I have a project that is dependent on the GHI Cerbuino Bee board. Since this board is no longer available I decided to put the STM32F405 on my own PCB. I copied most of the schematic for the Cerbuino in terms of the pins I thought were required to place the device into the ST Micro DFU mode.
On power up of my new board with BOOT0 high and BOOT1 low. and connected via USB, my computer does not see any USB devices attached. Not even an unrecognized device.
So I suspected it must be the crystal but I used one with the same specifications as the on on the cerbuino board. I also used the same decoupling caps. I do notice the crystal pins have a voltage spike when releasing reset while holdiing down the LDR, but the crystal never starts oscillating.
So then I questioned whether a virgin STM32F405 actually has a bootloader in it.So I looked through the STM specs and found the bootloader is also supposed to respond on the serial port. I connected a serial port and continuously sent 0x7F while reseting with boot0 high and it actually responded.
I then found a STM serial firmware updater and used this to upload tiny_booter into this device through the serial port. It worked and was very surprised that my PC immediately detected the cerb-familty device on the USB port.
Now when I looked at the crystal it is oscillating correctly at 12mhz.
So, a long winded preamble to my question, why would the ST DFU device not show up in device manager when I enable the built in bootlader. Is there something special you need configured in terms of I/O pins?
When I hold down LDR and release reset on my Cerbuino bee boards, my PC immediately detects a device in DFU mode so I know my device drivers are installed correctly.
Could it still be an issue with crystal startup times? Would the GHI firmware be more tolerant to PLL stabilization times than the ST bootloader?
I have tried multiple USB ports and multiple computers. Doing the same process with a Cerbuino Bee brings up the DFU device immediately so I doubt its the device drivers.
Like I mentioned in my original post, the 12Mhz Oscillator never starts and from what I have ready you can not get any USB activity without this external oscillator running. So I still feel is something to do with the crystal. Its just odd that is runs fine with the GHI code loaded.
The Uart does work, that is how I installed the GHI firmware on the device. Its just very cubersome for me to do it this way. I would really like to get the DFU mode working.
I just built 4 more boards. DFU mode does not work on any of them.
I used STs RS232 Flash loader to installed Tiny Booter 188.8.131.52. This worked on all the boards
Used FEZConfig to load the GHI firmware on all boards.
Loaded my application and can debug through VS on all boards
All boards run fine in application mode, Crystal runs as expected.
I have the same issue of santhosh, I bought some G80’s from Mouser the last 30th of august, All the units seem to be blank
I have the same issue of santhosh, I bought some G80’s from Mouser the last 30th of august, All the units seem to be blank, there is no bootloader pre loaded. Can you tell me what can I do? Can you redirect me to the response you are talking about? Thanks