Problem with TCP to UART bridge coding
Posted: Wed Jul 22, 2015 6:27 amHello,
I was interested in creating a simplified ESP8255 nodemcu UART<>TCP transparent bridge with the minimum of LUA code. However, I found an issue when transferring bytes between the TCP server connection and the UART. It seems to corrupt data transfer whenever a 0xFF byte is encountered. My code is shown below
Sending bytes from TCP Server to UART (shown in hex)
TCP byte send: 11 22 33 44 55 FF 66 77
UART byte receive: 11 22 33 44 55 FF FF 66 77 <-- two FF received, only one expected
This test was repeated with different serial terminal programs to exclude data corruption by an external source. Also, this issue is transfer rate independent, as my testing was done by manually sending bytes (hence no buffering shown).
Can anyone see if there is an issue with my code that would directly cause this problem?
My environment:
Regards,
Andrew.
I was interested in creating a simplified ESP8255 nodemcu UART<>TCP transparent bridge with the minimum of LUA code. However, I found an issue when transferring bytes between the TCP server connection and the UART. It seems to corrupt data transfer whenever a 0xFF byte is encountered. My code is shown below
Code: Select all
-- init.lua
abort = false
wifi.setmode(wifi.STATION)
--modify according your wireless router settings
wifi.sta.config("ssid","password")
wifi.sta.connect()
function startup()
tmr.stop(2)
if abort == true then
print('startup aborted')
return
end
uart.setup(0, 9600, 8, 0, 1, 1)
dofile("bridge.lua")
end
abort = false
tmr.alarm(1, 1000, 1, function()
if wifi.sta.getip()== nil then
print("IP unavailable, Waiting...")
else
tmr.stop(1)
print("Config done, IP is "..wifi.sta.getip())
tmr.alarm(2, 5000, 0, startup)
end
end)
Code: Select all
-- Bridge.lua
-- Based loosely on code by Thorsten von Eicken, esp8266-lua-bridge , (C) 2015
uartConn = nil -- current connection that uart input goes to
ser2net = net.createServer(net.TCP, 28800)
ser2net:listen(23, function(conn)
if uartConn then
uartConn:close()
else
uartConn = conn
end
conn:on("sent",function(conn)
collectgarbage()
end)
-- Disconnection
conn:on("disconnection", function(conn)
uartConn:close()
collectgarbage()
end)
-- Reconnection
conn:on("reconnection", function(conn)
if uartConn then
uartConn:close()
else
uartConn = conn
end
end)
-- UART receive, TCP send
uart.on("data", 0, function(data)
conn:send(data)
end, 0)
-- TCP receive, UART send
conn:on("receive", function(conn, data)
uart.write(0, data)
end)
end)
Sending bytes from TCP Server to UART (shown in hex)
TCP byte send: 11 22 33 44 55 FF 66 77
UART byte receive: 11 22 33 44 55 FF FF 66 77 <-- two FF received, only one expected
This test was repeated with different serial terminal programs to exclude data corruption by an external source. Also, this issue is transfer rate independent, as my testing was done by manually sending bytes (hence no buffering shown).
Can anyone see if there is an issue with my code that would directly cause this problem?
My environment:
- nodemcu_integer_0.9.6-dev_20150406
Esplorer V0.2.0-rc2
ESP8266 ESP-12 module
TTL to UART interface
3.3V power supply
Windows Serial terminal programs: Compuphase Termite, HW Hercules, Bray terminal, and bespoke MFC C++ application
Regards,
Andrew.