=============== TWI test plan =============== Test slave will update its slave send buffer with received data from master. Read slave buffer after each transmission. - master send 1 byte. - master send n bytes, less than slave limit. - master send n bytes, same as slave limit. - master send n bytes, more than slave limit. > should be interrupted at slave limit. - master send 0 byte. > master can send 0 byte, but test slave should not update slave send > buffer as 0 is forbidden. - master recv 0 byte. > will receive a byte anyway. - master recv 1 byte. - with slave buffer size 1 and m: - master recv n byte, less than slave limit. - master recv n byte, same as slave limit. - master recv n byte, more than slave limit. > can not be interrupted, will read 0xff. - master send to unknown slave. - master recv to unknown slave.