Modes of Operation
15-18
ADSP-BF537 Blackfin Processor Hardware Reference
the
TOVL_ERRx
flags. Pulse width values greater than the period value are
not recommended. Similarly,
TIMERx_WIDTH
=
0
is not a valid operation.
Duty cycles of 0% are not supported.
To generate the maximum frequency on the
TMRx
output pin, set the
period value to 2 and the pulse width to 1. This makes
TMRx
toggle each
SCLK
clock, producing a duty cycle of 50%. The period may be pro-
grammed to any value from 2 to (2
32
– 1), inclusive. The pulse width may
be programmed to any value from 1 to (period – 1), inclusive.
PULSE_HI Toggle Mode
The waveform produced in
PWM_OUT
mode with
PERIOD_CNT
= 1 normally
has a fixed assertion time and a programmable deassertion time (via the
TIMERx_WIDTH
register). When two timers are running synchronously by
the same period settings, the pulses are aligned to the asserting edge as
shown in
.
The
TOGGLE_HI
mode enables control of the timing of both the asserting
and deasserting edges of the output waveform produced. The phase
between the asserting edges of two timer outputs is programmable. The
effective state of the
PULSE_HI
bit alternates every period. The adjacent
Figure 15-7. Timers With Pulses Aligned to Asserting Edge
TMR0
TMR1
PERIOD 1
TMR2
TOGGLE_HI = 0
PULSE_HI = 1
TOGGLE_HI = 0
PULSE_HI = 1
TOGGLE_HI = 0
PULSE_HI = 1
TIMER
ENABLE
ACTIVE
HIGH
ACTIVE
HIGH
ACTIVE
HIGH
Summary of Contents for Blackfin ADSP-BF537
Page 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Page 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...