for my diploma thesis, i created a complex custom board using ALFAT2 to store data on a SD card. I also implemented the suggested FUSB2805 for High-Speed acces as a mass storage device when plugging into a USB port. I tested all my software routines with your OEM evalution board and everything worked fine.
Now when I try to open ALFAT in SPI mode, I get no respond (BannerString) back from it. Since I have a custom board the possible error sources can be a lot. For example since ALFAt is the STM32F205RBT6 I used the respective datasheet for crystal selection.
I use a ABS07-LR-32.768KHZ-6-1-T from Abracon llc for the 32.768kHz crystal with two 14pF load capacitors according to the datasheet and a 7A-12.000MAAE-T from TXC Corporation for the 12MHz crystal with two 2pF load capacitors according to the datasheet.
Do you know how I should start to search for the error? Power is ok, and i also implemented the LED on U1_CONNECT to check if there is a USB connection, and it sometimes did work. Is there a possibility to check for the CLKs? I cannot measure at the crystals so is there another pinout?
Here’s a part of my schematic with the relevant circuits for ALFAT: