User Manual
438
Rev. 1.1
2019-03-18
TLE984xQX
Microcontroller with LIN and Power Switches for Automotive Applications
General Purpose Timer Units (GPT12)
Timer T3 Output Toggle Latch
The overflow/underflow signal of timer T3 is connected to a block named ‘Toggle Latch’, shown in the Timer
Mode diagrams.
illustrates the details of this block. An overflow or underflow of T3 will clock two
latches: The first latch represents bit T3OTL in control register T3CON. The second latch is an internal latch
toggled by T3OTL’s output. Both latch outputs are connected to the input control blocks of the auxiliary timers
T2 and T4. The output level of the shadow latch will match the output level of T3OTL, but is delayed by one
clock cycle. When the T3OTL value changes, this will result in a temporarily different output level from T3OTL
and the shadow latch, which can trigger the selected count event in T2 and/or T4.
When software writes to T3OTL, both latches are set or cleared simultaneously. In this case, both signals to the
auxiliary timers carry the same level and no edge will be detected. Bit T3OE (overflow/underflow output
enable) in register T3CON enables the state of T3OTL to be monitored via an external pin T3OUT. When T3OTL
is linked to an external port pin (must be configured as output), T3OUT can be used to control external HW. If
T3OE = 1, pin T3OUT outputs the state of T3OTL. If T3OE = 0, pin T3OUT outputs a high level (as long as the
T3OUT alternate function is selected for the port pin).
The trigger signals can serve as an input for the counter function or as a trigger source for the reload function
of the auxiliary timers T2 and T4.
As can be seen from
, when latch T3OTL is modified by software to determine the state of the output
line, also the internal shadow latch is set or cleared accordingly. Therefore, no trigger condition is detected by
T2/T4 in this case.
Figure 86 Block Diagram of the Toggle Latch Logic of Core Timer T3 (x = 3)
m c_ g p t0 1 0 6 _ o tl.vsd
T o g g le L a tch L o g ic
T xO U T
S e t/C le a r (S W )
C o re T im e r
O ve rflo w /
U n d e rflo w
Shadow
Latch
1
0
MUX
1
T x O E
TxO TL
T o P o rt L o g ic
T o A u x . T im e r
In p u t L o g ic