C167CS datasheet(265/517 Pages) INFINEON

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C167CS

Derivatives

The General Purpose Timer Units

User’s Manual

10-37

V2.0, 2000-07

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.

fCPU/32. The external events are applied to pin CAPIN. When an external event occurs,

the timer T5 contents are latched into register CAPREL, and timer T5 is cleared

(T5CLR = ‘1’). Thus, register CAPREL 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.

fCPU / 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 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 flag T6IR will be set 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.

The underflow signal of timer T6 can furthermore be used to clock one or more of the

timers of the CAPCOM units, which gives the user the possibility to set compare events

based on a finer resolution than that of the external events.

C167CS Datasheet(PDF) 265 Page - Infineon Technologies AG