{ret = "int", abi = 'stdcall', "pointer", "pointer"} local buf = alien.buffer(4*3 + 3*2 + 3*1 + 5*3 + 2*1) GetCommState(h, buf) local offset_DCBlength = 1 local offset_BaudRate = 1 + 1*4 local offset_flags = 1 + 2*4 local offset_XonLim = 1 + 3*4 + 1*2 local offset_XoffLim = 1 + 3*4 + 2*2 local offset_ByteSize = 1 + 3*4 + 3*2 local offset_Parity = 1 + 3*4 + 3*2 + 1 local offset_StopBits = 1 + 3*4 + 3*2 + 2 local offset_XonChar = 1 + 3*4 + 3*2 + 3 local offset_XoffChar = 1 + 3*4 + 3*2 + 4 local offset_ErrorChar = 1 + 3*4 + 3*2 + 5 local offset_EofChar = 1 + 3*4 + 3*2 + 6 local offset_EvtChar = 1 + 3*4 + 3*2 + 7 buf:set(offset_BaudRate, speed, 'int') local bits = buf:get(offset_flags, 'int') bits = changebit(bits, bit(1), true) -- fBinary bits = changebit(bits, bit(2), parity ~= 'none') -- fParity bits = changebit(bits, bit(3), handshake == 'hardware') -- fOutxCtsFlow bits = changebit(bits, bit(4), false) -- fOutxDsrFlow (ok?) bits = changebit(bits, bit(5), false) -- fDtrControl[1] (ok?) bits = changebit(bits, bit(6), false) -- fDtrControl[2] (ok?) bits = changebit(bits, bit(7), false) -- fDsrSensitivity (ok?) bits = changebit(bits, bit(8), false) -- fTXContinueOnXoff (ok?) bits = changebit(bits, bit(9), handshake == 'xon/xoff') -- fOutX bits = changebit(bits, bit(10), handshake == 'xon/xoff') -- fInX bits = changebit(bits, bit(11), false) -- fErrorChar (ok?) bits = changebit(bits, bit(12), false) -- fNull (ok?) bits = changebit(bits, bit(13), false) -- fRtsControl [1] bits = changebit(bits, bit(14), handshake == 'xon/xoff') -- fRtsControl [2] bits = changebit(bits, bit(15), false) -- fAbortOnError (ok?) buf:set(offset_flags, bits, 'int') buf:set(offset_ByteSize, databits, 'byte') buf:set(offset_Parity, parity_to_win32[parity], 'byte') buf:set(offset_StopBits, stopbits_to_win32[stopbits], 'byte') SetCommState(h, buf) -- timeout on receive immediately if no data pending -- (so that you have a chance to do bigger an better things) -- http://msdn.microsoft.com/en-us/library/aa363437(VS.85).aspx local buf = alien.buffer(4*5) -- _COMMTIMEOUTS: buf:set(1, -1, "int") -- ReadIntervalTimeout buf:set(1+4*1, 0, "int") -- ReadTotalTimeoutMultiplier buf:set(1+4*2, 0, "int") -- ReadTotalTimeoutConstant buf:set(1+4*3, 0, "int") -- WriteTotalTimeoutMultiplier buf:set(1+4*4, 0, "int") -- WriteTotalTimeoutConstant SetCommTimeouts(h, buf) end local CloseHandle local function open(t) local port = t.port assert(type(port) == 'string' and port:match('^COM[0-9]+$'), 'invalid port name '..port..'; expecting e.g. "COM1"') local portNum = port:match("^COM([0-9]+)") if portNum+0 >= 10 then port = "\\\\.\\"..port end -- C function declarations local CreateFile = assert(kernel32.CreateFileA) CreateFile:types{ret = "pointer", abi = 'stdcall', "string", "int", "int", "pointer", "int", "int", "pointer"} CloseHandle = assert(kernel32.CloseHandle) CloseHandle:types{ret = 'int', abi = 'stdcall', "pointer"} local n = (GENERIC_READ + GENERIC_WRITE) - 2^32 + 1 local h = CreateFile(port, n, 0, nil, OPEN_EXISTING, 0, nil) -- convert handle to int local tmp = alien.buffer(4) tmp:set(1, h, 'pointer') local hnum = tmp:get(1, 'int') if hnum == -1 then return nil, get_last_error() end local ok, msg = pcall(config, h, t) if not ok then CloseHandle(h) return nil, msg end return h end M.open = open local function close(h) CloseHandle(h) end M.close = close local function send(h, s) local WriteFile = assert(kernel32.WriteFile) WriteFile:types{ret="int", abi = 'stdcall', "pointer", "string", "int", "ref int", "pointer"} local bytes_written_buf = alien.buffer(4) local ret, nwritten = WriteFile(h, s, #s, 0, nil ) if ret == 0 or nwritten ~= #s then error("failed write: " .. get_last_error()) end end M.send = send local function receive(h) -- C function declarations local ReadFile = assert(kernel32.ReadFile) ReadFile:types{ ret = 'int', abi = 'stdcall', "pointer", "ref char", "int", "ref int", "pointer"} local ret, char, nread = ReadFile(h, buffer_buf, 1, 0, nil ) if ret == 0 then error("failed read: " .. get_last_error()) end if char < 0 then char = char+256 end -- avoid negatives return nread == 1 and string.char(char) or nil end M.receive = receive local function receive_all(h) local s = "" while 1 do local c = receive(h) if c then s = s .. c else return s end end end M.receive_all = receive_all local buf = "" local function async_read_until(h, char) while 1 do local c = receive(h) if c then buf = buf .. c if c == char then local s = buf buf = "" return s end else return end end end local function SetDTR(h, set) local EscapeCommFunction = assert(kernel32.EscapeCommFunction) EscapeCommFunction:types{ret="int", abi = 'stdcall', "pointer", "int"} if set then EscapeCommFunction(h, SETDTR) else EscapeCommFunction(h, CLRDTR) end end M.SetDTR = SetDTR local function SetRTS(h, set) local EscapeCommFunction = assert(kernel32.EscapeCommFunction) EscapeCommFunction:types{ret="int", abi = 'stdcall', "pointer", "int"} if set then EscapeCommFunction(h, SETRTS) else EscapeCommFunction(h, CLRRTS) end end M.SetRTS = SetRTS local function GetCTS(h) local GetCommModemStatus = assert(kernel32.GetCommModemStatus) GetCommModemStatus:types{ret = "int", abi = "stdcall", "pointer", "ref int"} local _, CTS = GetCommModemStatus(h, 0) return CTS == CTS_ON end M.GetCTS = GetCTS local function TransmitChar(h, c) local TransmitCommChar = assert(kernel32.TransmitCommChar) TransmitCommChar:types{ret="int", abi = 'stdcall', "pointer", "int"} if not TransmitCommChar(h, c) then return nil, get_last_error() else return true end end M.TransmitChar = TransmitChar return M
以下是一个示例代码，它将串口和本地套接字端口之间的所有流量重定向。它对我有用，但你的结果可能会有所不同。从 Lua 命令提示符运行。外部 while 循环是为了允许 ip 客户端在不重新启动脚本的情况下重复重新连接。
local s=require "socket" local com=require "serial" if arg[1] == nil then print("Usage: "..arg[0].." <socket port> ".. "[<com port> [<speed> [<databits> [<parity> [<stopbits>]]]]]") print("Example: "..arg[0].." 10000 COM1 38400 8 none 1") return end local port = tonumber(arg[1]) or 10000 local comport = arg[2] or "COM1" local speed = tonumber(arg[3]) or 38400 local databits = tonumber(arg[4]) or 8 local parity = arg[5] or "none" local stopbits = tonumber(arg[6]) or 1 local sp, errmsg = assert(com.open{port=comport, speed=speed, databits=databits, stopbits=stopbits, parity=parity}) while true do local server = assert(s.bind("127.0.0.1", port )) print("waiting for connection on port", port) local client = assert(server:accept()) print("connected") client:settimeout(0.1) while true do local data, errmsg, partial = client:receive() if errmsg == "closed" then print("connection closed") client:close() server:close() break elseif errmsg == "timeout" then data = partial elseif errmsg then error(errmsg) end if data and data ~= "" then for i = 1, #data do local c = data:sub(i,i) com.send(sp, c) end end data = com.receive_all(sp) if data and data ~= "" then client:send(data) end end end
-- Petr �tetiar <[email protected]>
