Stm32f411 SPI2 output error, pb15 has no pulse debugging record [finally, pb15 and pb14 were found to be short circuited]

Debugging last night TFT when , Due to hardware problems TFT Of SDA and SCL Interface is used in SPI2 Of PB15（SPI_MOSI） And PB13（SPI2_SCK） On .
There should be no problem with the logic in the program , And also in SPI1 The port has been verified , The normal operation , But received SPI2 There is no output on ,
Thought it was hardware SPI Why , Replaced by software SPI,

void LCD_SPIx_WriteByte(u8 data)
{
       
// HAL_SPI_Transmit(&LCD_SPI_CH,&data,1,0xffff);
	
	unsigned char i=0;
    for ( i = 8; i > 0; i --)
    {
    
        LCD_SCL_CLR;
        if ( data & 0x80)   
            LCD_SDA_SET; // Output data 
        else 
            LCD_SDA_CLR;    
        LCD_SCL_SET;
        data <<= 1; 
    }
}

however TFT It still doesn't show .
Last one blog:STM32F4-TFT-SPI Commissioning record of sequential logic analyzer
The normal timing has been captured by the logic analyzer , Only change to PB15 and PB13 There is no output on .
The logic analyzer found ：

SCL–PB13 The pin sends pulses normally , however SDA–PB15 The hardware is always high , So the problem may be PB15 On ,
And now it's software SPI, Do not rule out PB15 In hardware SPI It is also constant high in mode , Check it out .
Change to hardware SPI：

Output is still problematic , Now we can locate the root cause should be SPI_MOSI That is to say PB15 There is a problem .

Check the hardware , See if there is a short circuit
Find out PB15 And PB14 A short circuit ！！！！
Cheating ....
Change into another chip with tears
Then test

The timing is basically wrong , No wonder it can't be displayed ...
Switch to software SPI try , See if there is something wrong with the hardware ;

It's still not right ,TFT It doesn't show
Change SDA Pin to PB2：

This meeting seems to be right , however TFT No display , The inspection found that DC The pin is connected incorrectly , In turn, , According to the normal
Then change SDA To PB15：
According to the normal ！！！！
Poor migrant workers in Shenzhen , Line up to do nucleic acid ....

-------------------------------------- Split line --------------------------------------------

Make nucleic acid ,
Change to hardware SPI Well ？

The timing looks wrong , But normal display ... Suddenly I remember

This is awkward ... The sampling rate is only twice as high ... Moreover, it is already the highest sampling rate of the logic analyzer ！！！.
But I can only adjust the hardware SPI Baud rate

Finally, it is normal ！！！！
Admire myself ！！！

However, I think of another one before bug:
【STM32-USB-MSC Ask for help 】STM32F411CEU6 (WeAct)+w25q64+USB-MSC Flash use SPI2 The readout capacity is only 520KB

This is also the same development board ,,,, Should not ？？ Cold behind .. Test it tomorrow ..