start

msb Chip Address lsb

w

ack

msb Register Add lsb

ack

msb

DATA

lsb

ack

stop

ack from slave

ack from slave

ack from slave

SCL

SDIO

start

Id = 38h

w

ack

addr = 10h

ack

ack

DGGUHVV K¶3F data

stop

SDIO

SCL

P

STO

condition

S

P

LM3535

www.ti.com

SNVS598A – AUGUST 2010 – REVISED MAY 2013

START AND STOP CONDITIONS

defined as SDIO signal transitioning from HIGH to LOW while SCL line is HIGH. A STOP condition is defined as

START conditions are equivalent, function-wise.

Figure 28. Start and Stop Conditions

TRANSFERRING DATA

Every byte put on the SDIO line must be eight bits long, with the most significant bit (MSB) transferred first. Each

byte of data has to be followed by an acknowledge bit. The acknowledge related clock pulse is generated by the

master. The master releases the SDIO line (HIGH) during the acknowledge clock pulse. The LM3535 pulls down

the SDIO line during the 9th clock pulse, signifying an acknowledge. The LM3535 generates an acknowledge

after each byte is received. There is no acknowledge created after data is read from the LM3535.

eighth bit which is a data direction bit (R/W). The LM3535 7-bit address is 38h. For the eighth bit, a “0” indicates

a WRITE and a “1” indicates a READ. The second byte selects the register to which the data will be written. The

third byte contains data to write to the selected register.

Figure 29. Write Cycle

w = write (SDIO = "0")

r = read (SDIO = "1")

ack = acknowledge (SDIO pulled down by either master or slave)

id = chip address, 38h for LM3535

The 7-bit chip address for LM3535 is 111000, or 0x38.

INTERNAL REGISTERS OF LM3535

Register

Internal Hex Address

Power On Value

Diode Enable Register

0x10

0000 0000 (0x00)

Configuration Register

0x20

0000 0000 (0x00)

Options

0x30

0000 0000 (0x00)

Register

ALS Zone Readback

0x40

1111 0000 (0xF0)

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