C8051F045 View Datasheet(PDF) - Silicon Laboratories

Part Name

Description

Manufacturer

C8051F045

Mixed Signal ISP Flash MCU Family

Silicon Laboratories 

C8051F040/1/2/3/4/5/6/7

18.1. Bosch CAN Controller Operation

The CAN Controller featured in the C8051F04x family of devices is a full implementation of Bosch’s full

CAN module and fully complies with CAN specification 2.0B. A block diagram of the CAN controller is

shown in Figure 18.2. The CAN Core provides shifting (CANTX and CANRX), serial/parallel conversion of

messages, and other protocol related tasks such as transmission of data and acceptance filtering. The

message RAM stores 32 message objects which can be received or transmitted on a CAN network. The

CAN registers and message handler provide an interface for data transfer and notification between the

CAN controller and the CIP-51.

The function and use of the CAN Controller is detailed in the Bosch CAN User’s Guide. The User’s Guide

should be used as a reference to configure and use the CAN controller. This Silicon Labs data sheet

describes how to access the CAN controller.

The CAN Controller is typically initialized using the following steps:

Step 1. Set the SFRPAGE register to CAN0_PAGE.

Step 2. Set the INIT the CCE bits to ‘1’ in the CAN0CN Register. See the CAN User’s Guide for bit

definitions.

Step 3. Set timing parameters in the Bit Timing Register and the BRP Extension Register.

Step 4. Initialize each message object or set it’s MsgVal bit to NOT VALID.

Step 5. Reset the INIT bit to ‘0’.

The CAN Control Register (CAN0CN), CAN Test Register (CAN0TST), and CAN Status Register

(CAN0STA) in the CAN controller can be accessed directly or indirectly via CIP-51 SFR’s. All other CAN

registers must be accessed via an indirect indexing method described in Section “18.2.5. Using

CAN0ADR, CAN0DATH, and CANDATL to Access CAN Registers” on page 232.

CANTX

CANRX

C8051F04x

CAN Controller

S

TX

RX

CAN

CAN_CLK

Y

BRP

S

Prescaler

(fsys)

C

L

Core

K

Message RAM

(32 Message Objects)

REGISTERS

CIP-51

MCU

S

F

R

's

Message Handler

Interrupt

Figure 18.2. CAN Controller Diagram

228

Rev. 1.5

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