CP3BT26

19.10CAN CONTROLLER REGISTERS

Table 51 lists the CAN module registers.

Table 51 CAN Controller Registers

Name

Address

Description

 

 

 

 

 

 

CNSTAT

See

CAN Buffer Status/

Table 50.

Control Register

 

 

 

 

CGCR

0E F100h

CAN Global

Configuration Register

 

 

 

 

 

CTIM

0E F102h

CAN Timing Register

 

 

 

GMSKX

0E F104h

Global Mask Register

 

 

 

GMSKB

0E F106h

Global Mask Register

 

 

 

BMSKX

0E F108h

Basic Mask Register

 

 

 

BMSKB

0E F10Ah

Basic Mask Register

 

 

 

CIEN

0E F10Ch

CAN Interrupt

Enable Register

 

 

 

 

 

CIPND

0E F10Eh

CAN Interrupt

Pending Register

 

 

 

 

 

CICLR

0E F110h

CAN Interrupt

Clear Register

 

 

 

 

 

CICEN

0E F112h

CAN Interrupt Code

Enable Register

 

 

 

 

 

CSTPND

0E F114h

CAN Status

Pending Register

 

 

 

 

 

CANEC

0E F116h

CAN Error

Counter Register

 

 

 

 

 

CEDIAG

0E F118h

CAN Error

Diagnostic Register

 

 

 

 

 

CTMR

0E F11Ah

CAN Timer Register

 

 

 

19.10.1 Buffer Status/Control Register (CNSTAT)

The buffer status (ST), the buffer priority (PRI), and the data length code (DLC) are controlled by manipulating the con- tents of the Buffer Status/Control Register (CNSTAT). The CPU and CAN module have access to this register.

15

12

11

8

 

7

4

3

0

DLC

 

Reserved

 

 

PRI

 

ST

 

 

 

 

 

 

 

 

 

 

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R/W

 

 

 

 

 

 

 

 

 

ST

The Buffer Status field contains the status in-

 

formation of the buffer as shown in Table 52.

This field can be modified by the CAN module. The ST0 bits acts as a buffer busy indication. When the BUSY bit is set, any write access to the buffer is disabled with the exception of the lower byte of the CNSTAT register. The CAN module sets this bit if the buffer data is cur- rently copied from the hidden buffer or if a message is scheduled for transmission or is currently transmitting. The CAN module al- ways clears this bit on a status update.

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National CP3BT26 manual Can Controller Registers Name Address Description, Buffer Status/Control Register Cnstat