TTCAN Getting Started on TC1796-Board & Toolkits

AP29006

TTCAN Getting Started

MultiCAN Module in TC1796

– an FSE regards itself synchronized to the network after the occurrence of the second consecutive reference message

– During synchronization, nodes will not transmit any messages and global time is regarded as invalid.

– The init watch trigger is taken into account until the first message is correctly received or transmitted. An init watch trigger event is detected when the cycle

time reaches the value of 2 16 -1.

4.7

Operation Monitor and Failure Handling

ISO terms and definition:

Tx count: it resets at start of each matrix cycle. It increments on each active trigger: Tx count max

= expected Tx trigger.

In case the maximum number of Tx triggers has been reached, no further transmission in exclusive time windows takes place for this device.

Tx overflow: in case Tx trigger reaches the expected Tx trigger value, the Tx

overflow flag will be set

Tx underflow: in case not all Tx triggers became active within a matrix cycle

Expected Tx trigger: threshold value of maximum amount of Tx triggers in one matrix cycle

MultiCAN Implementation:

• 8-bit field EXPTT (expected Tx triggers) in the register TTCFGR (time trigger configuration register)

• 4-bit field MSC(0…7) in the register MOFCRn (message object function register) indicates message status count. It is to detect scheduling errors for exclusive time

windows. A scheduling error is detected, when MSC is greater than 7 or the difference between the highest MSC and lowest MSC of all messages on this CAN node is larger than 2 within one system matrix.

4.7.1

MultiCAN Implementation

Four levels of error severity:

• S0: no error, normal operation

• S1: warning/only notification, interrupt flag is set

– MSC

MAX

– MSC

MIN

> 2 at the end of a matrix cycle

– A receive message object has reached its MSC of 7

– Tx underflow: Not all transmit triggers were active.

• S2: error, interrupt flag is set. if TTCFGR.RTO=127 all transmission are disabled

(except reference messages).

– A transmit-message object reached an MSC of 7

– Tx overflow, more than the number of specified Tx triggers has been taken

Application Note 25 V1.2, 2008-08

AP29006

TTCAN Getting Started

MultiCAN Module in TC1796

• S3: severe error. Init bit is set, all CAN bus operation is stopped.

– Application Watchdog, the application failed to service the watchdog.

– bus off

– Configuration error: a merged arbitration window is not properly closed or a Tx

trigger occurs in reference message time window

– Watch trigger event: this trigger occurs if the reference message is missing (the time master stopped sending reference messages)

Three interrupt groups:

Error

TENWER

TTER

WTE

AWD

SE

Notification

NBC

Tx Enable Window Error transmit trigger error watch trigger event application watchdog scheduler error new basic cycle interrupt line Flag

ERRINP

ERRINP

TENWER

TTOF/TTUF

ERRINP

ERRINP

ERRINP

IWTE/WTE

AWDERR

SERR1/SERR2 interrupt line Flag

NBCINP NBC

ERRSC

MSRC

SYNCSC

NOTIF error state change NOTIFINP master-slave relation change NOTIFINP synchronization state change NOTIFINP notification NOTIFINP

ERRS

MSR

SYNCS

WFE/DISC

Application Note 26 V1.2, 2008-08

TTCAN interrupt structure:

AP29006

TTCAN Getting Started

MultiCAN Module in TC1796

Figure 12 TTCAN Interrupt Structure

Register TIER (Time Trigger Interrupt Enable Register):

Application Note 27 V1.2, 2008-08

AP29006

TTCAN Getting Started

MultiCAN Module in TC1796

Register TTINPR (Time Trigger Interrupt Node Pointer Register):

Register TTIRR (Time Trigger Interrupt Request Register):

Application Note 28 V1.2, 2008-08