MLX90314
Programmable Sensor Interface
Alarm Option
IO1 & IO2
This option allows controlling the low and high limits of
the output (See Figure 5.). The output level is set
when the output tries to exceed the programmed
limits. Five bytes are reserved for this option. The first
byte is the low trigger limit and the second the low
output. The third and fourth bytes are used for the high
limit and the output. The fifth byte is the alarm control,
used to select the alarm input. The different levels are
programmed as eight bit numbers. These correspond
to the 8 upper bits of the 10 bit signal measurement.
When the alarm mode is not used, all of the data is 0.
The control code is coded as shown in Table 7. The
six possible signals are listed below and are encoded
on the 4 MSB’s of byte 31 of the EEPROM.
IO1 and IO2 are used in the alarm and level steering
modes. For custom firmware, they can be used for a
digital input, an analog input, or a digital output.
Figure 6.
Alarm & Steering
Source Points
OFC
FLT
VDD1 FET VDD GND
Power Supply
Regulation
IAO
GNO
VBP
VBN
VM
Offset
Gain
VMO
Table 7. Alarm Source Bit Definition
Selected input
MUX Value
TPO
CM
CMO
TPO
IAO
GNO
VMO
IO1
0010
0110
0000
0011
0100
0101
CMN
Temp
Sense
& Amp
TMP
ADC
&
DAC
Microcontroller
Core, Memory,
EEPROM
IO2
TSTB
Reset,Test,&
Oscillator
IO1
IO2
Bidirectional
I/O
UART
COMS
Figure 5.
Alarm Function
OUTPUT
MLX90314
Figure 7. Level Steering
Function
High
Output
MLX90314
IO1, IO2
1 -1
1 - 0
Low
Output
0 - 1
0 - 0
(I02,I01)
Low
High
Trigger
Trigger
Level 1
Level 2
Level 3
Input Signal
MLX902xx Name of Sensor Rev Y.X 22/Aug/98
3901090314
Page 13
Page 13
Nov/04
Rev 007
MELEXIS [ Melexis Microelectronic Systems ]
