Hi,
I am using a Sparkfun redboard, which is almost identical to Arduino Uno R3, and I collect data over TWI (I2C) from MPU6050 sensor. I receive 36 bytes of data from the FIFO (1024 bytes) in the sensor in one shot when the FIFO has more than 36 bytes, and I have some issues due to the 32 bytes of TWI buffer on Arduino side.
I just changed the TWI_BUFFER_LENGTH in twi.h (Arduino/hardware/arduino/avr/libraries/Wire/utility/) from the default value of 32 to 64 bytes. I also changed BUFFER_LENGTH in Wire.h (Arduino/hardware/arduino/avr/libraries/Wire/) to 64 bytes.
But when reading 36 bytes of data, Arduino can read the first 32 bytes correctly, but the last four bytes still have all zeros. So, it seems the change is not effective at all.
Also, the dynamic memory does not change at all from the current one, which is roughly 500 bytes out of 2kB. As far as I know, Arduino uses five buffers regarding TWI, so increasing from 32 to 64 bytes will need additional 160 bytes of memory, but I do not see any change.
Is there something else that I need to do in order to increase the buffer size up to 64 bytes for TWI or I2C? Your help will be greatly appreciated.