Owner's manual

Preliminary
APR6016 Data Sheet
Voice Recording & Playback Device Page 13
Revision 1.0
Playing Back Audio Data
When a
SET_PLAY
or
PLAY
command is issued the device
will be
g
in samplin
g
the data in the specified sector and pro-
duce a resultant output on the AUDOUT, ANAOUT-, and
ANAOUT+ pins. After half the sector is used the SAC pin will
drop low to indicate that a new command can be accepted.
The device will accept commands as lon
g
as the SAC pin
remains low. An
y
command received after the SAC returns
hi
g
h will be
q
ueued up and executed durin
g
the next SAC
c
y
cle.
Fi
g
ure 14 shows a t
y
pical timin
g
dia
g
ram and OpCode
se
q
uence for a pla
y
back operation. The
SET_PLAY
com-
mand be
g
ins pla
y
back at the specified memor
y
location after
T
aplay
time has passed. Some time later the low
g
oin
g
ed
g
e
on the SAC pin alerts the host processor that half of the first
sector has been pla
y
ed back. The host processor responds
b
y
issuin
g
a
PLAY
command durin
g
the SAC low time. The
PLAY
command instructs the APR6016 to continue pla
y
back
of the sector immediatel
y
followin
g
the current sector. When
the first sector has been pla
y
ed back the device
j
umps to the
next sector and returns the SAC si
g
nal to a hi
g
h state to indi-
cate that the second sector is now bein
g
pla
y
ed. At this point
the host processor decides to issue a
STOP
command durin
g
the next available SAC low time. The device follows the
STOP
command and terminates pla
y
back after TS
aplay
. The
/BUSY pin indicates when actual pla
y
back is takin
g
place.
Figure 14 Typical Playback Sequence
Handshaking signals
Several si
g
nals are included in the device that allow for hand-
shakin
g
. These si
g
nals can simplif
y
messa
g
e mana
g
ement
si
g
nificantl
y
dependin
g
on the messa
g
e mana
g
ement
scheme used.
The /INT si
g
nal can be used to
g
enerate interrupts to the pro-
cessor when attention is re
q
uired b
y
the APR6016 This pin is
normall
y
hi
g
h and
g
oes low when an interrupt is re
q
uested.
An interrupt is
g
enerated whenever a EOD or Overflow
occurs.
The SAC si
g
nal is used to determine when the device is
nearin
g
the end of the current memor
y
se
g
ment durin
g
either
a record, pla
y
or forward operation. The SAC si
g
nal is in a
normall
y
hi
g
h state. The si
g
nal
g
oes low after half the cur-
rentl
y
active se
g
ment has been pla
y
ed or recorded. The si
g
-
nal returns to a hi
g
h state after the entire se
g
ment has been
pla
y
ed or recorded. The microprocessor should sense the
low ed
g
e of the SAC si
g
nal as an indicator that the next se
g
-
/CS
SCLK
DI
T
aplay
TS
aplay
SET_PLAY
STOP
SAC
ANAOUT+
ANAOUT-
ANAOUT
/BUSY
Note: Command timing is not to scale
PLAY