Description of Operation
15-10
ADSP-BF537 Blackfin Processor Hardware Reference
Illegal States
Every timer features an error detection circuit. It handles overflow situa-
tions but also performs pulse width vs. period plausibility checks. Errors
are reported by the
TOVF_ERRx
bits in the
TIMER_STATUS
register and the
ERR_TYP
bit field in the individual
TIMERx_CONFIG
provides a summary of error conditions, by using these terms:
•
Startup
. The first clock period during which the timer counter is
running after the timer is enabled by writing
TIMER_ENABLE
.
•
Rollover
. The time when the current count matches the value in
TIMERx_PERIOD
and the counter is reloaded with the value 1.
•
Overflow
. The timer counter was incremented instead of doing a
rollover when it was holding the maximum possible count value of
0xFFFF FFFF. The counter does not have a large enough range to
express the next greater value and so erroneously loads a new value
of 0x0000 0000.
•
Unchanged
. No new error.
• When
ERR_TYP
is unchanged, it displays the previously
reported error code or 00 if there has been no error since
this timer was enabled.
• When
TOVF_ERR
is unchanged, it reads 0 if there has been no
error since this timer was enabled, or if software has per-
formed a W1C to clear any previous error. If a previous
error has not been acknowledged by software,
TOVF_ERR
reads 1.
Software should read
TOVF_ERR
to check for an error. If
TOVF_ERR
is set,
software can then read
ERR_TYP
for more information. Once detected,
software should write 1 to clear
TOVF_ERR
to acknowledge the error.
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 ...