本帖最后由 ddllxxrr 于 2014-12-25 22:17 编辑
接上贴哈，上贴向串口发了一串字符串。我今天苦想了半天，就象发一个字符终于搞定哈
首先接着昨天的程序，我加了我要发的一个变量，把它赋值为0x55,为什么要用0x55，因为它是01准确间隔，用它的可以看出速率准不谁！！！！！
我加的只有两句：其它不变
uint8_t mystring = 0x55;
usart_write_buffer_wait(&usart_instance, string, sizeof(string));
我为什么这么做呢，我是想往printf上靠，究竟能不能实现，且听下回分解。
程序清单如下：
- /**
- * \file
- *
- * \brief Empty user application template
- *
- */
- /**
- * \mainpage User Application template doxygen documentation
- *
- * \par Empty user application template
- *
- * This is a bare minimum user application template.
- *
- * For documentation of the board, go \ref group_common_boards "here" for a link
- * to the board-specific documentation.
- *
- * \par Content
- *
- * -# Include the ASF header files (through asf.h)
- * -# Minimal main function that starts with a call to system_init()
- * -# Basic usage of on-board LED and button
- * -# "Insert application code here" comment
- *
- */
- /*
- * Include header files for all drivers that have been imported from
- * Atmel Software Framework (ASF).
- */
- #include <asf.h>
- void configure_usart(void);
- struct usart_module usart_instance;
- void configure_usart(void)
- {
- struct usart_config config_usart;
- usart_get_config_defaults(&config_usart);
- config_usart.baudrate = 9600;
- config_usart.mux_setting = EXT3_UART_SERCOM_MUX_SETTING;
- config_usart.pinmux_pad0 = EXT3_UART_SERCOM_PINMUX_PAD0;
- config_usart.pinmux_pad1 = EXT3_UART_SERCOM_PINMUX_PAD1;
- config_usart.pinmux_pad2 = EXT3_UART_SERCOM_PINMUX_PAD2;
- config_usart.pinmux_pad3 = EXT3_UART_SERCOM_PINMUX_PAD3;
- while (usart_init(&usart_instance, EXT3_UART_MODULE, &config_usart) != STATUS_OK)
- { }
- usart_enable(&usart_instance);
- }
- int main (void)
- {
- system_init();
- configure_usart();
- uint8_t string[] = "Hello World!\r\n";
- uint8_t mystring = 0x55;
- usart_write_buffer_wait(&usart_instance, string, sizeof(string));
- uint16_t temp;
- while (true)
- {
- usart_write_buffer_wait(&usart_instance, &mystring, sizeof( mystring));
- if (usart_read_wait(&usart_instance, &temp) == STATUS_OK)
- { while (usart_write_wait(&usart_instance, temp) != STATUS_OK)
- { }
- }
- }
- }
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