訪問內存映射的I / O

Question

我對嵌入式系統編程非常陌生，我只需要學習如何通過c ++代碼操縱給定的代碼即可。

鑒於：

電機1映射到0x60000000

電機2映射到0x50000000

以下是當前32位寄存器的定義

REGISTER NAME            |     BYTE OFFSET        |     NOTES
----------------------------------------------------------------------
motor_interrupt               0x00                 service interrupts

motor_status                  0x01                 enable on demand access to status elements
motor_command                 0x02                 enable command of the motor



REGISTER NAME           |   NAME   |  BITS   | ACCESS TYPE   | DESC 
----------------------------------------------------------------------------------

motor_interrupt_register
                           CLOSED      0          R/W         high when motor transitions to CLOSED position
                           OPEN        1          R/W         high when motor transitions to OPEN position
                           RESERVED    2.31       N/A         reserved for future use

motor_status        

                           SPEED       0.2         R          speed in counts/seconds
                           STATE        3          R          current state of motor
                           POSITION    4.13        R          current position of the motor
                           RESERVED    14.31       n/a         reserved for future use

我發現很難使用給定​​的示例代碼查看C ++代碼，這時我知道我需要訪問register_name並將其位設置為執行特定任務，或者讀取寄存器名稱以獲取狀態。

我想如果在C ++代碼中使用它，我會更加理解。 給定的是一個自動門系統（我沒有寫按鈕的詳細信息）。 我需要在c ++中訪問register_name或byte_offset嗎？

非常感謝您的幫助

Answer 1

讀取中斷/狀態寄存器的C / C ++示例：

volatile uint32_t * const motor1 = (uint32_t *)0x60000000; // base addresses for motors 1 and 2
volatile uint32_t * const motor2 = (uint32_t *)0x50000000;

enum  // register offsets from base address
{
    motor_interrupt, // 0x00 - service interrupts
    motor_status,    // 0x01 - enable on demand access to status elements
    motor_command    // 0x02 - enable command of the motor
}

// read status/interrupt registers

uint32_t current_int_1 = motor1[motor_interrupt];
uint32_t current_int_2 = motor2[motor_interrupt];

uint32_t current_status_1 = motor1[motor_status];
uint32_t current_status_2 = motor2[motor_status];

類似於將32位值寫入命令寄存器：

motor1[motor_command] = 0x8000 | (0x12 << 6) | 0x01;
motor2[motor_command] = 0x0;