Continuous access time interval of K10 FlexBus is too long，WHY?

[yangzeyong]

I use k10 to access sram. port size is 16bit. Data write and read is correct

BUT:  interval time between two access is too Long. so the performace of flexbus is very low

WHY??

Acess SRAM 16 times takes 16us，See the attachment picture

Thanks...

[Hui_Ma]

Hi,

Could you please post the code about write data to external SRAM?

Have a great day,
Mike

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[yangzeyong]

Hi,Hui_Ma:

     Code is below：

#define SRAM_START_ADDRESS   (*(volatile unsigned char*)(0x60000000))
unsigned short LoadWord(unsigned int offset)
{
        return (*(volatile unsigned short*)(&SRAM_START_ADDRESS + offset));
}

void StoreWord(unsigned int offset,unsigned short data)
{
        *(volatile unsigned short*)(&SRAM_START_ADDRESS + offset) = data;
}

void SramWriteBuffer(unsigned short *pBuf,unsigned int addr,unsigned int length)
{
     int s,t;
     if((addr % 2 >0) || (length % 2 >0))
    {
           return;
     }

      s=length/2;
    for(t=0;t<s;t++)
    {
        StoreWord(addr+t*2, *(pBuf+t*2));
    }
 }

///////////////  TestSram ： write sram 16 times

void TestSram(void)
{
     unsigned short wbuf[16];
     unsigned int t;
     for(t=0;t<16;t++)
     {
            wbuf[t]=0x1234+t;
      }
     SramWriteBuffer(wbuf,0x0,16*2);
}

Thank you！

[Hui_Ma]

Hi,

Could you tried to use below code to do 16 times SRAM write (write to the same address 16 times)? How about the result?

void TestSram(void)
{
     unsigned int t;

     for(t=0;t<16;t++)
     {

         *(volatile unsigned short*)(&SRAM_START_ADDRESS ) = 0x1234;

    }

}

[yangzeyong]

Hi,Hui_Ma:

    The timing  writing to the same address 16 times looks normal，takes about 4us. Great Job！

    What's the problew of origin code?  Thank you!

[Hui_Ma · Accepted solution]

Hi,

Please check the original code disassembly code.

You can set the compiler optimize level to enhance code execute speed.

Wish it helps.

Have a great day,
Mike

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