XC164-16 Datasheet, PDF (36/417 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
Auxiliary Timer in Reload Mode
Reload Mode for an auxiliary timer Tx is selected by setting bitfield TxM in the respective
register TxCON to 100_B. In reload mode, the core timer T3 is reloaded with the contents
of an auxiliary timer register, triggered by one of two different signals. The trigger signal
is selected the same way as the clock source for counter mode (see Table 14-5), i.e. a
transition of the auxiliary timer’s input TxIN or the toggle latch T3OTL may trigger the
reload.
Note: When programmed for reload mode, the respective auxiliary timer (T2 or T4) stops
independently of its run flag T2R or T4R.
The timer input pin TxIN must be configured as input if it shall trigger a reload
operation.
f_GPT
T3IN
Operating
Mode
Control
BPS1 TxI
Count
Core Timer T3
Toggle Latch
T3IRQ
T3OUT
T3R
Up/Down
TxIN
0
MUX
1
Edge
Reload
Select
TxIRQ
TxI.2
TxI
Auxiliary
Timer Tx
x = 2, 4
MCA05400
Figure 14-16 GPT1 Auxiliary Timer in Reload Mode
Upon a trigger signal, T3 is loaded with the contents of the respective timer register (T2
or T4) and the respective interrupt request flag (T2IR or T4IR) is set.
Note: When a T3OTL transition is selected for the trigger signal, the interrupt request
flag T3IR will also be set upon a trigger, indicating T3’s overflow or underflow.
Modifications of T3OTL via software will NOT trigger the counter function of T2/T4.
To ensure that a transition of the reload input signal applied to TxIN is recognized
correctly, its level must be held high or low for a minimum number of module clock
cycles, detailed in Section 14.1.5.
The reload mode triggered by the T3 toggle latch can be used in a number of different
configurations. The following functions can be performed, depending on the selected
active transition:
User’s Manual
GPT_X41, V2.0
14-23
V2.1, 2004-03