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Problem with ADC, GPIO and DMA

Question asked by shrestha.durgesh on Oct 20, 2011
Among all of the functions implemented in my project, i have configured PC4 as an input for ADC conversion and implemented the DMA. I had the application successfully operated in stm32primer2 but now i am working with olimex board stm32h103 that contains stm32f103rbt6 microcontroller.
Now the ADC is not working and the port at PC4 without any input has a square wave of 1kHz and the falling edge as somehow transient. The value of related registers are:
GPIOC, Mode 4: Input MOde (reset state)
CNF4: Analog input mode or General Purpose output push-pull.
Port input Data Register (IDR): 0xf7ee

DMA Channel 1 peripheral address register (DMA_CPAR1): 0x4001244C
(DMA_CMAR1): 0x20000b7c
DMA Channel 1 configuration register (DMA_CCR1): 0x2583
DMA Channel 1 no. of data register (DMA_CNDTR1): the value is changing

ADC control register 1 (ADC_CR1): 0x100
ADC Control Register 2(ADC_CR2): 0x1e090
ADC watchdog high threshold register (ADC_HTR): 0xfff
ADC regular data register (ADC_CR): moving, data changing.

The program i use is ride7 and now i am not able to take the input analog voltage. I would be happy if anyone would suggest something specially i did not find the reason why the pin chosen as input for ADC conversion is giving a square wave of around 1.5V and 1kHz.