Hi all,
i had this question a few weeks back , after the change in flush() method it had become quite difficult to empty the serial buffer , so to all those who require to send large amounts of data from processing or serial monitor to arduino, just use this code. Only prerequisite is that the data must be sent as a bulk, no delays are required.
void loop()
{
if (Serial.available())
{
val="";
while(Serial.available())
{
char t= Serial.read();
val=val+t;
}
Serial.println(val);
Serial.end(); // Ends the serial communication once all data is received
Serial.begin(9600); // Re-establishes serial communication , this causes deletion of anything previously stored in the buffer //or cache
}
}
later u can just use the substring method to extract from val
I'm still of the opinion that any attempt to 'flush' the serial input buffer is flawed thinking as one has no control over what and when new serial data my arrive, possibly even between the ending of the flushing function but before returning to further processing that assumes the input buffer is empty when it's possible it is not, esp at the higher baud rates.
I think this kind of requirement is better met by 'building' it into the serial protocol so that one can simply throw away all characters until a valid start of packet character is read and then save characters until you get a valid end of packet character. So build the structure into the protocol rather then assuming what may or may not arrive or assuming what data you don't need even though you haven't determine what those flushed characters might represent.
Recall that the older arduino flushing function did clear the serial input buffer, but they changed it around IDE => 1.0 to flush only the output transmit buffer and left no function to clear the input buffer. If it was a useful or logical function why would they remove that functionality? I certainly am open to what others may have to say on this subject.
Strange. My serial code generally has output waiting, it no-blocks serial input and never reads more than 1 char per loop() it's generally a lot of loops() between serial available even at 115200 baud.
Isn't flush() supposed to flush the transmit buffer? That's the one you can load 1000's of times faster than it can send.
The only serial input you should have trouble keeping up with is SPI.
But if you do have problems keeping up with serial, you might want to find out what's blocking in your code.
I recently had a similar problem to send data to Arduino Unity and I developed this little demonstration.
It has the advantage of adjusting the write speed of Arduino speed at which empties buffe ...
Please note that is just a small demonstration.
int MaxBytesAvailable;
int CurrentAvailable;
int delayNumber=1000;
int n;
String messageOut;
void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
MaxBytesAvailable=Serial.availableForWrite();
}
void loop() {
// put your main code here, to run repeatedly:
messageOut="";
messageOut+=Serial.availableForWrite();
messageOut+=" Current Delay =";
messageOut+=delayNumber;
Serial.println(messageOut);
for(n=0;n<delayNumber;n++)
{
if((CurrentAvailable=Serial.availableForWrite())>=MaxBytesAvailable) break;
}
if (CurrentAvailable>(MaxBytesAvailable/2))
{
delayNumber-=100;
if(delayNumber<0)delayNumber=0;
}
else
{
delayNumber+=100;
if(delayNumber>65000) delayNumber=65000;
}
}
What about just adding a simple while loop whenever you want to clear the buffer?
while(Serial.available()){Serial.read();}
In my design, there shouldn't be any data in the buffer, but I include this just in case there was some old data that didn't get read for some reason.
all that is so complicated and abit long winded, why cant it just be serial.clear, or if (serial.read = "clear" ) {
} serial.clear}
or something along them lines! omfg!
Its a project im working on dw about it. how can i clear it with a small command not a 10 mile long bit of bloated code, who can help without asking 20 questions as im in a poker tour right now!
Im a noob at c so all I see is long code and that's all i have to work with, please give me a really basic example, the serial buffer normally gets outputted to the lcd screen, but the lcd is 16, 1 and fills up and stops any more input and even puts in strange chars if i try to add more in so maybe i need to use the lcd.clear but then it might just fill with the serial buffer again and it wont achieve any clearing, so i think clearing the serial buffer aswell as lcd.clear will work a lot better but have no idea what the code to do that is.
omfg, soooooooo many questions and they are dumb ones! its a standard means theres no model number no make nothing just google standard 16,2 arduino lcd kit and it dont matter they are all same except mine has i2c board again a standard thing look for the most common i have that, simples! h/w dont even matter its a software thing!
I basically made an lcd display that uses a file / path requests from a form all to save having to use sd card for displaying things but want to be able to rewrite it and the program know if new input detected if yes then change sort of thing but im novice and not got a clue the best way to do this, it sort of works but not stangle due to after a long while it clears itself anyone help?
aditya123:
Hi all,
i had this question a few weeks back , after the change in flush() method it had become quite difficult to empty the serial buffer , [...].
Unfortunately, I could never figure out the meaning/significance ofemptying the serial buffer.
A: Emptying the Serial Buffer of the Receiver Section
Data comes to the receiver one character at a time. When the character arrives, it is immediately read upon and is saved in an user defined array. If so, how a serial buffer can get full and such we need to empty/flush it after reading the data. It is only one byte long buffer as I understand. If we don't read the character that has just arrived, there is a possibility that the character byte might be overwritten by the arrival of the next character. Therefore, the speed of data read must be higher than the speed (the Bd) at which data arrives.
B: Serial Buffer of the Transmit Section.
In UART Protocol, one character is transmitted at a time. If so, the execution of the command Serial.print("Arduino"); requires that there should be an intermediate buffer to hold the characters of the message Arduino. As I understand, the transmission of Serial.print("Arduino"); is composed of the following 7 sub transmissions:
If the buffer size of the Transmit Section is 64 byte, only 64 characters of the following message should be transferred and the remaining characters are either lost or queued somewhere. Practically, it is observed that the whole text has appeared on the Se rail Monitor.
Serial.println("//put your setup code here, // put your setup code here, to run once: // put your setup code here, to run once: // put your setup code here, to run once:");
plz