Gets the number of bytes (characters) available for writing in the serial buffer without blocking the write operation.
port.availableForWrite()
none
the number of bytes available to write
#include <PhpocExpansion.h>
#include <Phpoc.h>
#define BUFFER_SIZE 100 // read and write buffer size, reduce it if memory of Arduino is not enough
byte spcId = 1;
ExpansionSerial port(spcId);
byte rwbuf[BUFFER_SIZE]; // read and write buffer
void setup() {
Serial.begin(9600);
while(!Serial)
;
Phpoc.begin(PF_LOG_SPI | PF_LOG_NET);
Expansion.begin();
port.begin("115200N81N");
}
void loop() {
// Get the number of bytes available for writing
int txfree = port.availableForWrite();
int rxlen = port.available();
if(rxlen > 0) {
if(rxlen <= txfree) {
int rwlen; // read and write length
if(rxlen <= BUFFER_SIZE)
rwlen = rxlen;
else
rwlen = BUFFER_SIZE;
// receive data
rwlen = port.readBytes(rwbuf, rwlen);
// send data
port.write(rwbuf, rwlen);
// print data to serial monitor of Arduino IDE
Serial.write(rwbuf, rwlen);
}
}
delay(1);
}