C167CS datasheet(232/517 Pages) INFINEON

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C167CS

Derivatives

The General Purpose Timer Units

User’s Manual

10-4

V2.0, 2000-07

Timer 3 Run Bit

The timer can be started or stopped by software through bit T3R (Timer T3 Run Bit). If

T3R = ‘0’, the timer stops. Setting T3R to ‘1’ will start the timer.In gated timer mode, the

timer will only run if T3R = ‘1’ and the gate is active (high or low, as programmed).

Count Direction Control

The count direction of the core timer can be controlled either by software or by the

external input pin T3EUD (Timer T3 External Up/Down Control Input), which is the

alternate input function of port pin P3.4. These options are selected by bits T3UD and

T3UDE in control register T3CON. When the up/down control is done by software (bit

T3UDE = ‘0’), the count direction can be altered by setting or clearing bit T3UD. When

T3UDE = ‘1’, pin T3EUD is selected to be the controlling source of the count direction.

However, bit T3UD can still be used to reverse the actual count direction, as shown in

Table 10-1. If T3UD = ‘0’ and pin T3EUD shows a low level, the timer is counting up.

With a high level at T3EUD the timer is counting down. If T3UD = ‘1’, a high level at pin

T3EUD specifies counting up, and a low level specifies counting down. The count

direction can be changed regardless of whether the timer is running or not.

When pin T3EUD/P3.4 is used as external count direction control input, it must be

configured as input, i.e. its corresponding direction control bit DP3.4 must be set to ‘0’.

Note: The direction control works the same for core timer T3 and for auxiliary timers T2

and T4. Therefore the pins and bits are named Tx …

Table 10-1

GPT1 Core Timer T3 Count Direction Control

Pin TxEUD

Bit TxUDE

Bit TxUD

Count Direction

Count Up

Count Down

Count Up

Count Down

Count Up

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