High-resolution timer (HRTIM) RM0440
852/2126 RM0440 Rev 4
f
DTG
: deadtime generator clock. For convenience, only the t
DTG
period (t
DTG
=
1/f
DTG
) is used in this document.
f
CHPFRQ
: chopper stage clock source.
f
1STPW
: clock source defining the length of the initial pulse in chopper mode. For
convenience, only the t
1STPW
period (t
1STPW
= 1/f
1STPW
) is used in this
document.
f
BRST
: burst mode controller counter clock.
f
SAMPLING
: clock needed to sample the fault or the external events inputs.
f
FLTS
: clock derived from f
HRTIM
which is used as a source for
f
SAMPLING to filter fault events.
f
EEVS
: clock derived from f
HRTIM
which is used as a source for
f
SAMPLING to filter external events.
Timer clock and prescaler
Each timer in the HRTIM has its own individual clock prescaler, which allows you to adjust
the timer resolution (see Table 213).
The high-resolution is available for edge positioning, PWM period adjustment and externally
triggered pulse duration.
The high-resolution is not available for the following features
• Timer counter read and write accesses
• Capture unit
For clock prescaling ratios below 32 (CKPSC[2:0] < 5), the least significant bits of the
counter and capture registers are not significant. The least significant bits cannot be written
(counter register only) and return 0 when read.
For instance, if CKPSC[2:0] = 2 (prescaling by 4), writing 0xFFFF into the counter register
yields an effective value of 0xFFF8. Conversely, any counter value between 0xFFFF and
0xFFF8 is read as 0xFFF8.
Table 213. Timer resolution and min. PWM frequency
for f
HRTIM
= 170 MHz
CKPSC[2:0]
Prescal-
ing ratio
f
HRCK
equivalent frequency
Resolution Min PWM frequency
000 1 170 x 32 MHz = 5.44 GHz 184 ps 83.0 kHz
001 2 170 x 16 MHz = 2.72 GHz 368 ps 41.5 kHz
010 4 170 x 8 MHz = 1.36 GHz 735 ps 20.8 kHz
011 8 170 x 4 MHz = 680 MHz 1.47 ns 10.4 kHz
100 16 170 x 2 MHz = 340 MHz 2.94 ns 5.19 kHz
101 32 170 MHz 5.88 ns 2.59 kHz
110 64 170/2 MHz = 85 MHz 11.76 ns 1.30 kHz
111 128 170/4 MHz = 42.5 MHz 23.53 ns 0.65 kHz
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