Serial.readBytes()

※ Anmerkungen und Warnungen:

• Serial.readBytes() may read a stream of bytes in multiple times (resulting in multiple fragments). To read a stream of bytes at one time, there are two ways:
• Based on the delimiter: Use Serial.readBytesUntil() with delimiter.
• Based on the fixed length: Wait until the fixed number of bytes is available. for example:
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const int BUFFER_SIZE = 5; char buf[BUFFER_SIZE]; void setup() { Serial.begin(9600); // opens serial port, sets data rate to 9600 bps } void loop() { // check if data is available if (Serial.available() >= BUFFER_SIZE) { // read the incoming bytes: Serial.readBytes(buf, BUFFER_SIZE); // TODO: PROCESS THE INCOMING DATA HERE } }
• Make sure that the read length does NOT exceed the buffer size. The below is the best practice:
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const int BUFFER_SIZE = 5; char buf[BUFFER_SIZE]; // application buffer void setup() { Serial.begin(9600); // opens serial port, sets data rate to 9600 bps } void loop() { // check if data is available int rxlen = Serial.available(); // number of bytes available in Serial buffer if (rxlen > 0) { int rlen; // number of bytes to read if (rxlen > BUFFER_SIZE) // check if the data exceeds the buffer size rlen = BUFFER_SIZE; // if yes, read BUFFER_SIZE bytes. The remaining will be read in the next time else rlen = rxlen; // read the incoming bytes: rlen = Serial.readBytes(buf, rlen); // TODO: PROCESS THE INCOMING DATA HERE } }
• Serial functions are not only used for the communication between an Arduino board and Serial Monitor of Arduino IDE but also used for the communication between:
• An Arduino board and other Arduino board
• An Arduino board and other sensors/devices
• An Arduino board and computer (any Serial software on computer)