Received this cheap dev board with STM32F103VET6 MCU(ARM Cortex M3) from ebay. Some code examples are bellow. Feel free to use it in your project.

STM32 and AD9850

void MM_AD9850_Init()
{
	/*
		Initialize AD9850
	  	PA0 - W_CLK
		PA1 - FQ_UD
		PA2 - DATA
		PA3 - RESET
		All output 2Mhz
	*/
	
	// enable GPIOA
	RCC->APB2ENR = RCC_APB2ENR_IOPAEN;
	
	// set pin as output, 2Mhz
	GPIOA->CRL = GPIO_CRL_MODE0_1 | GPIO_CRL_MODE1_1 | GPIO_CRL_MODE2_1 | GPIO_CRL_MODE3_1;
	
	// enable serial mode (datasheet page 12 figure 10)
	// UP
	GPIOA->BSRR = 1<<3 | 1<<0 | 1<<1;
	//DOWN
	GPIOA->BRR = 1<<3 | 1<<0 | 1<<1;
}

void MM_AD9850_SetFreq(unsigned int frequency)
{
	int n=0;
	// frequency calc from datasheet page 8 =  * /2^32
	// AD9850 has 125Mhz clock
	frequency = (frequency * 4294967296) / 125000000;  
		
	for (n=0; n<32; n++)
	{
    		// set data pin (2) to 1 or 0
		if ((frequency & 0x1) == 1)
		{
			// set data pin (2) to 1
			GPIOA->BSRR = 1<<2;
		}
		else
		{
			// set data pin (2) to 0
			GPIOA->BRR = 1<<2;
		}
		
		// W_CLK pulse, so AD9850 can shift data in register
		GPIOA->BSRR = 1<<0;
		GPIOA->BRR = 1<<0;
		
		// shift one bit...
		frequency>>=1;
  	}
	
	// all 0 for ad9850
	GPIOA->BRR = 1<<2;
	for (n=0; n<8; n++)
	{
  		// W_CLK pulse, so AD9850 can shift data in register
		GPIOA->BSRR = 1<<0;
		GPIOA->BRR = 1<<0;
	}
	
	// should be done
	GPIOA->BSRR = 1<<1;
	GPIOA->BRR = 1<<1;
}


int main(void)
{	
	...
	...
	...

	MM_AD9850_Init();
	MM_AD9850_SetFreq(10000000);

	...
	...
	...
}