Mikal

I have the PC connected to the Duemilanove via USB, then pin 3 of the arduino (Tx) connected to the serial connection on a Milford Instruments LCD display screen. Data sheet – http://www.milinst.co.uk/shop/LCDs/pdf/6_201.pdf which accepts baud rates of 9600 or 2400 depending on the baud jumper, is 8bit, no parity and one stop bit.

Basically the Duemilanove should be acting as a USB to serial converter. The sketch is as follows:

#include

NewSoftSerial lcd(2, 3);

void setup()
{
pinMode(13, OUTPUT);
digitalWrite(13, HIGH);
Serial.begin(9600);
lcd.begin(9600);
}

void loop()
{
if(Serial.available())
{
char c = Serial.read();
lcd.print(c);
Serial.print(c);
Serial.print((bool) lcd.overflow());
}
}

Should be reading from Serial (1 char at a time) then printing to the LCD display via pin 3 (additional Serial prints for debugging)..

At the PC side I have a python script to send the commands (clear the LCD display, reset the cursor position and send some ‘test’ text).

At 9600 baud either side of the Arduino, data is getting through to the display screen but about 50% of the time at least 1 of the 4 characters that make up the initial string is garbled. However the messages that come back through the USB serial port to the PC are always correct and there’s no overflow.

Connecting the LCD display directly to the PC with a serial cable and with a USB to serial converter (PL2303) it works 100% of the time fine. I’m assuming it’s got to be related to the NSS write function..?

Mikal

Mikal

Thanks for the library. I’m having a little trouble getting it to read data from a GPS. I’m using a very basic sketch (attached), but I just get strings of garbage on the screen

I can read the GPS data using hyperterminal without problems, it auto-detects the connections settings as 4800 baud, 8 bit, no parity. The data displayed by hyperterminal is fine, so I know the GPS is working.

Any suggestions appreciated.

Regards

Mike

#include

NewSoftSerial mySerial = NewSoftSerial(2, 3);

#define BUFFSIZ 90 // plenty big
char buffer[BUFFSIZ];
char buffidx;

void setup()
{
Serial.begin(4800);
mySerial.begin(4800);
Serial.println(“\n\rNewSoftSerial + GPS test”);
}

void loop()
{
Serial.print(“\n\rread: “);
readline();
}

void readline(void) {
char c;
buffidx = 0; // start at begninning
while (1) {
c=mySerial.read();
if (c == -1)
continue;
Serial.print(c);
if (c == ‘\n’)
continue;
if ((buffidx == BUFFSIZ-1) || (c == ‘\r’)) {
return;
}
buffidx++;
}
}

Yes, that is possible. Someday when I get time I may modify the library to allow that. Meanwhile, if you’d like to take a shot at it, you can look at the section in recv() labeled “// skip the stop bit”. Similarly, in the “write” routine, look at the stop bit delay at the very end of the routine.

Thanks for the note.

Mikal

It is important to wait for the byte to arrive, but rather than waiting an arbitrary number of milliseconds, why not just wait until NewSoftSerial tells you that the data arrived?

while (nsSerial.available == 0)
;

Mikal

I want to use this library to communicate with a distance sensor (SRF485). The problem is this sensor uses 2 stop bits for both RX and TX. Is it possible to modify the library for 2 stop bits instead of 1 for both printing and reading? If so, can you please advise?

Thanks
Frits