AN2283 Freescale Semiconductor / Motorola, AN2283 Datasheet - Page 36

• Manufacturer Part Number: AN2283
• Description: Scalable Controller Area Network (MSCAN)
• Manufacturer: Freescale Semiconductor / Motorola

AN2283/D
Transmitter Warning
Interrupt
36
NOTE:
Motorola Scalable Controller Area Network (MSCAN) Interrupts
In summary, the TEC increases by eight for all TX errors and decrements by
one on a successful TX.
More than one rule may apply during a given message transfer.
The Transmitter Warning Interrupt tells the software driver that the node is in
the error active state, and the TEC value is in the range 96 <= REC < 128, at
which point the TWRNIF (Transmitter Warning Interrupt Flag) in CRFLG is set.
To enable the Transmitter Warning Error Interrupt, set the TWRNIE
(Transmitter Warning Interrupt Enable) bit in CRIER.
To handle the Transmitter Warning Interrupt source:
4. After a message transmits successfully, by getting an ACK and no error
5. The TEC is unchanged when:
1. Clear the Transmitter Error Interrupt Flag (TERRIF) bit in CRFLG by
2. Next, set the Transmitter Error Passive Interrupt Enable (TERRIE) bit in
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consecutive dominant [0] bit and after each sequence of eight additional
consecutive dominant [0] bits, every transmitter increases its Transmit
Error Count by eight.
until EOF is finished, the Transmit Error Count is decreased by one.
Unless it is zero, where it will remain the same.
–
–
writing a 1 to it. (As mentioned in
exclusive OR operation. The reason is that this state can be entered
from the Transmitter Error Passive State, where the TERRIF was set.)
These interrupt flags remain set in a level sensitive manner as long as
the setting condition remains.
CRIER. The TERRIE bit is cleared in the transmitter error passive
interrupt routine when the MSCAN transitions to the Transmitter Error
Passive State.
Transmitter is Error Passive
AND
Transmitter detects an Acknowledgement error because of not
detecting a dominant [0] ACK
AND
Transmitter doesn’t detect a dominant [0] bit while sending its
Passive Error Flag
Transmitter sends an Error Flag because a Stuff Error occurred
during arbitration whereby, the stuff bit is located before the RTR bit
AND
Stuff bit should have been recessive [1]
AND
Stuff bit has been sent as recessive [1] but is monitored as
dominant [0].
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Figure
24, CRFLG utilizes the
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