USB2640i weird behavior
Our product is using USB2640i USB2.0 media controller. The product CPU is PPC 440Ex. There are two downstream port. One is USB for external storage, the other is micro SD card which is loaded with QNX OS 6.4. The product is in the market for a quite while.
Now, I found an issue that I think is related to USB2640i controller. When I copy a large file (ie. 800MB) from micro SD to USB, It failed to copy. I am using cp command in QNX to copy files. The failure is because the root directory has been dismounted, that is the SD card has been dismounted for some reason.
I did a bit deeper investigate. I probe the output of PIN35 - CARD_PWR which is the power provided to SD card. This pin is providing 3.3V. When the failure happens, the output of this pin is dropped. Not only this pin, even the XTAL1, XTAL2 for the crystal are also halt. Pin 47 - RBIAS is drop as well. It seems like the chip reset by itself. I thought It might be reset by the CPU. Then, I checked the Pin38 - nRESET is logic HIGH always. There is no reset signal from CPU. The 3.3 power to the chip is not dropping either.
Since the USB2640i is using default configuration. the CARD_PWR can provide 100mA sourcing current. I also monitored the current consumption of PIN35 - CARD_PWR. The DMM reads 50mA MAX, 35mA Avg. So, there is no over current at the failure moment.
If some one knows this chip well or have a clue why this failure happens. please reply to this post. I thank everyone in advance.
Thank you again.