Intel 87C196CB Manual De Usuario

7-29

The CAN controller has a single interrupt input (INT13) to the interrupt controller. (Generally,
PTS interrupt service is not useful for the CAN controller because the PTS cannot readily deter-
mine the source of the CAN controller’s multiplexed interrupts.) To enable the CAN controller’s
interrupts, you must enable the interrupt source by setting the CAN bit in INT_MASK1 (see Ta-
ble 7-2 on page 7-3) and globally enable interrupt servicing (by executing the EI instruction). In
addition, you must set bits in the CAN control register (Figure 7-17) and the individual message
objects’ control register 0 (Figure 7-18) to enable the individual interrupt sources within the CAN
controller. 

Address:

Reset State:

1E00H

01H

Program the CAN control (CAN_CON) register to control write access to the bit timing registers, to 
enable and disable CAN interrupts, and to control access to the CAN bus.

—

CCE

—

—

EIE

SIE

IE

INIT

7

—

Reserved; for compatibility with future devices, write zero to this bit.

6

CCE

Change Configuration Enable

5:4

—

Reserved; for compatibility with future devices, write zeros to these bits.

3

EIE

Error Interrupt Enable

This bit enables and disables the bus-off and warn interrupts.

0 = disable bus-off and warn interrupts 
1 = enable bus-off and warn interrupts 

2

SIE

Status-change Interrupt Enable

This bit enables and disables the successful reception (RXOK), successful 
transmission (TXOK), and error code change (LEC2:0) interrupts.

0 = disable status-change interrupt 
1 = enable status-change interrupt 

When the SIE bit is set, the CAN controller generates a successful 
reception (RXOK) interrupt request each time it receives a valid message, 
even if no message object accepts it.