c - 将数据存储在程序存储器(PROGMEM)中并通过USB串行通信发送到puTTY屏幕

Question

我正在尝试将数据存储在 PROGMEM 中并稍后检索。然后通过 USB 串行通信将它们发送到屏幕。

int8_t serial_comm_write(const uint8_t *buffer, uint16_t size){
    //Here contains the code from the lib which I don't understand.
    //Basically, it's sending data (char *data) thru to screen. 
}

//This char *data could simply be:
// char *line = "This is stored in RAM"
//usb_send_info(line); would send the "line" to the screen.
void usb_send_info(char *data){
    serial_comm_write((uint8_t *)data, strlen(data));
}

//This doesn't work. I got a squiggly line saying "unknown register name 
//'r0'
//have no idea what it means. 
void usb_send_info_P(const char *data){
    while(pgm_read_byte(data) != 0x00){
        usb_send_info((pgm_read_byte(data++))); 
    }
}

const static char line1[] PROGMEM = "This is stored in flash mem";

usb_send_info_P(line1);

这根本行不通。有什么建议或替代方案吗？干杯。

Answer 1

usb_send_info 需要一个指向 SRAM 的 char*，而不是指向 FLASH (PROGMEM)。

usb_send_info((pgm_read_byte(data++))); 

pgm_read_byte 从给定的 PROGMEM 地址读取单个字节/字符。它不返回指针。所以这个函数调用没有意义。

如果你像这样改变 usb_send_info ，它应该可以工作:

void usb_send_info(char data) {
    serial_comm_write((uint8_t *)&data, 1);
}