Serial Port not writing

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John
John on 7 Aug 2014
Answered: John on 7 Aug 2014
In Matlab 2014a (on ubuntu 12.04, 64-bit), a serial port that I'm writing to doesn't actually output anything from the FTDI-RS232 cable. As seen by a scope, no bits are being sent, the line remains high. There is no matlab error, and "ValuesSent" increments as it should every time i "transmit". However, TransferStatus remains idle all the time.
I can read data IN to matlab over another serial port just fine, but i'm not trying to write to that one. Thoughts on why a port wouldn't be writing? I have given the appropriate read-write privileges to the port, and if i didn't I'd get a port-open error. No flow control is needed.
s = serial('/dev/ttyUSB2','BaudRate',115200,'DataBits',8, 'StopBits', 1);
fopen(s);
s.FlowControl = 'none';
fprintf(s, '%s', 'asbc');
---------------------
get(s) gives:
ByteOrder = littleEndian
BytesAvailable = 0
BytesAvailableFcn =
BytesAvailableFcnCount = 48
BytesAvailableFcnMode = terminator
BytesToOutput = 0
ErrorFcn =
InputBufferSize = 512
Name = Serial-/dev/ttyUSB2
ObjectVisibility = on
OutputBufferSize = 512
OutputEmptyFcn =
RecordDetail = compact
RecordMode = overwrite
RecordName = record.txt
RecordStatus = off
Status = open
Tag =
Timeout = 1
TimerFcn =
TimerPeriod = 1
TransferStatus = idle
Type = serial
UserData = []
ValuesReceived = 0
ValuesSent = 260
SERIAL specific properties:
BaudRate = 115200
BreakInterruptFcn =
DataBits = 8
DataTerminalReady = on
FlowControl = none
Parity = none
PinStatus = [1x1 struct]
PinStatusFcn =
Port = /dev/ttyUSB2
ReadAsyncMode = continuous
RequestToSend = on
StopBits = 1
Terminator = CR/LF

Answers (2)

John
John on 7 Aug 2014
Huh, turns out it was a bad usb to serial cable. Lost hours on this, but it does work now.

alican kara
alican kara on 14 Jul 2020

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