XC164-16 Datasheet, PDF (37/417 Pages) Infineon Technologies AG – 16-Bit Single-Chip Microcontroller with C166SV2 Core Volume 2 (of 2): Peripheral Units

XC164-16 Derivatives
Peripheral Units (Vol. 2 of 2)
The General Purpose Timer Units
• If both a positive and a negative transition of T3OTL are selected to trigger a reload,
the core timer will be reloaded with the contents of the auxiliary timer each time it
overflows or underflows. This is the standard reload mode (reload on
overflow/underflow).
• If either a positive or a negative transition of T3OTL is selected to trigger a reload, the
core timer will be reloaded with the contents of the auxiliary timer on every second
overflow or underflow.
• Using this “single-transition” mode for both auxiliary timers allows to perform very
flexible Pulse Width Modulation (PWM). One of the auxiliary timers is programmed to
reload the core timer on a positive transition of T3OTL, the other is programmed for
a reload on a negative transition of T3OTL. With this combination the core timer is
alternately reloaded from the two auxiliary timers.
Figure 14-17 shows an example for the generation of a PWM signal using the “single-
transition” reload mechanism. T2 defines the high time of the PWM signal (reloaded on
positive transitions) and T4 defines the low time of the PWM signal (reloaded on negative
transitions). The PWM signal can be output on pin T3OUT if T3OE = 1. With this method,
the high and low time of the PWM signal can be varied in a wide range.
Note: The output toggle latch T3OTL is accessible via software and may be changed, if
required, to modify the PWM signal.
However, this will NOT trigger the reloading of T3.
User’s Manual
GPT_X41, V2.0
14-24
V2.1, 2004-03