Clock control
Counter
Select
DTFALLT
DTRISET
=0
Original PWM (TIM0_CCx_pre)
HFPERCLK
TIMERn
Primary output (TIM0_CCx)
Complementary Output (TIM0_CDTIx)
Figure 18.41. TIMER Overview of Dead-Time Insertion Block for a Single PWM channel
The DTI unit is enabled by setting DTEN in TIMER0_DTCTRL. In addition to providing the complementary outputs, the DTI unit then
also overrides the compare match outputs from the timer.
The DTI unit gives the rising edges of the PWM outputs and the rising edges of the complementary PWM outputs a configurable time
delay. By doing this, the DTI unit introduces a dead-time where both the primary and complementary outputs in a pair are inactive as
seen in
Figure 18.42 TIMER Polarity of Both Signals are Set as Active-High on page 597
.
Original PWM
TIM0_CC0
TIM0_CDTI0
dt1
dt2
Figure 18.42. TIMER Polarity of Both Signals are Set as Active-High
Dead-time is specified individually for the rising and falling edge of the original PWM. These values are shared across all the three
PWM channels of the DTI unit. A single prescaler value is provided for the DTI unit, meaning that both the rising and falling edge dead-
times share prescaler value. The prescaler divides the HFPERCLK
TIMERn
by a configurable factor between 1 and 1024, which is set in
the DTPRESC field in TIMER0_DTTIME. The rising and falling edge dead-times are configured in DTRISET and DTFALLT in TIM-
ER0_DTTIME to any number between 1-64 HFPERCLK
TIMER0
cycles.
The DTAR and DTFATS bits in TIMER0_DTCTRL control the DTI output behavior when the timer stops. By default the DTI block stops
when the timer is stopped. Setting the DTAR bit will cause the DTI to output on channel 0 to continue when the timer is stopped. DTAR
effects only channel 0. See
18.3.3.2 PRS Channel as a Source
for an example of when this can be used. While in this mode the undivi-
ded HFPERCLK_TIMER0 (DTPRESC=0) is always used regardless of programmed DTPRESC value in TIMER0_DTTIME. This means
that rise and fall dead times are calculated assuming DTPRESC = 0.
When the timer stops DTI outputs are frozen by default, preserving their last state. To allow the outputs to go to a safe state as pro-
grammed in the DTFA field of TIMER0_DTFC register and set the DTFATS bitfield in the TIMER0_DTCTRL reg. Note that when DTAR
is also set, DTAR has priority over DTFATS for DTI channel 0 output.
EFM32JG1 Reference Manual
TIMER - Timer/Counter
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