MLX90621

16x4 IR array

Datasheet

39001090621

Page 31 of 44

Datasheet IR16x4

Rev 3.0

15 September 2016

Communication to IR array

9.4.

Start measurement command

9.4.1.

Opcode – 0x01 (LSByte), 0x08 (MSByte).

This command is used to start measurement cycle in step mode.

Figure 22: Start measurement command structure

Read command

9.4.2.

Opcode – 0x02.

The read command is used to read measurement, configuration and other data from the chip to the external master.

The read command has the following parameters:

-

Start address – 8bits. Address in the chip address space (0 to 255). It is the address of the first word read.

-

Address step – 8bits. On every read word the next address is formed by adding the address step to the current

address.

-

Number of reads – 8bits. Number of the words to be read.

Different combinations are possible in order to read all, one line, one column, one exact pixel of the IR or Ta sensors.

They are summarized in the table below:

Sensors read

Start address

Address step

Number of reads

All IR

0x00

0x01

0x40

One line IR(i)

i

0x04

0x10

One column IR(j)

j*0x04

0x01

0x04

One pixel IR(i,j)

I + j*0x04

0x00

0x01

Table 20 RAM readout options

Figure 23: RAM readout command structure

S

T

A

R

T

A

C

K

0

Slave address

A

C

K

Start Meas

LSByte Opcode

S

T

O

P

A

C

K

Start Meas

MSByte Opcode

S

T

A

R

T

A

C

K

0

Slave address

A

C

K

Read Opcode

S

T

O

P

A

C

K

A

C

K

A

C

K

Start address

parameter

Address step

parameter

Number reads

parameter

S

T

A

R

T

A

C

K

A

C

K

Read Word0

LSByte

Slave address

1

A

C

K

Read Word0

MSByte

A

C

K

Read WordN

LSByte

A

C

K

Read WordN

MSByte

Read N 16bit words