Zero Marker Events; Capturing Timing Information; Capturing Time Interval Between Successive Counter Events - Analog Devices ADSP-BF506F Hardware Reference Manual

Functional Description

Zero Marker Events

There are three status bits
marker events, as described in
page 13-9. Each of these events can optionally generate an interrupt
request, if enabled by the corresponding
the
CNT_IMASK

Capturing Timing Information

To calculate speed, many applications may wish to measure the time
between two count events—in addition to accurately counting encoder
pulses. For more accuracy, particularly at very low speeds, it is also neces-
sary to obtain the time that has elapsed since the last count event. This
additional information allows for estimating how much the GP counter
has advanced since the last counter event.
For this purpose, the GP counter has an internal signal that connects to
the alternate capture input (
tional in all modes, with the exception of the timed direction mode. Refer
to "Internal Interfaces" in
mation regarding which GP timer(s) are associated with which GP
counter module(s) for your device.
In order to use the timing measurements, the associated GP timer must be
used in the
WDTH_CAP
ting the
TIN_SEL
information about the GP timers and their operating modes, refer to the
General-Purpose Timer chapter.
Capturing Time Interval Between
Successive Counter Events
When the only timing information of interest is the interval between suc-
cessive count events, the associated timer should be programmed in
mode with
WDTH_CAP
13-14
,
CZMII
"Zero Marker (Push Button) Operation" on
register.
TACIx
Chapter 9, "General-Purpose Ports"
mode. The alternate capture input is selected by set-
bit in the GP timer's
= 1,
PULSE_HI
ADSP-BF50x Blackfin Processor Hardware Reference
and
CZMEII CZMZII
,
CZMIE CZMEIE
) of one of the GP timers. It is func-
TIMER_CONFIG
= 1 and
PERIOD_CNT
associated with zero
and bits in
CZMZIE
for infor-
register. For more
= 1.
TIN_SEL