User guide

Voice Recording & Playback Device Page 11
Revision 2.1
Reading Digital Data
Digital data is read from the device using the
DIG_READ
command. To read data you must send a
DIG_READ
com-
mand immediatel
y followed by 3012 don’t care bits during the
same /CS c
ycle. The data previously stored in the specified
sector will be
gin to appear on the DO pin after the current
device status or SID and four buffer bits. The next 3004 bits
are the previousl
y stored data. The first bit shifted out is the
first bit that was written. The last bit shifted out is the last bit
that was written. There are four random don’t care bits follow-
in
g the 3004 bits of user data.
An incomplete read of the sector is allowed. An incomplete
read is defined a a read with less than 3032 clock c
ycles. All
incomplete read c
ycles require one extra SCLK cycle after
the /CS si
gnal returns high.
Fi
gure 12 shows a timing diagram which describes the entire
process for a complete sector read. All timin
g with the excep-
tion of T
pSCLK
should adhere to the specifications given in
Fi
gure 4 and Figure 7. The T
pSCLK
specification is replaced
b
y the DT
pSCLK
when reading digital data.
Figure 12Reading Digital Data
/CS
SCLK
DI
DO
DIG_READ COMMAND
3012 don’t Care Bits
Total 3032 clock cycles
SID or CDS
3004 bits of previousl
y stored data
XXX
X
XXX
X
APR6008