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Altera_Forum's avatar
Altera_Forum
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16 years ago

how can I use sdram

hello,everybody: I want to use off chip sdram as a data menmory. First I store some data in sdram. Second I want process these data in nios II processor using c language. But how ca...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

you should read the application note an517, that you can download from http://www.altera.com/literature/an/an517.pdf

with IORD and IOWR you should be able to write and read to/from the SDRAM... here you have a simple code as example. 

void readFromSDRAM(int offset){
    unsigned int DDR_read_OFFSET_ADDRESS = offset;
    unsigned int read_data;
    if ((DDR_read_OFFSET_ADDRESS<0) || (DDR_read_OFFSET_ADDRESS>=(ALTMEMDDR_SPAN/4))){
        printf("error");
    }else{
        read_data=IORD(ALTMEMDDR_BASE,DDR_read_OFFSET_ADDRESS);
        printf("Read %08x from address %08x \n",read_data,(ALTMEMDDR_BASE+DDR_read_OFFSET_ADDRESS));
    }
}
void writeToSDRAM(int data, int offset){
    unsigned int DDR_write_OFFSET_ADDRESS = offset;
    if((DDR_write_OFFSET_ADDRESS<0)||(DDR_write_OFFSET_ADDRESS>=(ALTMEMDDR_SPAN/4))){
        printf("error");
        return;
    }
    IOWR(ALTMEMDDR_BASE,DDR_write_OFFSET_ADDRESS,data);
    if (IORD(ALTMEMDDR_BASE,DDR_write_OFFSET_ADDRESS)==data){
        printf("Data: %08x is correctly written to memory offset: %08x \n",data,DDR_write_OFFSET_ADDRESS);
    }else{
        printf("error");
    }
}