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ADSP-BF537 Blackfin Processor Hardware Reference
15-5
General-Purpose Timers
Alternate clock (
TACLKx
) and capture (
TACIx
) inputs are found on port F,
port H and port J. The
TACLKx
pins can alternatively clock the timers in
PWM_OUT
mode.
In
WDTH_CAP
mode, timer 0, timer 1, and timer 6 feature
TACIx
inputs that
can be used for bit rate detection on CAN and UART inputs. The
TACI0
pin connects to the CAN RX input, the
TACI1
pin connects to the UART0
RX input, and the
TACI6
pin connects to the UART1 RX input. The
TACI2
,
TACI3
,
TACI4
,
TACI5
, and
TACI7
pins are not used.
The
TMRCLK
input is another clock input common to all eight timers. The
PPI unit is clocked by the same pin; therefore any of the timers can be
clocked by
PPI_CLK
. Since timer 0 and timer 1 are often used in conjunc-
tion with the PPI, they are internally looped back to the PPI module for
frame sync generation.
In order to enable
TMRCLK
,
PORTF_FER
bit 15 must be set and input enable
for GPIO bit 15 needs to be set in the
PORTxIO_INEN
register.
The timer signals
TMR0
,
TMR1
and
TMR2
are multiplexed with the PPI frame
syncs when the frame syncs are applied externally. PPI modes requiring
only two frame syncs free up
TMR2
for any purpose. Similarly, PPI modes
requiring only one frame sync free up
TMR1
. For details, see
“Parallel Peripheral Interface”
.
L
If the PPI frame syncs are applied externally, timer 0, timer 1, and
timer 2 are still fully functional and can be used for other purposes
not involving the three
TMRx
pins. Timer 0 and timer 1 must not
drive their
TMR0
and
TMR1
pins. If operating in
PWM_OUT
mode, the
OUT_DIS
bit in the
TIMER0_CONFIG
and
TIMER1_CONFIG
registers
must be set.
When clocked internally, the clock source is the processor’s peripheral
clock (
SCLK
). Assuming the peripheral clock is running at 133 MHz, the
maximum period for the timer count is ((2
32
-1) / 133 MHz) =
32.2 seconds.
Содержание Blackfin ADSP-BF537
Страница 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...