User Manual

Application Note
SMBus communication with MLX90614
390119061402 Page 13 of 32 Jan-2008
Rev 004
used – MD when the master device is making acknowledge; SD when the slave device is
making acknowledge). For other timings see Electrical characteristics of SMBus devices above.
Fig.8:MLX90614 specific timings
In Table 5 are given the values of the specific timings.
Table 5
Symbol Parameter Min Max Units Comments
t
REQ
SMBus Request 2 ms
t
suac
(MD) 0.5 1 µs
t
suac
(SD) 1.5 2 µs
t
hdac
(MD) 1.5 2 µs
t
hdac
(SD) 0.5 1 µs
6.3 Detailed Communication description
Table 6 describes commands needed for communication with MLX90614.
Table 6
Command Description
000x xxxx* RAM Access
001x xxxx* EEPROM Access
1
111
0000*
*
Read Flags
1111 1111
Enter SLEEP mode
Note *: The xxxxx is the address of the cell that has to be accessed. Read/Write is selected via the Read/Write bit
(refer to Fig. 3).
Note**: Behaves like read command. The MLX90614 returns PEC after 16 bits data of which only 4 are meaningful
and if the MD wants it, it can stop the communication after the first byte. The difference between read and read flags
is that the latter does not have a repeated start bit.