Timer 1
Timer 3
Timer 3 Ch 1 Output
Timer 1 Ch 1 Output
Timer 3 Ch 0 Compare
AND
Gate
IR OUT
B0358-01
Timer 3 Output
Timer 1 Output
IR Out
Start
T
imers
T
imer3Ch1Compare
T
imer3Ch0Compare
T
imer1Ch1Compare
T0440-01
IR Signal Generation and Learning
Figure 9-7. Block Diagram of Timers in IR-Generation Mode
The timing of the Timer 3 channel 1 output and Timer 1 channel 1 output signals is synchronized such that
no glitches are produced on the IR Out signal.
When the
IRGEN
bit is set, the IR out signal is routed to pins instead of the normal Timer 1 channel 1
output (see also
shows the example of Timer 3 being initialized to a 33% duty cycle (
T3CC0
= 3
×
T3CC1
).
Timer 1 has been initialized to 3.
Figure 9-8. Modulated Waveform Example
To achieve a period of space only,
T1CC1
should be set to 0x00.
9.9.3 Non-Modulated Codes
To generate non-modulated IR codes, Timer 1 is used in modulo mode. The period of the signal is given
by
T1CC0
, and the pulse duration is given by
T1CC1
.
T1CC1
gives the length of the mark period, and
T1CC0
gives the total number of mark and space periods. The compare values are buffered until the timer
hits 0x0000. The compare values must be updated once every period by the DMA or CPU if they are not
to be kept the same.
116
Timer 1 (16-Bit Timer)
SWRU191C
–
April 2009
–
Revised January 2012
Copyright
©
2009
–
2012, Texas Instruments Incorporated