Posted on February 24, 2016 at 16:50
It looks like the ''ZG'' vesion is faster than the other, but the RCC registers are the same. What else worries me is the first line ( D+). It differs from working device's D+, but I dont know why. Also the USB registers are the same, besides the amount of frames sent. I don't know what may be wrong. The paths on the pcb are just a bit longer, and that's the only physical difference that I'm able to spot. Hope You can help me! Greetongs,Peter
Hello!
I have a strange problem with the mass storage usb on stm32407ZGt6. Why is it odd ? That's because the same code works on stm32f407ZEt6 just fine. I thought that these cpu's differ only in the amount of flash memory, but clearly there is something else. I have checked the following things: -CPU clocks ( the registers are the same in both cpu's) -The voltage ( I added extra capacitors)-the crystal - 16 mhz working well -electrical connections -D+ D- are not swapped or anything like this, the 1,5 k resistor on D+ does not make it work.-the code is exactly the sameBut still on the device with 407zGt6 the PC shows a sign ''unknown device'', and on 407zEt6 works as it should. So I decided to sniff the signals with the logic analyser. this is what I've noticed: (3 pics different zoom ( top 2 signals are from the not working one ) :It looks like the ''ZG'' vesion is faster than the other, but the RCC registers are the same. What else worries me is the first line ( D+). It differs from working device's D+, but I dont know why. Also the USB registers are the same, besides the amount of frames sent. I don't know what may be wrong. The paths on the pcb are just a bit longer, and that's the only physical difference that I'm able to spot. Hope You can help me! Greetongs,Peter
