Other Parts Discussed in Thread: DP83848C
In a product I designed, the LAN drive circuit(MII mode) is composed of STM32F107VGT6 and DP83848CVV. The function is very normal. There are no problems with factory testing. After using it in the hands of customers for half a month, the product does not work one after another. Not even the computer. Analyzing the returned products, it was found that the RESET foot of the DP83848C was short-circuited to the ground, and the STM32F107 could not be started. The RESET foot of DP83848 is directly connected to the RESET PIN of STM32F107 and then grounded by a 100NF capacitor. Disconnect RESETTSTM32F107 RESET PIN with DP83848C, STM32F107 works fine. The GPIO impedance of DP83848 is roughly measured by a multimeter. Only the RESET PIN impedance is as low as a few tens of ohms, and the other GPIO impedance is not abnormal. Power the normal DP83848, artificially pulling the low RESET level, other GPIO levels are the same as the RESET PIN impedance of only a few tens of ohms of DP83848. At present, it seems that DP83848 is only damaged by RESET PIN, but somehow it will be damaged, and instead of directly linking STM32F107 RESET PIN, it is normal? If the RESET foot of DP83848 is suspended, is it possible to solve this problem(assuming that it is external damage, is it possible that it is damaged from inside the chip? )? Please, thank you!
