SPI trans data wrong

weilsng li

Other Parts Discussed in Thread: CC3200

hello：

I am using cc3200 spi as slave mode.Transfer data num is 8.I find if the master send not enough 8 clk to read data,it will affect the follow-up data.

Such as slave spi send 0x55 and 0xaa.The master spi send 4 clk first ,Then it send 8 CLK,it will recive 0x5a.

How can i avoid this.How can i clear the shift register.I try to reset spi,but it is not fine.

over 10 years ago

0 Praveen Kumar N over 10 years ago

TI__Expert 6700 points

Hi weilsng,

Can you please post more details about your requirement. Is it one of you requirement that you will send first 4 clocks then 8 clocks?

How did you reset the SPI (which API) ?

Thanks and Regards,

Praveen

0 Glenn Vassallo over 10 years ago

Guru 21435 points

As per the SPI example provided with the SDK. Have you included the following code to clean up receive register after you have pushed out data on SPI using MAP_SPIDataPut?

//
// Clean up the receive register into a dummy
// variable
//
MAP_SPIDataGet(GSPI_BASE,&ulDummy);

Glenn.

0 weilsng li over 10 years ago in reply to Praveen Kumar N

Prodigy 235 points

hi Praveen，

This is not my requirement .For example ,if the master spi equipment problems,it only send 4 clk,then it restarts.But the cc3200 with slave spi does not know this.From now on,the master spi send 8 clk ,but the data is wrong.Can i avoid this .

0 Praveen Kumar N over 10 years ago in reply to weilsng li

TI__Expert 6700 points

Hi weilsng,

You can flush the internal SPI FIFO by disabling and re-enabling the channel. Use MAP_SPIEnable() and MAP_SPIDisable() to enable/disable the SPI channel.

Thanks and Regards,

Praveen

0 weilsng li over 10 years ago in reply to Praveen Kumar N

Prodigy 235 points

Hi Praveen ,

Is there a flag showing this phenomenon .I am not sure when this phenomenon will happen.

0 Praveen Kumar N over 10 years ago in reply to weilsng li

TI__Expert 6700 points

Hi Weilsng,

No, slave can't know if it has got required number of clocks or not from the master, but you can implement a software protocol to sync master and salve intermittently. Like master can start a communication with a SYNC Pattern, may be a header followed by data.

Thanks and Regards,

Praveen

0 weilsng li over 10 years ago in reply to Praveen Kumar N

Prodigy 235 points

Thanks Praveen.

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SPI trans data wrong