MLX90614_15 Datasheet, PDF (17/51 Pages) Melexis Microelectronic Systems – Single and Dual Zone Infra Red Thermometer in TO-39

MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39
The data on PWM / SDA must be changed when SCL is low (min 300ns after the falling edge of SCL).
The data is fetched by both MD and SDs on the rising edge of the SCL. The recommended timing for changing
data is in the middle of the period when the SCL is low.
8.4.5 Commands
RAM and EEPROM can be read both with 32x16 sizes. If the RAM is read, the data are divided by two,
due to a sign bit in RAM (for example, T_O1 - RAM address 0x07 will sweep between 0x27AD to 0x7FFF as the
object temperature rises from -70.01°C to +382.19°C). The MSB read from RAM is an error flag (active high) for
the linearized temperatures (T_O1, T_O2 and T_a). The MSB for the raw data (e.g. IR sensor1 data) is a sign bit
(sign and magnitude format). A write of 0x0000 must be done prior to writing in EEPROM in order to erase the
EEPROM cell content. Refer to EEPROM detailed description for factory calibration EEPROM locations that
need to be kept unaltered.
Opcode
000x xxxx*
001x xxxx*
1111_0000**
1111_1111
Command
RAM Access
EEPROM Access
Read Flags
Enter SLEEP mode
Table 11: SMBus commands
Note*: The xxxxx represent the 5 LSBits of the memory map address to be read / written.
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.
Flags read are:
Data[7] - EEBUSY - the previous write/erase EEPROM access is still in progress. High active.
Data[6] - Unused
Data[5] - EE_DEAD - EEPROM double error has occurred. High active.
Data[4] - INIT - POR initialization routine is still ongoing. Low active.
Data[3] - Not implemented.
Data[2...0] and Data[8...15] - All zeros.
Flag read is a diagnostic feature. The MLX90614 can be used regardless of these flags.
For details and examples for SMBus communication with the MLX90614 check the www.melexis.com
8.4.6 SMBus communication examples
SA_W = 0xB4
Command = 0x07
SA_R = 0xB5
LSByte = 0xD2
MSByte = 0x3A
PEC = 0x30
SDA
S1 0 1 1 0 1 0 WA 0 0 0 0 0 1 1 1 A S1 0 1 1 0 1 0 R A 1 1 0 1 0 0 1 0 A 0 0 1 1 1 0 1 0 A 0 0 1 1 0 0 0 0 A P
SCL
Figure 8: Read word format (SA=0x5A, read RAM=0x07, result=0x3AD2, PEC=0x30)
SA_W = 0xB4
Command = 0x22
LSByte = 0x07
MSByte = 0xC8
PEC = 0x48
SDA
S1 0 1 1 0 1 0 WA 0 0 1 0 0 0 1 0 A 0 0 0 0 0 1 1 1 A 1 1 0 0 1 0 0 0 A 0 1 0 0 1 0 0 0 A P
SCL
Figure 9: Write word format (SA=0x5A, write EEPROM=0x02, data=0xC807, PEC=0x48)
3901090614
Rev 009
Page 17 of 52
Data Sheet
June 29, 2015