t Number: DP83848I
Dear Sir, please answer
I use DP83848I with external oscillator 25 Mhz. We have three boards and all boards start badly at a negative temperatures. DP83848I's are starting to work with a delay of 15 ...80 s at a negative temperature. At a temperature of minus 7 C, the delay is 15 seconds after power on. At a temperature of minus 40 ° C, the delay is 80 s after power on. I checked the external oscillator G2 with an oscilloscope - it starts working immediately after power on (at a negative temperature). We use PIC32MZ processor and we found out, that it starts working immediately after power on (at a negative temperature), that is without delay - it is absolutely certain.
The DP83848I is labeled " DP83848VV
VBI".
In accordance with the our program, the processor PIC32MZ must first initialize the exchange with DP83848I, and then PIC32MZ starts to perform further actions.
At a positive temperature, after turning on the power, the yellow LED flashes once on the module TRJ1609 immediately after turning on the power (the LED is connected to the pin 28 of the DP83848I). At a negative temperature, this LED flashes once with a DELAY of 15....80 s (depending on temperature). As soon as this LED blinks once, the board starts working. So we believe, that the reason for the delay - in the DP83848I. The impression, that DP83848I starts to work, when something "warms up" inside. When DP83848I starts up, Ethernet port works good.
What could be wrong with DP83848I at a negative temperature? Maybe, this is due to an unsuccessful arrangement of capacitors C48, C50, C51, C52?
TIA
Sincerely
Vladimir Naumenkov
www.agat.by
