BasicCAN is the strategy usually used in cheaper standalone CAN controllers or in smaller microcontrollers with an on-chip CAN controller peripheral. A BasicCAN controller normally has one transmit buffer and two receive buffers. A message is sent by writing it to the transmit buffer. The receive buffers are arranged in a FIFO structure and can receive every CAN message. A message can be received into one buffer while the microcontroller is reading the information form the other buffer. Interesting messages are filtered out using two registers that operate on the message identifier. Each bit in the identifier is checked against the filter. If the message matches the filter, it is stored in one of the receiver buffers. Each bit of the identifier filter can be set to ‘1’ or ‘0’. Often the filter only operates on 8 of the 11 bits in the Standard CAN identifier, so the 3  lowest ID bits are always ‘don’t care.’