AnsweredAssumed Answered

No signal on mco1

Question asked by Kauppi.Teijo on Dec 13, 2012
Latest reply on Dec 14, 2012 by Kauppi.Teijo
hello, 
 
I'm using stm32f207(LQFP64) mcu in custom made hw. Compilers are gnu 
arm-eabi-gcc and arm-eabi-gdb for debugging. 
 
main fuctions for mcu are: 
- output 27mhz clock MCO1(PA8) 
- listen interrupts at EXTI15_10_IRQ(PB15). This is active low 
- Mcu uses internal RC oscilator and is configured to 108MHz clock 
 
This sw is tested in the previous hw and it's working fine. But now i'm 
trying to test newer version of hw and I run into very strange problems. 
 
1. there is no clock in the MCO1 pin. 
2. when I debug the code, ext irq occurs even if there is no pulses in the 
irq line(I've checked it with a scope). (The code it goes to Reset_Handler). 
 
So i made test code that tricles test pin (GPIOx) and feeds clock to MCO 
pin. Test pin changes state fine, but I don't see the clock signal at the (PA8) 
MCO output. I tested this code to anoter hw(other project same mcu(LQFP100)) 
and there are correct signal from MCO pin. 

any help will be appreciated. br, Teijo

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