Closed
Description
BOARD: NUCLEO-F091RC
Connected a NanoPi Neo Air (master) with the nucleo when running i2cset-y 0 0x09 on the NPI the nucleo hangs. Serial stops, blinking stop. It just freezes.
Code running on the nucleo:
#include <Wire.h>
void setup()
{
Wire.begin(0x15); // join i2c bus with address #4
Wire.onReceive(receiveEvent); // register event
Wire.onRequest(requestEvent);
Serial.begin(115200); // start serial for output
}
void loop()
{
delay(100);
}
void receiveEvent(int howMany)
{
Serial.println(howMany);
while(1 < Wire.available()) // loop through all but the last
{
int c = Wire.read(); // receive byte as a character
Serial.print(c); // print the character
}
int x = Wire.read(); // receive byte as an integer
Serial.print(c); // print the character
}
void requestEvent()
{
Wire.write("hello");
}
- It seems to be a problem in the Wire.c when running as a slave the allocateRxBuffer never gets called. So first fix seems to be to add:
// copy twi rx buffer into local read buffer
// this enables new reads to happen in parallel
+ if(rxBuffer == nullptr){
+ allocateRxBuffer(BUFFER_LENGTH);
+ }
memcpy(rxBuffer, inBytes, numBytes);
and changing allocateRxBuffer to static.
Now the freeze stopped.
- It also seems to be an error with the numBytes received from master.
Changing line 541 in twi.c
from:nbData = I2C_TXRX_BUFFER_SIZE - obj->handle.XferCount;
to:nbData = I2C_TXRX_BUFFER_SIZE - obj->handle.XferSize;
Seems to correct the problem.
Am I doing something wrong or this a actual bug?