AM62A7-Q1: How to RD (Read) DQ Calibration in Nanya DRAM?

Hi Xue,

There are a few registers which allow the user to read/write MR registers in the memory.  Here are some example GEL functions which should be easily adapted to C code.  The functions will only work if the DDR controller/PHY are properly initialized and trained.

Wait()
{
unsigned int i;
for(i=0;i<10000;i++);
}

Check_and_Ack_MRW()
{
while((HW_RD_REG32(CTL_BASE + DDRSS_CTL_351__SFR_OFFS) & 0x8) == 0x0)
Wait();
HW_WR_REG32(CTL_BASE + DDRSS_CTL_359__SFR_OFFS, 0x8); //ack the status mode bit
Wait();
}

Check_and_Ack_MRR()
{
while((HW_RD_REG32(CTL_BASE + DDRSS_CTL_351__SFR_OFFS) & 0x4) == 0x0)
Wait();
HW_WR_REG32(CTL_BASE + DDRSS_CTL_359__SFR_OFFS, 0x4); //ack the status mode bit
Wait();
}

hotmenu MR_Write(unsigned int mr_addr,unsigned int cs, unsigned int data)
{
HW_WR_REG32(CTL_BASE + DDRSS_CTL_190__SFR_OFFS,((1UL << 23) | (cs << 8) | mr_addr));
Wait();
HW_WR_REG32(CTL_BASE + DDRSS_CTL_225__SFR_OFFS, data );
//trigger write
Wait();
HW_WR_REG32(CTL_BASE + DDRSS_CTL_190__SFR_OFFS, ((1UL << 25) | (1UL << 23) | (cs << 8) | mr_addr)); //set bit 25 to write
Wait();
Check_and_Ack_MRW();
GEL_TextOut("Writing %x to MR%d\n",,,,,data,mr_addr);

}

hotmenu MR_Read(unsigned int mr_addr,unsigned int cs)
{
HW_WR_REG32(CTL_BASE + DDRSS_CTL_190__SFR_OFFS, ((cs << 8) | mr_addr) << 8 ); //CS0 MR0
HW_WR_REG32(CTL_BASE + DDRSS_CTL_190__SFR_OFFS, ((1UL<<16) | (cs << 8) | mr_addr) << 8 ); //trigger read
Check_and_Ack_MRR();
return(HW_RD_REG32(CTL_BASE + DDRSS_CTL_192__SFR_OFFS));

}

Regards,

James