RM0319 datasheet(200/368 Pages) STMICROELECTRONICS

200 / 368 page

Controller area network ports (CAN)

RM0319

200/368

Doc ID 022640 Rev 3

feedback from its Tx output to its Rx input. The actual value of the CAN_RX input pin is

disregarded by the CAN core. The transmitted messages can be monitored at the CAN_TX

pin.

15.4.7

Using the loop back mode combined with silent mode

It is also possible to combine loop back mode and silent mode by programming LBack and

Silent bits to one at the same time. This mode can be used for a “Hot Selftest”, which means

that the CAN can be tested without affecting a running CAN system connected to the pins

CAN_TX and CAN_RX. In this mode, the CAN _RX pin is disconnected from the CAN core

and the CAN_TX pin is held rescessive. The following figure shows the connection of

signals CAN_TX and CAN_RX to the CAN core in case of the combination of loop back

mode with silent mode.

Figure 70.

CAN core in loop back combined with silent mode

15.4.8

Managing message objects

Figure 71.

Message identifier formats

CAN Core

C_CAN

CAN_TX

CAN_RX

Bus

idle

DLC

Arbitration field

Control field

Bus

idle

11-bit Identifier

Arbitration field

Control field

18-bit Identifier

11-bit Identifier

DLC

Standard format: 11-bit message identifier

Extended format: 29-bit message identifier

RM0319 데이터시트(PDF) 200 Page - STMicroelectronics