Soft Serial UART hang after reconnect

acjacques · Joined: 24 Feb 2019 Posts: 13 Location: Rio de Janeiro

My 328p with bellow code works fine to receiving the serial input but if there are a momentary disconnection from this input the processor hangs then only reconnecting after a reset.

I have tryed the timeout but it seems does not work.

Obs. The input pin PORTC.1 have a 1k series resistor. I dont believe this could matter in this issue.

Thanks for any help.

'============================code==================

$regfile = "m328pdef.dat"
$crystal = 16000000
$baud = 115200
$hwstack = 32
$swstack = 16
$framesize = 50
$lib "serin.lib"

Dim serin_timeout as long
Dim S As String * 8
Dim I As Word

do

serin_timeout = 50000
Serin S , 1 , PortC , 1 , 9600 , 0 , 8 , 1 'testada a saida digital no pino analogo
I = Val(s) 'isola só os numeros da string transformando para numerico
S = Str(i) 'numérico de volta para string
S = Format(s , "0000") 'formata a string
S = S + " mm" 'soma a string
Print S
Waitms 50

loop

(BASCOM-AVR version : 2.0.8.2 )

Evert :-) · Joined: 18 Feb 2005 Posts: 2108

The serin is set as input, so if the signal is momentary disconnected then this input pickup noise etc. and will do strange things.
Try 10K pulldown resistor to hold the serin in known active state when the signal disconnect.

EDC · Joined: 26 Mar 2014 Posts: 677

Mega328P are armed with PCINT on the every pin. You can start timer for "one or more byte long for the given baudrate" and somehow handle the timeout.