EVB90620 Datasheet, PDF(26/39 Page) Melexis Microelectronic Systems – High precision non-contact temperature measurements

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EVB90620 Datasheet, PDF (26/39 Pages) Melexis Microelectronic Systems – High precision non-contact temperature measurements

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MLX90620

16x4 IR array

9.2 Low level communication protocol

9.2.1 Start / Stop condition

Each communication session is initiated by a START condition and ends with a STOP condition. A

START condition is initiated by a HIGH to LOW transition of the SDA while a STOP is generated by a LOW to

HIGH transition. Both changes must be done while the SCL is HIGH (see the figure)

SCL

SDA

START

STOP

Figure 18: Start / Stop conditions of I2C

9.2.2 Device addressing

The master is addressing the slave device by sending an 7-bit slave address after the START condition. The

first seven bits are dedicated for the address and the 8th is Read/Write (R/W) bit. This bit indicates the

direction of the transfer:

Read (HIGH) means that the master will read the data from the slave

Write (LOW) means that the master will send data to the slave

Mlx90620 is responding to 2 different slave addresses:

1 0 1 0 0 0 0 R/W

for access to internal EEPROM

1 1 0 0 0 0 0 R/W

For access to IR array data

Figure 19: I2C addresses

9.2.3 Acknowledge

During the 9th lock following every byte transfer the transmitter releases the SDA line. The receiver

acknowledges (ACK) receiving the byte by pulling SDA line to low or does not acknowledge (NoACK) by

letting the SDA âHIGHâ.

9.2.4 Low level communication operation

The low level operation communication is based on 8bits (1byte) transmissions. This includes

start/stop event, acknowledgement and errors detection.

3001090620

Rev 4.0

Figure 20: I2C communication

Page 26 of 40

Datasheet IR16x4

19 September 2012

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