How to run the "screen" command from NSTask? - unix

I want to monitor a virtual COM port (Arduino RFID) on my Mac. I can run "screen /dev/tty.serialnumber" from the terminal, and it outputs the RFID serial number when I swipe it.
As soon as I try it from Xcode with an NSTask I get the following output.
Must be connected to a terminal.
Here's my code:
NSTask *cd = [[NSTask alloc] init];
[cd setLaunchPath:#"/usr/bin/screen"];
[cd setArguments:[NSArray arrayWithObjects:#"-L",#"/dev/tty.usbserial-A800509K",nil]];
NSPipe *pipe;
pipe = [NSPipe pipe];
[cd setStandardOutput: pipe];
[cd setStandardInput:[NSPipe pipe]];
NSFileHandle *file;
file = [pipe fileHandleForReading];
[cd launch];
NSData *data;
data = [file readDataToEndOfFile];
NSString *string;
string = [[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding];
NSLog (#"%#", string);
[cd waitUntilExit];
[cd release];

I think you'd better directly access the COM port, either by using the foundation libraries, or by using third party Obj-C libs (for example, https://github.com/pbosetti/PBSerialPort).
Also, if you want to monitor the COM port, you will have to set a thread reading the serial port, and updating a text area in the UI. Remember that secondary thread should update the UI via the method - (void)performSelector:(SEL)aSelector onThread:(NSThread *)thr withObject:(id)arg waitUntilDone:(BOOL)wait.

Related

decode register to 32bit float big endian in python code on raspberry pi 3B with python library pymodbus2.5.3

I'm trying to get the data stream of a sensor transmitter that uses the modbus rtu communication protocol on my raspberry pi 3B. I'm able to get the data with the pymodbus2.5.3 library.
For this I use this code:
from pymodbus.client.sync import ModbusSerialClient # Import the pymodbus library part for syncronous master (=client)
client = ModbusSerialClient(
method='rtu', #Modbus Modus = RTU = via USB & RS485
port='/dev/ttyUSB0', #Connected over ttyUSB0, not AMA0
baudrate=19200, #Baudrate was changed from 38400 to 19200
timeout=3, #
parity='N', #Parity = None
stopbits=2, #Bites was changed from 1 to 2
bytesize=8 #
)
if client.connect(): # Trying to connect to Modbus Server/Slave
#Reading from a holding register
res = client.read_holding_registers(address=100, count=8, unit=1) #Startregister = 100, Registers to be read = 8, Answer size = 1 byte
if not res.isError(): #If Registers don't show Error
print(res.registers) #Print content of registers
else:
print(res) #Print Error Message, for meaning look at (insert git hub)
else: #If not able to connect, do this
print('Cannot connect to the Transmitter M80 SM and Sensor InPro 5000i.')
print('Please check the following things:')
print('Does the RS485-to-USB Adapter have power? Which LEDs are active?')
print('Are the cables connected correctly?')
And get the following output:
[15872, 17996, 16828, 15728, 16283, 45436, 16355, 63231]
With the help of the Modbus Poll and Slave Programms I know that those results should decoded be:
[0.125268, --, 23.53, --, 1.21094, --, 1.77344, --]
To get to the right results I tried the command that the pymodbus github suggests .decode():
res.decode(word_order = little, byte_order = little, formatters = float64)
[I know that those aren't the needed options but I copied the suggested github code to check if it works.]
After putting the code segment into the code the changed part looks like this:
if not res.isError(): #If Registers don't show Error
res.decode(word_order = little, byte_order = little, formatters = float64)
print(res.registers) #Print content of registers
else:
print(res) #Print Error Message, for meaning look at (insert git hub)
When I run this code, I get the following output, that traces to the decoding segment:
NameError: name 'little' is not defined
After this, I imported also the pymodbus part translation. But it showed the same output.
How can I decode my incoming data?
You can use BinaryPayloadDecoder to help decoding your payload, here is a simplified example, change Endian.Big and Endian.Little if needed.
if client.connect(): # Trying to connect to Modbus Server/Slave
#Reading from a holding register
res = client.read_holding_registers(address=100, count=8, unit=1) #Startregister = 100, Registers to be read = 8, Answer size = 1 byte
# ====== added code start ======
decoder = BinaryPayloadDecoder.fromRegisters(res.registers, Endian.Little, wordorder=Endian.Little)
first_reading = decoder.decode_32bit_float()
second_reading = decoder.decode_32bit_float()
# ====== added code end ======
if not res.isError(): #If Registers don't show Error
print(res.registers) #Print content of registers
else:
print(res) #Print Error Message, for meaning look at (insert git hub)
Remember to import from pymodbus.payload import BinaryPayloadDecoder at top and add necessary exception handlers in your final code.
Reference document: https://pymodbus.readthedocs.io/en/latest/source/library/pymodbus.html#pymodbus.payload.BinaryPayloadDecoder

qt read data from serial port just after open by another program

I'm using Qt version 5.5.1 from windows 8.1.
When I run qtserialport terminal example,
program connects to port successfully, but does not receive any data.
But when I close this program and open Hercules_3-2-6 Application (rs232 terminal software), that application read data,
and after close Hercules_3-2-6 application and open terminal example again, this program works and reads data until restarting computer.
I repeat this process many times.
But terminal project does not receive any data after restarting system until port opens one time by Hercules_3-2-6 Application.
Specification of port:
Name: COM3,
Baud Rate: 9600,
Data bits: 8,
Parity: None,
Stop bits: 1,
Flow control: None
void MainWindow::openSerialPort()
{
SettingsDialog::Settings p = settings->settings();
serial->setPortName(p.name);
serial->setBaudRate(p.baudRate);
serial->setDataBits(p.dataBits);
serial->setParity(p.parity);
serial->setStopBits(p.stopBits);
serial->setFlowControl(p.flowControl);
if (serial->open(QIODevice::ReadWrite)) {
console->setEnabled(true);
console->setLocalEchoEnabled(p.localEchoEnabled);
ui->actionConnect->setEnabled(false);
ui->actionDisconnect->setEnabled(true);
ui->actionConfigure->setEnabled(false);
showStatusMessage(tr("Connected to %1 : %2, %3, %4, %5, %6")
.arg(p.name).arg(p.stringBaudRate).arg(p.stringDataBits)
.arg(p.stringParity).arg(p.stringStopBits).arg(p.stringFlowControl));
} else {
QMessageBox::critical(this, tr("Error"), serial->errorString());
showStatusMessage(tr("Open error"));
}
}
void MainWindow::readData()
{
QByteArray data = serial->readAll();
console->putData(data);
}
Simply you must configure serial port after that you have open it. If you open the port after these instruction:
serial->setBaudRate(p.baudRate);
serial->setDataBits(p.dataBits);
serial->setParity(p.parity);
serial->setStopBits(p.stopBits);
serial->setFlowControl(p.flowControl);
they was ignored. Your second program configure right the serial port for you and the configuration remain when you start your program.
Try this:
void MainWindow::openSerialPort()
{
SettingsDialog::Settings p = settings->settings();
serial->setPortName(p.name);
if (serial->open(QIODevice::ReadWrite)) {
serial->setBaudRate(p.baudRate);
serial->setDataBits(p.dataBits);
serial->setParity(p.parity);
serial->setStopBits(p.stopBits);
serial->setFlowControl(p.flowControl);
console->setEnabled(true);
console->setLocalEchoEnabled(p.localEchoEnabled);
ui->actionConnect->setEnabled(false);
ui->actionDisconnect->setEnabled(true);
ui->actionConfigure->setEnabled(false);
showStatusMessage(tr("Connected to %1 : %2, %3, %4, %5, %6")
.arg(p.name).arg(p.stringBaudRate).arg(p.stringDataBits)
.arg(p.stringParity).arg(p.stringStopBits).arg(p.stringFlowControl));
} else {
QMessageBox::critical(this, tr("Error"), serial->errorString());
showStatusMessage(tr("Open error"));
}
}
void MainWindow::readData()
{
QByteArray data = serial->readAll();
console->putData(data);
}
You must pay attention when configuring a serial port, any option can return true or false; best practice want to check and manage every error that can be returned.

Controlling Arduino Mega Ramps 1.4 using Johnny-five

I want to control a Arduino Mega with a Ramps 1.4 shield using Johnny-five.
I uploaded the Standard Firmata the Arduino board and tried to run this code:
var five = require('johnny-five');
var board = new five.Board();
board.on('ready',function(){
console.log('Board is ready');
});
My error:
1448365609699 Device(s) COM3,COM5
1448365609707 Connected COM3
1448365619710 Device or Firmware Error A timeout occurred while connecting to the Board.
Please check that you've properly flashed the board with the correct firmware.
See: https://github.com/rwaldron/johnny-five/wiki/Getting-Started#trouble-shooting
enter code here
events.js:146
throw err;
^
Error: Uncaught, unspecified "error" event. ([object Object])
at Board.emit (events.js:144:17)
at Board.log (C:\Users\Digital Hammer\Documents\Electric lab playground\test\node_modules\johnny-five\lib\board.js:633:8)
at Board.(anonymous function) [as error] (C:\Users\Digital Hammer\Documents\Electric lab playground\test\node_modules\johnny-five\lib\board.js:644:14)
at Board.<anonymous> (C:\Users\Digital Hammer\Documents\Electric lab playground\test\node_modules\johnny-five\lib\board.js:414:14)
at Timer.listOnTimeout (timers.js:92:15)
Does anyone have any ideas why it does not work?
var five = require('johnny-five');
var board = new five.Board({
port :"com5"
});
board.on('ready',function(){
console.log('Board is ready');
});
The js file didn't connect to the correct port. I need to set it to the one which is COM5.

Allocating memory in Flash for user data (STM32F4 HAL)

I'm trying to use the internal flash of an STM32F405 to store a bunch of user settable bytes that remain after rebooting.
I'm using:
uint8_t userConfig[64] __attribute__((at(0x0800C000)));
to allocate memory for the data I want to store.
When the program starts, I check to see if the first byte is set to 0x42, if not, i set it using:
HAL_FLASH_Unlock();
HAL_FLASH_Program(TYPEPROGRAM_BYTE, &userConfig[0], 0x42);
HAL_FLASH_Lock();
After that I check the value in userConfig[0] and I see 0x42... Great!
When I hit reset, however, and look at the location again, it's not 0x42 anymore...
Any idea where I'm going wrong? I've also tried:
#pragma location = 0x0800C00
volatile const uint8_t userConfig[64]
but I get the same result..
Okay I found an answer on the ST forums thanks to clive1. This example works for an STM32F405xG.
First we need to modify the memory layout in the linker script file (.ld file)
Modify the existing FLASH and add a new line for DATA. Here I've allocated all of section 11.
MEMORY
{
FLASH (RX) : ORIGIN = 0x08000000, LENGTH = 1M-128K
DATA (RWX) : ORIGIN = 0x080E0000, LENGTH = 128k
...
...
}
Manual for editing linker files on the sourceware website
In the same file, we need to add:
.user_data :
{
. = ALIGN(4);
*(.user_data)
. = ALIGN(4);
} > DATA
This creates a section called .user_data that we can address in the program code.
Finally, in your .c file add:
__attribute__((__section__(".user_data"))) const uint8_t userConfig[64]
This specifies that we wish to store the userConfig variable in the .user_data section and const makes sure the address of userConfig is kept static.
Now, to write to this area of flash during runtime, you can use the stm32f4 stdlib or HAL flash driver.
Before you can write to the flash, it has to be erased (all bytes set to 0xFF) The instructions for the HAL library say nothing about doing this for some reason...
HAL_FLASH_Unlock();
__HAL_FLASH_CLEAR_FLAG(FLASH_FLAG_EOP | FLASH_FLAG_OPERR | FLASH_FLAG_WRPERR | FLASH_FLAG_PGAERR | FLASH_FLAG_PGSERR );
FLASH_Erase_Sector(FLASH_SECTOR_11, VOLTAGE_RANGE_3);
HAL_FLASH_Program(TYPEPROGRAM_WORD, &userConfig[index], someData);
HAL_FLASH_Lock();

Qt5.4 QAudioOutput on Raspberry Pi With PulseAudio on the 3.5mm Audio Jack Doesn't work but Qt 5.3 Does

Qt5.3 sees the default Raspberry Pi also_output.0.analog-mono device ( 3.5 mm headphone jack ) and QAudioOutput from 5.3 successfully writes audio to that device and I can hear the audio with my headphones. This all works with default Raspbian, with PulseAudio 2.0 from apt-get, and no extra configuration. PulseAudio is run as session process and not in the System Daemon mode. Qt 5.4 does not see the device with the exact same source code and Raspbian ( except cross-compiled with Qt 5.4.0 and not Qt 5.3.2 ) and also cannot write data to it.
It gives me this error ( Please note that I've manually assigned both sys default:CARD=ALSA and 'default' but they both return the same 'snd_pcm_hw_params' error ):
Output Device name: "sysdefault:CARD=ALSA"
Output Device name: "default"
Default device is "default"
Output device is: "default"
"QAudioOutput: snd_pcm_hw_params: err = -12"
Pactl sees it:
pactl list sinks
Sink #0
State: SUSPENDED
Name: alsa_output.0.analog-mono
Description: bcm2835 ALSA Analog Mono
Driver: module-alsa-card.c
Sample Specification: u8 1ch 8000Hz
I've tried to modify /etc/pulse/default.pa with this at the bottom to force the output device:
load-module module-alsa-sink sink_name=alsa_output.0.analog-mono device=hw:0
set-default-sink alsa_output.0.analog-mono
Here is my setup code that gives the error:
// Coordinator receives Audio data
m_Format.setSampleRate(8000);
m_Format.setChannelCount(1);
m_Format.setSampleSize(8);
m_Format.setCodec("audio/pcm");
m_Format.setByteOrder(QAudioFormat::BigEndian);
m_Format.setSampleType(QAudioFormat::UnSignedInt);
QAudioDeviceInfo infoOut(QAudioDeviceInfo::defaultOutputDevice());
foreach (const QAudioDeviceInfo &deviceInfo, QAudioDeviceInfo::availableDevices(QAudio::AudioOutput)) {
qDebug() << "Output Device name: " << deviceInfo.deviceName();
}
qDebug() << "Default device is" << infoOut.deviceName();
if (!infoOut.isFormatSupported(m_Format))
{
qDebug()<< "Default format not supported - trying to use nearest";
m_Format = infoOut.nearestFormat(m_Format);
}
qDebug() << "Output device is: " << infoOut.deviceName();
m_AudioOutput = new QAudioOutput(infoOut, m_Format, this);
// This data accumulates and dumps data to output
m_DataForOutput.clear();
// Now Start playing
// m_Output gets written to to send data to speakers
m_Output = m_AudioOutput->start();
What in the world is going on? How come the same configuration works with 5.3.2 and not 5.4.1. Assigning the default audio device doesn't work... What can I do here and how can I make it work? Thanks!
The answer was to run in session mode ( not a system-wide PulseAudio daemon ) and edit default.pa to look like this:
## Create the default output device
#load-module module-udev-detect tsched=0
load-module module-alsa-card device_id=0
#load-module module-alsa-card device_id=0 tsched=0 fragments=10 fragment_size=640 tsched_buffer_size=4194384 tsched_buffer_watermark=262144
#load-module module-alsa-card device_id=0 tsched=0 fragments=6 fragment_size=16 tsched_buffer_size=4194384 tsched_buffer_watermark=262144
load-module module-suspend-on-idle timeout=86400
### Load several protocols
load-module module-native-protocol-unix
### Make sure we always have a sink around, even if it is a null sink.
#load-module module-always-sink

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