MLX90616 Datasheet, PDF (23/36 Pages) Melexis Microelectronic Systems – Infra Red Thermometer in TO-39 for high temperature thermometer guns

MLX90616ESF-HCA
Infra Red Thermometer in TO-39
for high temperature thermometer guns
8.6 Switching Between PWM and SMBus communication
8.6.1 PWM is enabled
The diagram below illustrates the way of switching to SMBus if PWM is enabled (factory programmed POR
default for MLX90616 is SMBus, PWM disabled). Note that the SCL pin needs to be kept high in order to use
PWM.
SCL
t_REQ>1.44ms
PWM/SDA
PWM mode
Start
SMBus mode
Figure 14: Switching from PWM mode to SMBus
8.6.2 Request condition
SCL
t_{REQ >1,44ms}
Stop
SMBus Request
Figure 15: Request (switch to SMBus) condition
If PWM is enabled, the MLX90616’s SMBus Request condition is needed to disable PWM and reconfigure
PWM/SDA pin before starting SMBus communication. Once PWM is disabled, it can only be enabled by
switching the supply OFF – ON or exit from Sleep Mode. The MLX90616’s SMBus request condition requires
forcing LOW the SCL pin for period longer than the request time (t_REQ) >1,44ms. The SDA line value is
ignored in this case.
8.6.3 PWM is disabled
If PWM is disabled by means of EEPROM the PWM/SDA pin is directly used for the SMBus purposes after
POR. Request condition should not be sent in this case.
3901090616
Rev 002
Page 23 of 36
Data Sheet
August 20, 2012