TMD2772

DIGITAL ALS

and PROXIMITY MODULE

TAOS147

E − DECEMBER 2012

26

r

r

Copyright

E 2012, TAOS Inc.

The LUMENOLOGY

r Company

www.taosinc.com

ADC Channel Data Registers (0x14 − 0x17)

should be used with auto increment protocol bits set in the command register. With this operation, when the

lower byte register is read, the upper eight bits are stored in a shadow register, which is read by a subsequent

read to the upper byte. The upper register will read the correct value even if additional ADC integration cycles

end between the reading of the lower and upper registers.

Table 18. ADC Channel Data Registers

REGISTER

ADDRESS

BITS

DESCRIPTION

C0DATA

0x14

7:0

ALS CH0 data low byte

C0DATAH

0x15

7:0

ALS CH0 data high byte

C1DATA

0x16

7:0

ALS CH1 data low byte

C1DATAH

0x17

7:0

ALS CH1 data high byte

Proximity Data Registers (0x18 − 0x19)

should be utilized with auto increment protocol bits set in the command register. With this operation, when the

lower byte register is read, the upper eight bits are stored into a shadow register, which is read by a subsequent

read to the upper byte. The upper register will read the correct value even if the next ADC cycle ends between

the reading of the lower and upper registers.

Table 19.

REGISTER

ADDRESS

BITS

DESCRIPTION

PDATAL

0x18

7:0

Proximity data low byte

PDATAH

0x19

7:0

Proximity data high byte

Proximity Offset Register (0x1E)

The 8-bit proximity offset register provides compensation for proximity offsets caused by device variations,

optical crosstalk, and other environmental factors. Proximity offset is a sign-magnitude value where the sign

bit, bit 7, determines if the offset is negative (bit 7 = 0) or positive (bit 7 = 1). At power up, the register is set to

0x00. The magnitude of the offset compensation depends on the proximity gain (PGAIN), proximity LED drive

strength (PDRIVE), and the number of proximity pulses (PPULSE). Because a number of environmental factors

contribute to proximity offset, this register is best suited for use in an adaptive closed-loop control system. See

available TAOS application notes for proximity offset register application information.

Table 20.

6

75

4

2

31

0

POFFSET

Reset

0x00

MAGNITUDE

SIGN

FIELD

BIT

DESCRIPTION

SIGN

7

Proximity Offset Sign. The offset sign shifts the proximity data negative when equal to 0 and positive when

equal to 1.

MAGNITUDE

6:0

Proximity Offset Magnitude. The offset magnitude shifts the proximity data positive or negative, depending

on the proximity offset sign. The actual amount of the shift depends on the proximity gain (PGAIN), proximity

LED drive strength (PDRIVE), and the number of proximity pulses (PPULSE).