Read out external device with ssp0

[dani1]

Posted on January 24, 2007 at 15:03

Read out external device with ssp0

[dani1]

Posted on May 17, 2011 at 09:35

Dear all

I would like to read out a LM95071 by SSP0. (see attachment) I connected the device on p2.4 (SC)p2.6 (MISO)p9.6(!CS) //2.7 is already used by USB_CLK and tried the following code on my Keil MCBSTR9 Evaluation Board. If I observe the pins with the scope I see no action on SC and MISO while reading. The CS(p9.6) is tied to 0 in the beginning, and always kept low. The programm is hanging in the while()-Loop on the second last line and waiting for data to come in. If I try to send data (SSP_SendData(...)) then I get a clock signal on the SC-Pin. Do you have any suggestions? Kind Regards ------------------C O D E-------------------------------- /* SCU configuration */ SCU_Configuration(); /* GPIO pins configuration */ GPIO_Configuration(); GPIO_Write(GPIO9, 0x00); //!CS = 0 /* SSP0 configuration */ SSP_DeInit(SSP0); SSP_InitStructure.SSP_FrameFormat = SSP_FrameFormat_Microwire; //SSP_InitStructure.SSP_FrameFormat = SSP_FrameFormat_Motorola; SSP_InitStructure.SSP_Mode = SSP_Mode_Master; //SSP_InitStructure.SSP_CPOL = SSP_CPOL_Low; //SSP_InitStructure.SSP_CPHA = SSP_CPHA_1Edge; SSP_InitStructure.SSP_DataSize = SSP_DataSize_16b; SSP_InitStructure.SSP_ClockRate = 5; SSP_InitStructure.SSP_ClockPrescaler = 254; SSP0->CR1 &= 0xFFFE; //switch off loopback mode SSP_Init(SSP0, &SSP_InitStructure); SSP_Cmd(SSP0, ENABLE); /* Clear SSP0 receive Fifo */ SSP0_Buffer_Rx = SSP_ReceiveData(SSP0); while(SSP_GetFlagStatus(SSP0, SSP_FLAG_RxFifoNotEmpty)==RESET); //here it is hanging SSP0_Buffer_Rx = SSP_ReceiveData(SSP0); ------------------------------------------------------

[stefano239955_stm1_stmicro]

Posted on May 17, 2011 at 09:35

Dear hazzzard,

If you configure the SPI in master mode you must send a dummy code in order to receive something from the peripheral. The SPI is a couple ''parallel to serial shift register'' The following istruction SSP0_Buffer_Rx = SSP_ReceiveData(SSP0); read the content of the shift register. try this: SPP_SendData(SSP0, 0xAA55) while(SSP_GetFlagStatus(SSP0, SSP_FLAG_RxFifoEmpty)==SET); SSP0_Buffer_Rx = SSP_ReceiveData(SSP0);

[dani1]

Posted on May 17, 2011 at 09:35

Thanks stevejamal.

I changed your code slightly since the Flag SSP_FLAG_RxFifoEmpty does not exist to: while(SSP_GetFlagStatus(SSP0, SSP_FLAG_RxFifoFull)==RESET);which should do the same (hopefully). But it still does not work. When i send, I can see the clock on the SC-Line, but there is only crap going on on the MISO Pin. Thanks anyway! haz Attachment did not work last time, hope now its working

Quote:

On 24-01-2007 at 12:43, Anonymous wrote: Dear hazzzard, If you configure the SPI in master mode you must send a dummy code in order to receive something from the peripheral. The SPI is a couple ''parallel to serial shift register'' The following istruction SSP0_Buffer_Rx = SSP_ReceiveData(SSP0); read the content of the shift register. try this: SPP_SendData(SSP0, 0xAA55) while(SSP_GetFlagStatus(SSP0, SSP_FLAG_RxFifoEmpty)==SET); SSP0_Buffer_Rx = SSP_ReceiveData(SSP0);