Hiroaki Ogino

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8 years, 5 months ago.

HOW to use on board DRAM

I use DISCO-F746NG board and I want to extend memory by using on-board DRAM.

There is API of this board "BSP_DISCO_F746NG" and it contains "stm32746g_discovery_sdram.h" and ".c" file. In C file.

I try under code,but I cannot Read and Write DRAM.

#include "mbed.h"
#include "stm32746g_discovery_sdram.h"
Serial pc(SERIAL_TX, SERIAL_RX);//9600bps
void main(){
//initialize and check init status.
//I got a "SDRAM init OK" message.
    if(status == SDRAM_OK) {
        pc.printf("SDRAM init OK\n");
    } else if(status == SDRAM_ERROR) {
        pc.printf("SDRAM init ERR\n");
    } else if (status == 0x5) {
        pc.printf("SDRAM init never done\n");
    } else {}

    //mem check:To assign data to all memory and check it.

    uint32_t start_addr=    0xC0000000;//In stm32746g_discovery_sdram.h, it tell me Device address.
    uint32_t mask =         0x0fffffff;
    uint32_t data =         0x10000000;
    uint32_t read_data =    0x10000000;
    uint32_t point_of_data =0x0000000f;
    uint32_t i;

//mem check write
    for(i=0; i<point_of_data; i++) {
        BSP_SDRAM_WriteData_DMA(start_addr+i,&data,0x1);
        pc.printf("write: addr is %x, data is %x\n",start_addr+i,data);
        data ++;
    }

//mem check read
    for(i=0; i<point_of_data; i++) {
        BSP_SDRAM_ReadData(start_addr+i,&read_data,0x1);
                    pc.printf("addr is %x, data is %x\n",start_addr+i,read_data);
        if(data&mask == i) { //data masked off upper 4bit is equal data.
            //data is OK
        } else {
            pc.printf("mem check is error\n");
        };
}

Do I mistake using SDRAM? Please teach me some hints... thanks.

Referrence (TS_DISCO_F746 lib) https://developer.mbed.org/teams/ST/code/TS_DISCO_F746NG/

(BSP_DISCO_F746NG lib) https://developer.mbed.org/teams/ST/code/BSP_DISCO_F746NG/

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