ADSP-BF50x Blackfin Processor Hardware Reference
13-11
General-Purpose Counter
•
Boundary-zero mode
–This mode is similar to the boundary-com-
pare mode. In addition to setting the status bits and requesting
interrupts, the counter value in the
CNT_COUNTER
register is also set
to zero.
•
Boundary auto-extend mode
–In this mode, the boundary registers
are modified by hardware whenever the counter value reaches
either of them. The
CNT_MAX
register is loaded with the current
CNT_COUNTER
value if the latter increments beyond the
CNT_MAX
value. Similarly, the
CNT_MIN
register is loaded with the
CNT_COUNTER
value if the latter decrements below the
CNT_MIN
value. This mode may be used to keep track of the widest angle the
wheel ever reported, even if the software did not serve interrupts.
At startup, the application software should set both boundary regis-
ters to the initial
CNT_COUNTER
value. The
MAXCII
and
MINCII
status
bits are still set when the counter value matches the boundary
register.
•
Boundary-capture mode
–In this mode, the
CNT_COUNTER
value is
latched into the
CNT_MIN
register at one detected edge of the
CZM
input pin, and latched into
CNT_MAX
at the opposite edge. If the
CZMINV
bit in the
CNT_CONFIG
register is cleared, a rising edge cap-
tures into
CNT_MIN
and a falling edge into
CNT_MAX
. If the
CZMINV
bit
is set, the edges are inverted. The
MAXCII
and
MINCII
status bits
report the capture event.
The comparison is performed with signed arithmetic. The boundary regis-
ters and the counter value are all treated as signed integer values.
Control and Signaling Events
Eleven events can be signaled to the processor using status information
and optional interrupt requests. The interrupts are enabled by the respec-
tive bits in the
CNT_IMASK
register. Dedicated bits in the
CNT_STATUS
register report events. When an interrupt from the GP counter is
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 ...