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

13

LM3535

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SNVS598B – AUGUST 2010 – REVISED MARCH 2018

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Programming (continued)

7.5.1.3 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.

After the START condition, the I2C master sends a chip address. This address is seven bits long followed by an

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 19. 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

7.5.1.4 I2C Compatible Chip Address

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

7.5.1.5 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 Register

0x30

0000 0000 (0x00)

ALS Zone Readback

0x40

1111 0000 (0xF0)

ALS Control Register

0x50

0000 0011 (0x03)

ALS Resistor Register

0x51

0000 0000 (0x00)

ALS Zone Boundary #0

0x60

0011 0011 (0x33)

ALS Zone Boundary #1

0x61

0110 0110 (0x66)

ALS Zone Boundary #2

0x62

1001 1001 (0x99)

ALS Zone Boundary #3

0x63

1100 1100 (0xCC)

ALS Brightness Zone #1

0x70

1001 1001 (0x99)

ALS Brightness Zone #2

0x71

1011 0110 (0xB6)

ALS Brightness Zone #3

0x72

1100 1100 (0xCC)

ALS Brightness Zone #4

0x73

1110 0110 (0xE6)

ALS Brightness Zone #5

0x74

1111 1111 (0xFF)

Group A Brightness Control Register 0xA0

1000 0000 (0x80)

Group B Brightness Control Register 0xB0

1100 0000 (0xC0)

Group C Brightness Control Register 0xC0

1111 1000 (0xF8)