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FlexRay Module (FLEXRAYV2)
MFR4300 Data Sheet, Rev. 1
Freescale Semiconductor
193
3.4.17.1
Absolute Timer T1
The absolute timer T1 has the protocol cycle count and the macrotick count as the time base. The timer 1
interrupt flag TI1_IF in the
Protocol Interrupt Flag Register 0 (PIFR0)
is set at the macrotick start event,
if
Equation 3-24
and
Equation 3-25
are fulfilled
Eqn. 3-24
Eqn. 3-25
If the timer 1 interrupt enable bit TI1_IE in the
Protocol Interrupt Enable Register 0 (PIER0)
is asserted,
an interrupt request is generated.
The status bit T1ST is set when the timer is triggered, and is cleared when the timer expires and is
non-repetitive. If the timer expires but is repetitive, the T1ST bit is not cleared and the timer is restarted
immediately. The T1ST is cleared when the timer is stopped.
3.4.17.2
Absolute / Relative Timer T2
The timer T2 can be configured to be an absolute or relative timer by setting the T2_CFG control bit in the
Timer Configuration and Control Register (TICCR)
. The status bit T2ST is set when the timer is triggered,
and is cleared when the timer expires and is non-repetitive. If the timer expires but is repetitive, the T2ST
bit is not cleared and the timer is restarted immediately. The T2ST is cleared when the timer is stopped.
3.4.17.2.1
Absolute Timer T2
If timer T2 is configured as an absolute timer, it has the same functionality timer T1 but the configuration
from
Timer 2 Configuration Register 0 (TI2CR0)
and
Timer 2 Configuration Register 1 (TI2CR1)
is used.
On expiration of timer T2, the interrupt flag TI2_IF in the
Protocol Interrupt Flag Register 0 (PIFR0)
is
set. If the timer 1 interrupt enable bit TI1_IE in the
Protocol Interrupt Enable Register 0 (PIER0)
is
asserted, an interrupt request is generated.
3.4.17.2.2
Relative Timer T2
If the timer T2 is configured as a relative timer, the interrupt flag TI2_IF in the
Protocol Interrupt Flag
Register 0 (PIFR0)
is set, when the programmed amount of macroticks MT[31:0], defined by
Timer 2
Configuration Register 0 (TI2CR0)
and
Timer 2 Configuration Register 1 (TI2CR1)
, has expired since the
trigger or restart of timer 2. The relative timer is implemented as a down counter and expires when it has
reached 0. At the macrotick start event, the value of MT[31:0] is checked and then decremented. Thus, if
the timer is started with MT[31:0] == 0, it expires at the next macrotick start.
3.4.18
Slot Status Monitoring
The FlexRay module provides several means for slot status monitoring. All slot status monitors use the
same slot status vector provided by the PE. The PE provides a slot status vector for each static slot, for
each dynamic slot, for the symbol window, and for the NIT, on a per channel base. The content of the slot
status vector is described in
Table 3-109
. The PE provides the slot status vector within the first macrotick
after the end of the related slot/window/NIT, as shown in
Figure 3-139
.
CYCCTR.CYCCNT & T1CYSR.T1_CYC_MSK == T1CYSR.T1_CYC_VAL & T1CYSR.T1_CYC_MSK
MTCTR.MTCT == TI1MTOR.T1_MTOFFSET