User Manual
479
Rev. 1.1
2019-03-18
TLE984xQX
Microcontroller with LIN and Power Switches for Automotive Applications
General Purpose Timer Units (GPT12)
Capture/Reload Register CAPREL in Capture-And-Reload Mode
Since the reload function and the capture function of register CAPREL can be enabled individually by bits T5SC
and T6SR, the two functions can be enabled simultaneously by setting both bits. This feature can be used to
generate an output frequency that is a multiple of the input frequency.
Figure 113 Capture/Reload Register CAPREL in Capture-And-Reload Mode
This combined mode can be used to detect consecutive external events which may occur aperiodically, but
where a finer resolution, that means, more ‘ticks’ within the time between two external events is required.
For this purpose, the time between the external events is measured using timer T5 and the CAPREL register.
Timer T5 runs in Timer Mode counting up with a frequency of e.g.
f
GPT
/32. The external events are applied to
pin CAPIN. When an external event occurs, the contents of timer T5 are latched into register CAPREL and timer
T5 is cleared (T5CLR = 1). Thus, register always contains the correct time between two events, measured in
timer T5 increments. Timer T6, which runs in Timer Mode counting down with a frequency of e.g.
f
GPT
/4, uses
the value in register CAPREL to perform a reload on underflow. This means, the value in register CAPREL
represents the time between two underflows of timer T6, now measured in timer T6 increments. Since (in this
example) timer T6 runs 8 times faster than timer T5, it will underflow 8 times within the time between two
external events. Thus, the underflow signal of timer T6 generates 8 ‘ticks’. Upon each underflow, the interrupt
request line T6IRQ will be activated and bit T6OTL will be toggled. The state of T6OTL may be output on pin
T6OUT. This signal has 8 times more transitions than the signal which is applied to pin CAPIN.
Auxiliary
Timer T5
T5IRQ
Up/Down
Clear
T5SC
Capture
CAPREL
Register
0
1
MUX
CT3
CI
CAPIN
T3IN
T3EUD
Count
Clock
T5CLR
CRIRQ
MCA05412X11
T6SR
Core Timer T6
Clear
T6CLR
Reload
Up/Down
Count
Clock
Toggle Latch
T6OUT
T6IRQ
T6OUF
to T5
Edge
Select
Edge
Select