USART与stm8l连接总是取值0xff

你好Abhishek，
我没有对你的代码进行全面审查，但至少有一行看起来不对我。 USART1_DR寄存器只有一个字节，所以一次不能写入五个字节，就像你一样。在你的情况下，如果你试图写'HELLO'到这个寄存器，我希望你只发送最后一个字节（'O'，所以十六进制0x4F）。
发送五个字节的正确方法是逐字节发送它们，你需要确保在上一个字节已经发送之后开始发送下一个字节，例如像这样：
 
 
 
 
 
 
 
 
 
如果您想要完整的应用程序，您可以使用UART配置的最小代码，我在下面附加+数据传输代码。我检查了一下，它工作正常。引脚PC3在此用作UART_TX线。
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
最好的祝福
Szymon



以下为原文




Hello Abhishek,
I didn't make a full review of your code, but at least one line looks wrong to me. USART1_DR register has only one byte, so it is not possible to write to it five bytes in one time, like you did. In your case if you try to write 'HELLO' to this register, I would expect you will send just the last byte ('O', so hexadecimal 0x4F).
Proper way to send five bytes is to send them byte by byte and you need to make sure, that you start sending next byte after previous one is already sent, so for example like this:










If you would like to evalaute complete application, you can use the minimum code for UART configuration, which I attach below + the code for data transmission. I checked it on my side and it is working fine. Pin PC3 is used here as a UART_TX line.





  



  
















Best regards
Szymon

我尝试编译你的代码但不幸的是问题仍然存在
无论字符是什么，USART_DR寄存器只占用0xff值。
我正在附上截图。我也不明白的目的
line while（！（USART1-＆gt; SR＆amp; USART_SR_TC））。至于有什么不同
在我写的条件和你的条件之间。
问候，
阿布舍克
2017年6月21日星期三下午1:59，Szymon Panecki＆lt;



以下为原文





I tried compiling your code but unfortunately the problem still persists
that the USART_DR register takes only 0xff value whatever the character.
I'm attaching a screenshot. Also I didn't understand the purpose of the
line while(!(USART1->SR & USART_SR_TC)) . As in what's the difference
between the condition I had written and yours.
Regards,
Abhishek
On Wed, Jun 21, 2017 at 1:59 PM, Szymon Panecki <

上述代码的时钟配置（用于设置波特率）怎么样？



以下为原文




What about the clock configuration(for setting the baud rate) for the above code ?

你好Abhishek，
关于
 ：此行检查USART传输是否完成。建议使用它，因为在这种情况下你确定已发送了前一个字节，你可以写入新数据进行注册，这样你就不会遇到新数据在USART发送之前覆盖旧数据的情况。
关于我的应用程序中的时钟配置：如您所见，我没有配置时钟域，这意味着MCU使用默认设置：系统时钟等于HSI / 8 = 16 MHz / 8 = 2 MHz。
请在我的代码中找到附带的STVD项目。你能试试看吗？我在STM8L Discovery试剂盒（STM8L152C6T6）上进行了测试。
问候
Szymon



以下为原文




Hello Abhishek,
Regarding
: this line checks if USART transfer is complete. It is recommended to use it, because with this condition you are sure, that previous byte was sent and you can write new data to register, so you will not face the situation that new data overwrites old one before it is sent by USART.

Regarding clock configuration in my application: as you can see I don't configure the clock domain, which means that MCU uses default settings: system clock is equal to HSI / 8 = 16 MHz / 8 = 2 MHz.

Please find attached a STVD project with my code. Could you plese try it? I tested it on STM8L Discovery kit (STM8L152C6T6).

Regards

Szymon

好的，这是原因，但我仍然得到了错误的价值
USART_DR注册
2017年6月21日星期三下午3:55，Szymon Panecki＆lt;



以下为原文




Okay that's the reason but I'm still getting the wrong value in the
USART_DR register
On Wed, Jun 21, 2017 at 3:55 PM, Szymon Panecki <

这是您自己的代码的调试。为什么它适合你而不适合我？



以下为原文




This is debugging of your own code. Why is it working for you and not for me?

你不能像那样检查DR，它不像存储单元那样。除非您在外部回输输出，否则RECEIVE寄存器不会反映您在TRANSMIT寄存器中的内容。
等待寄存器为空，发送'U'字符，循环执行此操作，将示波器探针连接到TX引脚并查看信号，检查位时序等。



以下为原文




You can't inspect the DR like that, it doesn't act like a memory cell. Unless you loop-back the output externally, the RECEIVE register is not going to reflect what you put in the TRANSMIT register.
Wait for the register to be empty, and send a 'U' character, do this in a loop, attach a scope probe to the TX pin and review the signalling, check bit timing, etc.

你好克莱夫，我有点像业余爱好者，所以不能真正跟随最后一部分？你能详细说明吗？



以下为原文




Hello Clive,  I'm a bit of an amateur so couldn't really follow the last part? Could you please elaborate?