PPI Registers
7-34
ADSP-BF537 Blackfin Processor Hardware Reference
PPI_DELAY Register
The
PPI_DELAY
, can be used in all configu-
rations except ITU-R 656 modes and GP modes with 0 frame syncs. It
contains a count of how many
PPI_CLK
cycles to delay after assertion of
PPI_FS1
before starting to read in or write out data.
L
Note in TX modes using at least one frame sync, there is a
one-cycle delay beyond what is specified in the
PPI_DELAY
register.
PPI_COUNT Register
The
PPI_COUNT
register, shown in
“RX mode with 0 frame syncs, external trigger” and “TX mode with 0
frame syncs.” For RX modes, this register holds the number of samples to
read into the PPI per line, minus one. For TX modes, it holds the number
of samples to write out through the PPI per line, minus one. The register
itself does not actually decrement with each transfer. Thus, at the begin-
ning of a new line of data, there is no need to rewrite the value of this
register. For example, to receive or transmit 100 samples through the PPI,
set
PPI_COUNT
to 99.
a
Take care to ensure that the number of samples programmed into
PPI_COUNT
is in keeping with the number of samples expected dur-
ing the “horizontal” interval specified by
PPI_FS1
.
Figure 7-15. Delay Count Register
Delay Count Register (PPI_DELAY)
15 14
13 12 11 10
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
PPI_DELAY[15:0]
Reset = 0x0000
Number of PPI_CLK cycles to
delay after assertion of
PPI_FS1 before latching in or
sending out data
0xFFC0 100C
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 ...