如何在汇编器中正确配置UART引脚

你好karlen。
 
 UART将其TX引脚配置为输出，但您必须设置Px_DDR，Px_CR1，Px_CR2和Px_ODR。
 原因很简单：与UART输出相关的Px_CR1位使能推/拉输出。
 如果你让UART默认配置它的TX输出引脚，它可能无法工作，因为它默认配置为开漏。
 设置Px_CR2也很有用，因为它控制高逻辑电平和低逻辑电平之间的转换速度。
 我建议你也将Px_ODR设置为TX空闲值，因为串行链路的另一端可能会检测到错误。
 
 我通常使用以下说明尽快配置所有引脚：
 
 MOV PA_ODR，＃％00100000
 MOV PA_DDR，＃％00100000
 MOV PA_CR1，＃％00100000
 MOV PA_CR2，＃％00100000
 
 但是，您的值可能不同，因为GPIO端口引脚在各种设备和/或应用程序需求之间共享。
 您还可以阅读STM8S系列参考手册和零件数据表，了解如何根据您的应用配置GPIO。
 
 问候
 
 EtaPhi



以下为原文





Hello karlen.

It's true that UART configures its TX pin as output, but you have to set Px_DDR, Px_CR1, Px_CR2 and Px_ODR too.
There is a simple reason: the bit of Px_CR1, which is related to UART output, enables the push/pull ouput.
If you let UART use its TX output pin as it's configured by default, it may not work because it's configured by default as open drain.
It's also useful to set Px_CR2, since it controls the speed of transitions between high and low logic levels.
I suggest you to set Px_ODR to the TX idle value too, because the other side of serial link may detect an error.

I usually configure all pins as soon as possible by using the following instructions:

MOV PA_ODR,#%00100000
MOV PA_DDR,#%00100000
MOV PA_CR1,#%00100000
MOV PA_CR2,#%00100000

However, your values may differ, because GPIO port pins are shared between various devices and/or application needs.
You may also read STM8S family reference manual and your part datasheet to understand how to configure GPIOs according to your application.

Regards

EtaPhi

直接操作寄存器就可以了的，找到寄存器的地址，使用指针进行操作