Modes of Operation
10-32
ADSP-BF50x Blackfin Processor Hardware Reference
Both
TIMIL
and
TOVF_ERR
are sticky bits, and software must explicitly clear
them. If the timer overflowed and
PERIOD_CNT
= 1, neither the
TIMER_PERIOD
nor the
TIMER_WIDTH
register were updated. If the timer
overflowed and
PERIOD_CNT
= 0, the
TIMER_PERIOD
and
TIMER_WIDTH
regis-
ters were updated only if a trailing edge was detected at a previous
measurement report.
Software can count the number of error report interrupts between mea-
surement report interrupts to measure input signal periods longer than
0xFFFF FFFF. Each error report interrupt adds a full 2
32
SCLK
counts to
the total for the period, but the width is ambiguous. For example, in
Figure 10-13
the period is 0x1 0000 0004 but the pulse width could be
either 0x0 0000 0002 or 0x1 0000 0002.
The waveform applied to the
TMR
pin is not required to have a 50% duty
cycle, but the minimum
TMR
pin low time is one
SCLK
period and the min-
imum
TMR
pin high time is one
SCLK
period. This implies the maximum
TMR
pin input frequency is
SCLK
/2 with a 50% duty cycle. Under these
conditions, the
WDTH_CAP
mode timer would measure Period = 2 and
Pulse Width = 1.
Autobaud Mode
On some devices, in WDTH_CAP mode, some of the timers can provide
autobaud detection for the Universal Asynchronous Receiver/Transmitter
(UART) interface(s). The TIN_SEL bit in the TIMER_CONFIG register
causes the timer to sample the TACI pin instead of the TMR pin when
enabled for WDTH_CAP mode. Autobaud detection can be used for ini-
tial bit rate negotiations as well as for detection of bit rate drifts while the
interface is in operation.
Summary of Contents for EZ-KIT Lite ADSP-BF506F
Page 50: ...Contents l ADSP BF50x Blackfin Processor Hardware Reference ...
Page 92: ...Development Tools 1 30 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 110: ...Interface Overview 3 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 236: ...Internal Flash Memory Control Registers 6 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 650: ...Programming Examples 15 56 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 804: ...Programming Examples 17 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1194: ...Programming Examples 24 90 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1256: ...ACM Registers A 50 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1264: ...Boundary Scan Architecture B 8 ADSP BF50x Blackfin Processor Hardware Reference ...