NXP Semiconductors QorIQ LX2160A - 2.17 LEDs

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THERM_WRN_B
DUT
I2C bus
THERM_FLT_B
VDD
SD_SVDD
SD_OVDD
GVDD
.....
CPLD
Device power
Indicator
1U
PSU
Shut down
.....
Thermal sensor 1
(SA56004ED)
TEMP_DIODE1_P
TEMP_DIODE1_N
TD1_ANODE
TD1_CATHODE
TD2_ANODE
TD2_CATHODE
Thermal sensor 2
(SA56004FD)
TEMP_DIODE2_P
TEMP_DIODE2_N
Figure 2-26. Thermal management scheme
Thermal monitoring happens with no programming involved. However, if the thermal
limit, by default set as 85 °C, is higher than desired, it will need to be re-programmed. To
change the thermal trip point, issue the I2C writes listed in the table below.
Table 2-17. Thermal monitor configuration
I2C write Description
0x77 0x0B 0x0B Program primary I2C bus multiplexer (PCA9547PW) to get access to
I2C1_CH3 (I2C sub-channel for SA56004ED/SA56004FD)
0x4C 0x19 <TLIMIT> (thermal monitor 1)
0x4D 0x19 <TLIMIT> (thermal monitor 2)
Program the thermal limit of SA56004ED/SA56004FD external
measurement (the processor). <TLIMIT> can be any user-defined
value, for example, decimal 50.
NOTE
The SW_BYPASS_B switch (SW4[1]) disables thermal
monitoring. This may be necessary if operating the board
without a processor installed, as an open thermal diode
connection will measure as 127 °C.
LEDs
QorIQ LX2160A Reference Design Board Reference Manual, Rev. 0, 09/2018
52 NXP Semiconductors