https://github.com/watterott/TSL45315-Breakout/blob/master/src/TSL45315.ino

{{:tek:tsl4531-a.pdf|}}

#define I2C_ADDR (0x29) 0x39 ?

#define REG_CONTROL 0x00
#define REG_CONFIG 0x01
#define REG_DATALOW 0x04
#define REG_DATAHIGH 0x05
#define REG_ID 0x0A

ecrire 0x80
ecrire 0x03

lire 2 registres  0x04 0x05

The ADC output is a 16-bit number that is directly proportional to the value that approximates the human eye
response in the commonly used illuminance unit of lux. The light level can be calculated using the following
expression.
<code>
Light Level (lux) = MULTIPLIER × [ (DATAHIGH << 8) + DATALOW ]
Where:     MULTIPLIER = 1 for TCNTRL = 00 (Tint = 400 ms),
       MULTIPLIER = 2 for TCNTRL = 01 (Tint = 200 ms), and
       MULTIPLIER = 4 for TCNTRL = 10 (Tint = 100 ms), and
                  << 8 indicates a logical 8-bit shift left operation, and
       TCNTRL is a 2-bit field in the configuration register (0x01)
Example:
           MULTIPLIER = 1
           DATALOW = 0x9C
           DATAHIGH = 0x63
                         1 × [ (DATAHIGH << 8) + DATALOW] lux
           Illuminance =
                                =  (0x63 << 8) + 0x9C lux
                                =  0x639C lux
                                =  25,500 lux
</code>

http://code.google.com/p/webiopi/wiki/TSL4531