MLX90616 Datasheet, PDF (17/36 Pages) Melexis Microelectronic Systems – Infra Red Thermometer in TO-39 for high temperature thermometer guns

8.4.5 Bit transfer
SCL
MLX90616ESF-HCA
Infra Red Thermometer in TO-39
for high temperature thermometer guns
Sampling ^Changing
data
data
PWM/SDA
Figure 9: Bit transfer on SMBus
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.
8.4.6 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, TOBJ - RAM address 0x07h will sweep between 0x27ADh to 0xFFFF as the
object temperature rises from -70.01°C to +1037.55°C). 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 9: SMBus commands
Note*: The xxxxx represent the 5 LSBits of the memory map address to be read/written.
Note**: Behaves like read command. The MLX90616 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.
Flags read is a diagnostic feature. The MLX90616 can be used regardless of these flags.
For details and examples for SMBus communication with the MLX90616 check the www.melexis.com
3901090616
Rev 002
Page 17 of 36
Data Sheet
August 20, 2012