MikroElektronika PIC Microcontrollers PIC18 Manual do Utilizador descarregar pdf (Página 19)

The CAN module in the PIC18F258 microcontroller has six modes of operation:



Configuration mode



Disable mode



Normal operation mode



Listen-only mode



Loop-back mode



Error recognition mode

9.9.1 Configuration Mode

The CAN module is initialized in configuration mode. The module is not allowed to

enter configuration mode while a transmission is taking place. In configuration mode

the module will neither transmit nor receive, the error counters are cleared, and the

interrupt flags remain unchanged.

9.9.2 Disable Mode

In disable mode, the module will neither transmit nor receive. In this mode the internal

clock is stopped unless the module is active. If the module is active, it will wait for

11 recessive bits on the CAN bus, detect that condition as an IDLE bus, and then accept

the module disable command. The WAKIF interrupt (wake-up interrupt) is the only

CAN module interrupt that is active in disable mode.

9.9.3 Normal Operation Mode

The normal operation mode is the CAN module’s standard operating mode. In this

mode, the module monitors all bus messages and generates acknowledge bits, error

frames, etc. This is the only mode that can transmit messages.

9.9.4 Listen-only Mode

The listen-only mode allows the CAN module to receive messages, including

messages with errors. It can be used to monitor bus activities or to detect the baud

rate on the bus. For automatic baud rate detection, at least two other nodes must be

www.newnespress.com

493Advanced PIC18 Projects—CAN Bus Projects

1 2 ... 14 15 16 17 18 19 20 21 22 23 24 ... 39 40

Sem comentários

MikroElektronika PIC Microcontrollers PIC18 Manual do Utilizador Página 19