Question

基本上,我正在从 RTOS 中的另一线索中获取数据。此数据是板上的一个针。所有 IO 端口都在iodefine.h 文件的结构/ 工会中。请参见 micrium 是如何制造它的 :

struct st_portd {
union {
    unsigned char BYTE;
    struct {
        unsigned char B0:1;
        unsigned char B1:1;
        unsigned char B2:1;
        unsigned char B3:1;
        unsigned char B4:1;
        unsigned char B5:1;
        unsigned char B6:1;
        unsigned char B7:1;
    } BIT;
} DDR;
unsigned char wk0[31];
union {
    unsigned char BYTE;
    struct {
        unsigned char B0:1;
        unsigned char B1:1;
        unsigned char B2:1;
        unsigned char B3:1;
        unsigned char B4:1;
        unsigned char B5:1;
        unsigned char B6:1;
        unsigned char B7:1;
    } BIT;
} DR;
unsigned char wk1[31];
union {
    unsigned char BYTE;
    struct {
        unsigned char B0:1;
        unsigned char B1:1;
        unsigned char B2:1;
        unsigned char B3:1;
        unsigned char B4:1;
        unsigned char B5:1;
        unsigned char B6:1;
        unsigned char B7:1;
    } BIT;
} PORT;
unsigned char wk2[31];
union {
    unsigned char BYTE;
    struct {
        unsigned char B0:1;
        unsigned char B1:1;
        unsigned char B2:1;
        unsigned char B3:1;
        unsigned char B4:1;
        unsigned char B5:1;
        unsigned char B6:1;
        unsigned char B7:1;
    } BIT;
} ICR;
unsigned char wk3[95];
union {
    unsigned char BYTE;
    struct {
        unsigned char B0:1;
        unsigned char B1:1;
        unsigned char B2:1;
        unsigned char B3:1;
        unsigned char B4:1;
        unsigned char B5:1;
        unsigned char B6:1;
        unsigned char B7:1;
    } BIT;
} PCR;
};

Very clever way if you ask me. So I save this pin as 2 chars in a struct, called Port and Pin.

struct StepperMotor {
  CPU_INT32U ID;
  CPU_CHAR *EnablePort;
  CPU_CHAR EnablePin;
  CPU_CHAR *DirectionPort;
  CPU_CHAR DirectionPin;
  CPU_CHAR *PulsePort;
  CPU_CHAR PulsePin;
};

我想这样用针子:

(struct st_portd)(steppermotor->PulsePort)->DR.BYTE ^= (1 << steppermotor->PulsePin);

steppermotor is the struct. Only with this way I get an error saying

在非结构或工会的某事中要求成员DR

How am I able to use the steppermotor->PulsePort->DR.BYTE without making a new variable for it? I hope anyone can help me!

Answer 1

由于您正在投下一个指针, 您应该将其投向一个结构, 而不是一个结构本身, 像这样的 :

((struct st_portd*)steppermotor->PulsePort)->DR.BYTE ^= (1 << steppermotor->PulsePin);

请注意,你的括号在错误的位置。

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