TSL3301

102 × 1 LINEAR OPTICAL SENSOR ARRAY

WITH ANALOGTODIGITAL CONVERTER

TAOS026 – FEBRUARY 2001

8

www.taosinc.com

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Copyright

E 2001, TAOS Inc.

OPERATION

Initialization Sequence

After powering on the device, a minimum of 10 clocks with SDIN held high must be received by the TSL3301

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

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 0x40 are the only two legitimate user programmable values for the single-chip version of the

TSL3301. Other values may put the device into a non-operational mode.

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

SAMPLEInt, READHold, 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 be used

to clock commands or data into or out of the device.