STM32F303CC not working

[cbhar]

Posted on May 18, 2014 at 22:43

Hi,

I used the stm32f3 discovery board to test some code and it works fine but when I run the same code on a custom breakout I made around the stm32f303cc it runs for a while and then stops.The time it takes for the board to stop depends on the number in instructions I write. More the instructions faster does it stop working. And all i am doing is blinking LEDsCan Anyone tell me what the issue can be? Since the code runs fine on the discovery board it seems to be a hardware issue but as far as I can tell the hardware is good. The oscillator traces are good. The reset line is pulled high along with a reset control capacitor and all power pins are powered. #stm32f3-discovery #stm32f3

[cbhar]

Posted on May 20, 2014 at 19:02

I do use HSE in bypass mode by using 

 RCC->CR |= ((uint32_t) (RCC_CR_HSEON | RCC_CR_HSEBYP)); The PLL is 72Mhz via MCO. I can slow it down to 36Mhz but the micro would still get stuck. The MCO keeps running even after the micro is stuck.I dont really understand the flash wait state settings and they are set to their default value.I ll try pulling out the JTAG pins on my board for debugging but again if the code runs on the discovery board and not on mine its a hardware issue. It stops after different time intervals after reset.The capacitor is ceramic. Unpolarized.The micro jams up even if I remove all the wait statements.The current decreases around 2-4ms when it is stuck. I am not sure what to make of that.Another issue is that PB12 toggles from -720mV to 2.32V in my code so the blue led does not light up. I thought the LED was broken but as it turns out PB12 is toggling at the wrong voltage levels.The code still stops after a few white LED blinks

[Tesla DeLorean]

Posted on May 20, 2014 at 19:15

Another issue is that PB12 toggles from -720mV to 2.32V in my code so the blue led does not light up. I thought the LED was broken but as it turns out PB12 is toggling at the wrong voltage levels.

Wouldn't that suggest your grounds aren't right? How the heck can it switch to a negative voltage? Check the continuity of ALL the supply pins. Check the pin numbering vs schematicbut again if the code runs on the discovery board and not on mine its a hardware issue. An issue with your hardware, on your bench, so assume it's not wired up properly and that you will need to keep reviewing your circuit until you figure out what's broken with it.

[cbhar]

Posted on May 21, 2014 at 02:47

I guess so. I just wanted to be sure my code and schematic are correct before I start cutting traces and air wiring my PCB.

Thanks