TSL3301−LF
102
×
1 LINEAR OPTICAL SENSOR ARRAY
WITH ANALOG-TO-DIGITAL CONVERTER
TAOS0078C
−
APRIL 2007
OPERATION
Initialization Sequence
After powering on the device, a minimum of 10 clocks with SDIN held high must be received by the TSL3301−LF
to clear the receiver logic so that a start bit will be detected correctly. The control logic may then be cleared by
either issuing an
IRESET
command (break character) or 3
RESET
(0x1b) commands. An additional 30 clocks
must be received by the device to assure the state of SDOUT.
Sleep Mode
The device can be put into a power down or sleep mode by writing a 0x10 to the mode register. This turns off
all the analog circuitry on the chip. Normal operation is restored by writing a 0x00 to the mode register. The
analog circuitry will require a minimum of 1 millisecond to recover from the sleep mode.
†
Note that putting the device in the sleep mode does not affect the logic states of the machine. If, for example,
a
READPixel
command is issued, the device will respond but the resulting data will be meaningless. Also note
that 0x00 and 0x10 are the only two legitimate user programmable values for the single-chip version of the
TSL3301−LF. Other values may put the device into a non-operational mode.
†
For minimum sleep mode current consumption, voltage levels on logic inputs must be at either V
DD
or ground.
Imaging
After powering up the device and completing the initialization sequence, it is necessary to allow a minimum of
1 millisecond for the internal analog circuitry to settle. This delay is also required when coming out of the sleep
mode.
Issuing a
STARInt
(0x08) command will release the pixel integrators from the reset state. After an appropriate
delay to integrate the image, the pixel data may be sampled by issuing a
SAMPLEInt
(0x10) command and then
read out by issuing a
READPixel
(0x02) command.
A
STARTInt
command can be issued anytime after the
SAMPLEInt
command is issued to start another cycle.
Thus, it is possible to be reading out one sample while integrating the next. However, the sampled data from
the previous
SAMPLEInt
must be completely read out before the next
SAMPLEInt
command is issued.
The compound commands
READHold
(0x12) and
READHoldNStart
((0x16) are shortcut commands to simplify
the imaging sequence.
It is important to note that a pixel reset sequence is initiated with the receipt of a
STARTInt
or
READHoldNStart
command. The next integration sequence cannot start until the pixel reset sequence has been completed, which
requires 22 clocks
AFTER
the receipt of one of these commands. These clocks can also be used to clock
commands or data into or out of the device.
The
LUMENOLOGY
r
Company
r
r
Copyright
E
2007, TAOS Inc.
www.taosinc.com
9
TAOS [ TEXAS ADVANCED OPTOELECTRONIC SOLUTIONS ]
