【兆易GD32H759I-EVAL】--7.SDRAM读写

dirty

【兆易GD32H759I-EVAL】--7.SDRAM读写 [复制链接]

本帖最后由 dirty 于 2024-5-22 21:46 编辑

本篇讲述对外部SDRAM的读写。

一.硬件原理

开发板板载一颗MT48LC16M16A2 SDRAM 芯片，大小为 32MB，具有较大的存储空间。SDRAM原理图及引脚定义如下:

图1:SDRAM原理图

图2:SDRAM引脚定义

二.代码准备

1.宏定义读写数据大小、读写地址

/* SDRAM */
#define BUFFER_SIZE                ((uint32_t)0x0400)
#define WRITE_READ_ADDR            ((uint32_t)0x0000)

2.引脚初始化，包括使能EXMC时钟及选择SDRAM。

    /* enable EXMC clock */
    rcu_periph_clock_enable(RCU_EXMC);
    rcu_periph_clock_enable(RCU_GPIOA);
    rcu_periph_clock_enable(RCU_GPIOC);
    rcu_periph_clock_enable(RCU_GPIOD);
    rcu_periph_clock_enable(RCU_GPIOE);
    rcu_periph_clock_enable(RCU_GPIOF);
    rcu_periph_clock_enable(RCU_GPIOG);
    rcu_periph_clock_enable(RCU_GPIOH);

    /* common GPIO configuration */
    /* SDNE0(PC2),SDCKE0(PC3) pin configuration */
    gpio_af_set(GPIOC, GPIO_AF_12, GPIO_PIN_2 | GPIO_PIN_3);
    gpio_mode_set(GPIOC, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN_2 | GPIO_PIN_3);
    gpio_output_options_set(GPIOC, GPIO_OTYPE_PP, GPIO_OSPEED_85MHZ, GPIO_PIN_2 | GPIO_PIN_3);

    /* D12(PC0) pin configuration */
    gpio_af_set(GPIOC, GPIO_AF_1, GPIO_PIN_0);
    gpio_mode_set(GPIOC, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN_0);
    gpio_output_options_set(GPIOC, GPIO_OTYPE_PP, GPIO_OSPEED_85MHZ, GPIO_PIN_0);

    /* D2(PD0),D3(PD1),D13(PD8),D14(PD9),D15(PD10),D0(PD14),D1(PD15) pin configuration */
    gpio_af_set(GPIOD, GPIO_AF_12, GPIO_PIN_0 | GPIO_PIN_1 | GPIO_PIN_8 | GPIO_PIN_9 |
                GPIO_PIN_10 | GPIO_PIN_14 | GPIO_PIN_15);
    gpio_mode_set(GPIOD, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN_0  | GPIO_PIN_1  | GPIO_PIN_8 | GPIO_PIN_9 |
                  GPIO_PIN_10 | GPIO_PIN_14 | GPIO_PIN_15);
    gpio_output_options_set(GPIOD, GPIO_OTYPE_PP, GPIO_OSPEED_85MHZ, GPIO_PIN_0  | GPIO_PIN_1  | GPIO_PIN_8 | GPIO_PIN_9 |
                            GPIO_PIN_10 | GPIO_PIN_14 | GPIO_PIN_15);

    /* NBL0(PE0),NBL1(PE1),D4(PE7),D5(PE8),D6(PE9),D7(PE10),D8(PE11),D9(PE12),D10(PE13),D11(PE14) pin configuration */
    gpio_af_set(GPIOE, GPIO_AF_12, GPIO_PIN_0  | GPIO_PIN_1  | GPIO_PIN_7  | GPIO_PIN_8 |
                GPIO_PIN_9  | GPIO_PIN_10 | GPIO_PIN_11 | GPIO_PIN_12 | GPIO_PIN_13 |
                GPIO_PIN_14);
    gpio_mode_set(GPIOE, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN_0  | GPIO_PIN_1  | GPIO_PIN_7  | GPIO_PIN_8 |
                  GPIO_PIN_9  | GPIO_PIN_10 | GPIO_PIN_11 | GPIO_PIN_12 | GPIO_PIN_13 |
                  GPIO_PIN_14);
    gpio_output_options_set(GPIOE, GPIO_OTYPE_PP, GPIO_OSPEED_85MHZ, GPIO_PIN_0  | GPIO_PIN_1  | GPIO_PIN_7  | GPIO_PIN_8 |
                            GPIO_PIN_9  | GPIO_PIN_10 | GPIO_PIN_11 | GPIO_PIN_12 | GPIO_PIN_13 |
                            GPIO_PIN_14);

    /* A0(PF0),A1(PF1),A2(PF2),A3(PF3),A4(PF4),A5(PF5),NRAS(PF11),A6(PF12),A7(PF13),A8(PF14),A9(PF15) pin configuration */
    gpio_af_set(GPIOF, GPIO_AF_12, GPIO_PIN_0  | GPIO_PIN_1  | GPIO_PIN_2  | GPIO_PIN_3  |
                GPIO_PIN_4  | GPIO_PIN_5  | GPIO_PIN_11 | GPIO_PIN_12 |
                GPIO_PIN_13 | GPIO_PIN_14 | GPIO_PIN_15);
    gpio_mode_set(GPIOF, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN_0  | GPIO_PIN_1  | GPIO_PIN_2  | GPIO_PIN_3  |
                  GPIO_PIN_4  | GPIO_PIN_5  | GPIO_PIN_11 | GPIO_PIN_12 |
                  GPIO_PIN_13 | GPIO_PIN_14 | GPIO_PIN_15);
    gpio_output_options_set(GPIOF, GPIO_OTYPE_PP, GPIO_OSPEED_85MHZ, GPIO_PIN_0  | GPIO_PIN_1  | GPIO_PIN_2  | GPIO_PIN_3  |
                            GPIO_PIN_4  | GPIO_PIN_5  | GPIO_PIN_11 | GPIO_PIN_12 |
                            GPIO_PIN_13 | GPIO_PIN_14 | GPIO_PIN_15);

    /* A10(PG0),A11(PG1),A12(PG2),BA0/A14(PG4),BA1/A15(PG5),SDCLK(PG8),NCAS(PG15) pin configuration */
    gpio_af_set(GPIOG, GPIO_AF_12, GPIO_PIN_0 | GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_4 |
                GPIO_PIN_5 | GPIO_PIN_8 | GPIO_PIN_15);
    gpio_mode_set(GPIOG, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN_0 | GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_4 |
                  GPIO_PIN_5 | GPIO_PIN_8 | GPIO_PIN_15);
    gpio_output_options_set(GPIOG, GPIO_OTYPE_PP, GPIO_OSPEED_85MHZ, GPIO_PIN_0 | GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_4 |
                            GPIO_PIN_5 | GPIO_PIN_8 | GPIO_PIN_15);
    /* SDNWE(PH5) pin configuration */
    gpio_af_set(GPIOH, GPIO_AF_12, GPIO_PIN_5);
    gpio_mode_set(GPIOH, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN_5);
    gpio_output_options_set(GPIOH, GPIO_OTYPE_PP, GPIO_OSPEED_85MHZ, GPIO_PIN_5);

    /* specify which SDRAM to read and write */
    if(EXMC_SDRAM_DEVICE0 == sdram_device) {
        bank_select = EXMC_SDRAM_DEVICE0_SELECT;
    } else {
        bank_select = EXMC_SDRAM_DEVICE1_SELECT;
    }

3.配置SDRAM时序寄存器

 /* step 1 : configure SDRAM timing registers --------------------------------*/
    /* LMRD: 2 clock cycles */
    sdram_timing_init_struct.load_mode_register_delay = 2;
    /* XSRD: min = 67ns */
    sdram_timing_init_struct.exit_selfrefresh_delay = 12;
    /* RASD: min=42ns , max=120k (ns) */
    sdram_timing_init_struct.row_address_select_delay = 8;
    /* ARFD: min=60ns */
    sdram_timing_init_struct.auto_refresh_delay = 11;
    /* WRD:  min=1 Clock cycles +6ns */
    sdram_timing_init_struct.write_recovery_delay = 2;
    /* RPD:  min=18ns */
    sdram_timing_init_struct.row_precharge_delay = 4;
    /* RCD:  min=18ns */
    sdram_timing_init_struct.row_to_column_delay = 4;

4.配置SDRAM控制寄存器

/* step 2 : configure SDRAM control registers ---------------------------------*/
    sdram_init_struct.sdram_device = sdram_device;
    sdram_init_struct.column_address_width = EXMC_SDRAM_COW_ADDRESS_9;
    sdram_init_struct.row_address_width = EXMC_SDRAM_ROW_ADDRESS_13;
    sdram_init_struct.data_width = EXMC_SDRAM_DATABUS_WIDTH_16B;
    sdram_init_struct.internal_bank_number = EXMC_SDRAM_4_INTER_BANK;
    sdram_init_struct.cas_latency = EXMC_CAS_LATENCY_3_SDCLK;
    sdram_init_struct.write_protection = DISABLE;
    sdram_init_struct.sdclock_config = EXMC_SDCLK_PERIODS_3_CK_EXMC;
    sdram_init_struct.burst_read_switch = ENABLE;
    sdram_init_struct.pipeline_read_delay = EXMC_PIPELINE_DELAY_1_CK_EXMC;
    sdram_init_struct.timing = &sdram_timing_init_struct;
    /* EXMC SDRAM bank initialization */
    exmc_sdram_init(&sdram_init_struct);

5.配置命令寄存器

 /* step 3 : configure CKE high command---------------------------------------*/
    sdram_command_init_struct.command = EXMC_SDRAM_CLOCK_ENABLE;
    sdram_command_init_struct.bank_select = bank_select;
    sdram_command_init_struct.auto_refresh_number = EXMC_SDRAM_AUTO_REFLESH_1_SDCLK;
    sdram_command_init_struct.mode_register_content = 0;
    /* wait until the SDRAM controller is ready */
    while((exmc_flag_get(sdram_device, EXMC_SDRAM_FLAG_NREADY) != RESET) && (timeout > 0)) {
        timeout--;
    }
    /* send the command */
    exmc_sdram_command_config(&sdram_command_init_struct);

    /* step 4 : insert 10ms delay----------------------------------------------*/
    _delay(100);

    /* step 5 : configure precharge all command----------------------------------*/
    sdram_command_init_struct.command = EXMC_SDRAM_PRECHARGE_ALL;
    sdram_command_init_struct.bank_select = bank_select;
    sdram_command_init_struct.auto_refresh_number = EXMC_SDRAM_AUTO_REFLESH_1_SDCLK;
    sdram_command_init_struct.mode_register_content = 0;
    /* wait until the SDRAM controller is ready */
    timeout = SDRAM_TIMEOUT;
    while((exmc_flag_get(sdram_device, EXMC_SDRAM_FLAG_NREADY) != RESET) && (timeout > 0)) {
        timeout--;
    }
    /* send the command */
    exmc_sdram_command_config(&sdram_command_init_struct);

    /* step 6 : configure Auto-Refresh command-----------------------------------*/
    sdram_command_init_struct.command = EXMC_SDRAM_AUTO_REFRESH;
    sdram_command_init_struct.bank_select = bank_select;
    sdram_command_init_struct.auto_refresh_number = EXMC_SDRAM_AUTO_REFLESH_8_SDCLK;
    sdram_command_init_struct.mode_register_content = 0;
    /* wait until the SDRAM controller is ready */
    timeout = SDRAM_TIMEOUT;
    while((exmc_flag_get(sdram_device, EXMC_SDRAM_FLAG_NREADY) != RESET) && (timeout > 0)) {
        timeout--;
    }
    /* send the command */
    exmc_sdram_command_config(&sdram_command_init_struct);

    /* step 7 : configure load mode register command-----------------------------*/
    /* program mode register */
    command_content = (uint32_t)SDRAM_MODEREG_BURST_LENGTH_1        |
                      SDRAM_MODEREG_BURST_TYPE_SEQUENTIAL   |
                      SDRAM_MODEREG_CAS_LATENCY_3           |
                      SDRAM_MODEREG_OPERATING_MODE_STANDARD |
                      SDRAM_MODEREG_WRITEBURST_MODE_SINGLE;

    sdram_command_init_struct.command = EXMC_SDRAM_LOAD_MODE_REGISTER;
    sdram_command_init_struct.bank_select = bank_select;
    sdram_command_init_struct.auto_refresh_number = EXMC_SDRAM_AUTO_REFLESH_1_SDCLK;
    sdram_command_init_struct.mode_register_content = command_content;

    /* wait until the SDRAM controller is ready */
    timeout = SDRAM_TIMEOUT;
    while((exmc_flag_get(sdram_device, EXMC_SDRAM_FLAG_NREADY) != RESET) && (timeout > 0)) {
        timeout--;
    }
    /* send the command */
    exmc_sdram_command_config(&sdram_command_init_struct);

6.设置自动刷新寄存器，等待控制器准备好



    /* step 8 : set the auto-refresh rate counter--------------------------------*/
    /* 64ms, 8192-cycle refresh, 64ms/8192=7.81us */
    /* SDCLK_Freq = SYS_Freq/2 */
    /* (7.81 us * SDCLK_Freq) - 20 */
    exmc_sdram_refresh_count_set(1542);

    /* wait until the SDRAM controller is ready */
    timeout = SDRAM_TIMEOUT;
    while((exmc_flag_get(sdram_device, EXMC_SDRAM_FLAG_NREADY) != RESET) && (timeout > 0)) {
        timeout--;
    }

7.SDRAM写函数

void sdram_writebuffer_8(uint32_t sdram_device, uint8_t *pbuffer, uint32_t write_addr, uint32_t byte_count_to_write)
{
    uint32_t temp_addr;

    /* select the base address according to EXMC_Bank */
    if(sdram_device == EXMC_SDRAM_DEVICE0) {
        temp_addr = SDRAM_DEVICE0_ADDR;
    } else {
        temp_addr = SDRAM_DEVICE1_ADDR;
    }

    /* while there is data to write */
    for(; byte_count_to_write != 0; byte_count_to_write--) {
        /* transfer data to the memory */
        *(uint8_t *)(temp_addr + write_addr) = *pbuffer++;

        /* increment the address */
        write_addr += 1;
    }
}

8.SDRAM读函数

void sdram_readbuffer_8(uint32_t sdram_device, uint8_t *pbuffer, uint32_t read_addr, uint32_t byte_count_to_read)
{
    uint32_t temp_addr;

    /* select the base address according to EXMC_Bank */
    if(sdram_device == EXMC_SDRAM_DEVICE0) {
        temp_addr = SDRAM_DEVICE0_ADDR;
    } else {
        temp_addr = SDRAM_DEVICE1_ADDR;
    }

    /* while there is data to read */
    for(; byte_count_to_read != 0; byte_count_to_read--) {
        /* read a byte from the memory */
        *pbuffer++ = *(uint8_t *)(temp_addr + read_addr);

        /* increment the address */
        read_addr += 1;
    }
}

9.主函数实现SDRAM初始化及写入数据并读出，比较写入与读出是否一样，不同结果控制不同指示灯。

int main(void)
{
    uint32_t i = 0;

    /* enable the CPU cache */
    cache_enable();

    /* initialize LEDs */
    gd_eval_led_init(LED1);
    gd_eval_led_init(LED2);

    /* configure systick clock */
    systick_config();

    /* configure the USART */
    gd_eval_com_init(EVAL_COM);

    /* configure the EXMC access mode */
    exmc_synchronous_dynamic_ram_init(EXMC_SDRAM_DEVICE0);

    printf("\r\nSDRAM initialized!");
    delay_1ms(1000);

    /* fill txbuffer */
    fill_buffer(txbuffer, BUFFER_SIZE, 0x0000);

    /* write data to SDRAM */
    sdram_writebuffer_8(EXMC_SDRAM_DEVICE0, txbuffer, WRITE_READ_ADDR, BUFFER_SIZE);

    printf("\r\nSDRAM write data completed!");
    delay_1ms(1000);

    /* read data from SDRAM */
    sdram_readbuffer_8(EXMC_SDRAM_DEVICE0, rxbuffer, WRITE_READ_ADDR, BUFFER_SIZE);

    printf("\r\nSDRAM read data completed!");
    delay_1ms(1000);

    printf("\r\nCheck the data!");
    delay_1ms(1000);

    /* compare two buffers */
    for(i = 0; i < BUFFER_SIZE; i++) {
        if(rxbuffer[i] != txbuffer[i]) {
            writereadstatus ++;
            break;
        }
    }

    if(writereadstatus) {
        printf("\r\nSDRAM test failed!");

        /* failure, light on LED2 */
        gd_eval_led_on(LED2);
    } else {
        printf("\r\nSDRAM test succeeded!");
        #if 0
        delay_1ms(1000);
        printf("\r\nThe data is:\r\n");
        delay_1ms(1000);
        for(i = 0; i < BUFFER_SIZE; i++) {
            printf("%6x", rxbuffer[i]);
            if(((i + 1) % 16) == 0) {
                printf("\r\n");
            }
        }
        #endif
        /* success, light on LED1 */
        gd_eval_led_on(LED1);
    }

    while(1) {
    }
}

三.编译烧录测验

编译烧录查看日志如下:

图3:SDRAM读写日志

至此实现对SDRAM的读写功能，对于拓展RAM应用是挺有用的。

wangerxian

SDRAM配置完成了，就等于是单片机自己的RAM了~

dirty

wangerxian 发表于 2024-5-23 18:42 SDRAM配置完成了，就等于是单片机自己的RAM了~

是的，地址映射下

【兆易GD32H759I-EVAL】--7.SDRAM读写 [复制链接]

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