STM8S003F PD4不能用作GPIO

大家好！

我在异步模式下使用带有UART的STM8S003F微控制器。我想在推挽模式下使用UART1_CK引脚作为常规GPIO。这个引脚是PD4。外围设备配置如下：

PD_DDR_DDR4 = 1; //输出引脚PD4（EN）

PD_CR1_C14 = 1; //引脚PD4设置为P-P模式。
PD_CR2_C24 = 1; //引脚PD4可以运行高达10 MHz。

UART1_CR3_CKEN = 1;


在每次字节传输时，字节通过UART传输。然后我通过写入来禁用UART时钟输出：

UART1_CR3_CKEN = 0;


在那个引脚PD4变低，并写入

PD_ODR_ODR4 = 1;


什么都没有。 PD4引脚上不会出现高逻辑电平。

我的代码出了什么问题？我还应该检查什么？

#stm8s003f3＃pd4＃push-pull



以下为原文




Hi all!

I am using STM8S003F microcontroller with UART in async mode. I want to use UART1_CK pin as regular GPIO in push-pull mode. This pin is PD4. When peripherals are configured as below:

    PD_DDR_DDR4 = 1;   //  Pin PD4 (EN) is output

     PD_CR1_C14 = 1;    //  Pin PD4 is set to P-P mode.
     PD_CR2_C24 = 1;    //  Pin PD4 can run up to 10 MHz.

    UART1_CR3_CKEN = 1;


and byte is transmitted via UART,  on each byte transmission. Then I disable UART clock output by writing:

   UART1_CR3_CKEN = 0;


After that pin PD4 goes low, and writing  
   
  PD_ODR_ODR4 = 1;


gives nothing. High logic level doesn't appear on PD4 pin.  

What's wrong with my code? What else should I check?
  
#stm8s003f3 #pd4 #push-pull