TSL2301

102 × 1 LINEAR OPTICAL SENSOR ARRAY

WITH ANALOGTODIGITAL CONVERTER

TAOS007 – JULY 2000

7

www.taosinc.com

t

t

Copyright

E 2000, TAOS Inc.

Reset Commands

Reset commands are used to put the TSL2301 into a known state.

IRESET – Interface Initialization

Encoding: Break Character

IRESET initializes the internal state machine that keeps track of which command bytes have been received.

This command should be first and given only once after power-up to synchronize TSL2301’s command

interpreter.

RESET – Main Reset

Encoding: 0x1b: <0001_1011>

RESET resets most of the internal control logic of the TSL2301 and any READPixel command currently in

progress is aborted.

RESET puts the pixel integrators into the auto-zero/reset state. Any values that were being

held in the array’s sample/hold circuits are lost.

NOTE:

On power up of the TSL2301, it is necessary to hold SDIN high for 30 clocks before initiating a reset

command. In addition, to fully reset the device, it is recommended that 3 consecutive RESET

commands be issued as part of the power up routine.

NOTE:

The value on the SDOUT pin is not guaranteed from the time power is applied until 30 clocks after

the first RESET command is issued.

Pixel Action Commands

Pixel action commands allow the user to control pixel integration and reading of pixel data.

STARTInt – Start Integration

Encoding: 0x08: <0000_1000>

STARTInt causes each pixel to leave the reset state and to start integrating. The actual execution of STARTInt

is delayed 20 clocks until the auto-zero cycle of the pixels has been completed.

SAMPLEInt – Stop Integration

Encoding: 0x10: <0001_0000>

SAMPLEInt causes each pixel to store its integrator’s contents into a sample and hold circuit. Also, the Integrator

is returned to the reset state.

READPixel – Read Pixel Data

Encoding: 0x02: <0000_0010>

READPixel causes the sampled value of each pixel to be converted to an 8-bit digital value that is clocked out

on the

SDOUT pin. The LSB is the first data bit, which is preceded by a START bit (logic 0) and followed by a

STOP bit (logic 1). Each pixel in the device is presented on

SDOUT starting from pixel 00 and completes with

pixel 101. It takes 20 clocks before the first pixel is available to be read and 10 clocks per pixel thereafter until

all pixels are output.

Gain and offset registers are used to adjust the ADC converter to maximize dynamic range and should be

programmed prior to invoking the

READPixel command.