Rainbow Electronics APR6008 - Manual (Page 10)

Page 10 Voice Recording & Playback Device
Revision 2.1
Writing Digital Data
Digital data is written into the device using the DIG_WRITE
command. No mixing of analog data and digital data within a
sector is possible. Sectors 0 through 9 are tested and guar-
anteed for digital storage. Other sectors, with the exception of
sector 639, can store data but have not been tested, and are
thus not guaranteed to provide 100% good bits. This can be
managed with error correction or forward check-before-store
methods. Issuing a
DIG_ERASE command on sector 639 will
cause data throughout all sectors to be lost.
A sector must be erased, using the DIG_ERASE command,
before digital data can be written to it. This requirement is
necessary whether analog data or digital data was previously
stored in the sector. A sector should not be erased more than
once between analog or digital write operations. Executing
multiple erase operations on a sector will permanently dam-
age the sector. A sector can be reallocated to either analog
storage or digital storage at any time.
The process of storing digital data begins by sending a
DIG_WRITE command. The DIG_WRITE command is fol-
lowed immediately by four buffer bits. These bits will not be
stored in the array and must be considered don’t care bits.
Immediately following the four buffer bits should be the data
that you wish to store. All 3004 bits must be stored. Four
additional buffer bits must be clocked into the device follow-
ing the stored data. These bits will not be stored in the array
and must be considered don’t care bits. Ending a digital write
command early will permanently damage the sector.
The DO pin will clock out the normal 20 bit CDS followed by
five don’t care bits, a copy of the 3004 data bits, and finally
three don’t care bits.
Figure 11 shows a timing diagram which describes the digital
storage process. All timing with the exception of T
pSCLK
should adhere to the specifications given in Figure 4 and Fig-
ure 7. The T
pSCLK
specification is replaced by the DT
pSCLK
when storing digital data.
Note: The DIG_ERASE command should not be used before
storing analog data. The device will perform its own internal
erase before analog storage.
Figure 11 does not show the DIG_ERASE command which
must be executed on a sector before digital data can be
stored.
Figure 11 Writing Digital Data
/C S
SC LK
D I
D O CDS Copy of the input data (delayed one clock cycle)
Four Don’t Care Bits
Total 3032 clock cycles
X X X X X X X X
DIG_WRITECOMMAND 3004 bits of data to be stored X X X X X X X X
APR6008