本帖最后由 ddllxxrr 于 2014-12-24 19:56 编辑
上一篇是USART利用板载的DEBG来输出的，这里我想用我从淘宝搞的中九下载线来完成串口输出的功能。
Atmel ASF,是靠MUX就是复用器来重新选则管脚功能的。
打开上个例子的程序可以得到：
- config_usart.mux_setting = EDBG_CDC_SERCOM_MUX_SETTING;
- 42. config_usart.pinmux_pad0 = EDBG_CDC_SERCOM_PINMUX_PAD0;
- 43. config_usart.pinmux_pad1 = EDBG_CDC_SERCOM_PINMUX_PAD1;
- 44. config_usart.pinmux_pad2 = EDBG_CDC_SERCOM_PINMUX_PAD2;
- 45. config_usart.pinmux_pad3 = EDBG_CDC_SERCOM_PINMUX_PAD3;
- 46. while (usart_init(&usart_instance, EDBG_CDC_MODULE, &config_usart) != STATUS_OK)
- 47. { }
- 48. usart_enable(&usart_instance);
这一句就是选择USART的复用功能到哪个UART口。
而后边的
42. config_usart.pinmux_pad0 = EDBG_CDC_SERCOM_PINMUX_PAD0;
43. config_usart.pinmux_pad1 = EDBG_CDC_SERCOM_PINMUX_PAD1;
44. config_usart.pinmux_pad2 = EDBG_CDC_SERCOM_PINMUX_PAD2;
45. config_usart.pinmux_pad3 = EDBG_CDC_SERCOM_PINMUX_PAD3;
这些都在samd21_xplained_pro.h中定义好了。
所以我只要换，这几个命令行就可以了。我就可以把我的串口线用上了，呵呵！！！！
程序清单：
- /**
- * \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";
- usart_write_buffer_wait(&usart_instance, string, sizeof(string));
- uint16_t temp;
- while (true)
- {
- if (usart_read_wait(&usart_instance, &temp) == STATUS_OK)
- { while (usart_write_wait(&usart_instance, temp) != STATUS_OK)
- { }
- }
- }
- }
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