Analog Devices ADSP-BF535 Blackfin, Hardware Reference Manual

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Timing Examples
11-70 ADSP-BF535 Blackfin Processor Hardware Reference
These timing examples show the relationships between the signals but are
not scaled to show the actual timing parameters of the processor. Consult
the
ADSP-BF535 Blackfin Embedded Processor Data Sheet for actual timing
parameters and values.
These examples assume a word length of four bits (
SLEN=3
). Framing sig-
nals are active high (
LRFS=0
and
LTFS=0
).
Figure 11-35 through Figure 11-40 show framing for receiving data.
In Figure 11-35 and Figure 11-36 , the normal framing mode is shown for
non-continuous data (any number of
SCK
cycles between words) and con-
tinuous data (no
SCK
cycles between words).
Figure 11-37 and Figure 11-38 show non-continuous and continuous
receiving in the alternate framing mode. These four figures show the input
timing requirement for an externally generated frame sync and also the
output timing characteristic of an internally generated frame sync. Note
the output meets the input timing requirement; therefore, with two
SPORT channels used, one SPORT channel could provide
RFS
for the
other SPORT channel.
Figure 11-39 and Figure 11-40 show the receive operation with normal
framing and alternate framing, respectively, in the unframed mode. A sin-
gle frame sync signal occurs only at the start of the first word, either one
SCK
before the first bit (in normal mode) or at the same time as the first bit
(in alternate mode). This mode is appropriate for multiword bursts (con-
tinuous reception).
Figure 11-41 through Figure 11-46 show framing for transmitting data
and are very similar to Figure 11-35 through Figure 11-40 .
In Figure 11-41 and Figure 11-42 , the normal framing mode is shown for
non-continuous data (any number of
SCK
cycles between words) and con-
tinuous data (no
SCK
cycles between words).