同样是做设计，他们的差别，不仅仅体现在技术水平上！
本帖最后由 nongfuxu 于 2021-5-6 16:16 编辑同样是做设计，他们的差别，不仅仅体现在技术水平上！
下面代码来自芯片厂家的驱动库函数
*=============================================================================
* Supported STM32F40xxx/41xxx devices
*-----------------------------------------------------------------------------
* System Clock source | PLL (HSE)
*-----------------------------------------------------------------------------
* SYSCLK(Hz) | 168000000
*-----------------------------------------------------------------------------
* HCLK(Hz) | 168000000
*-----------------------------------------------------------------------------
* AHB Prescaler | 1
*-----------------------------------------------------------------------------
* APB1 Prescaler | 4
*-----------------------------------------------------------------------------
* APB2 Prescaler | 2
*-----------------------------------------------------------------------------
* HSE Frequency(Hz) | 25000000
*-----------------------------------------------------------------------------
* PLL_M | 25
*-----------------------------------------------------------------------------
* PLL_N | 336
*-----------------------------------------------------------------------------
* PLL_P | 2
*-----------------------------------------------------------------------------
* PLL_Q | 7
*-----------------------------------------------------------------------------
* PLLI2S_N | NA
*-----------------------------------------------------------------------------
* PLLI2S_R | NA
*-----------------------------------------------------------------------------
* I2S input clock | NA
*-----------------------------------------------------------------------------
* VDD(V) | 3.3
*-----------------------------------------------------------------------------
* Main regulator output voltage | Scale1 mode
*-----------------------------------------------------------------------------
* Flash Latency(WS) | 5
*-----------------------------------------------------------------------------
上面是给出设置“ 系统频率函数 ” void SetSysClock(void)之前的注释。
static void SetSysClock(void)
{
/******************************************************************************/
/* PLL (clocked by HSE) used as System clock source */
/******************************************************************************/
__IO uint32_t StartUpCounter = 0, HSEStatus = 0;
/* Enable HSE */
RCC->CR |= ((uint32_t)RCC_CR_HSEON);
/* Wait till HSE is ready and if Time out is reached exit */
do
{
HSEStatus = RCC->CR & RCC_CR_HSERDY;
StartUpCounter++;
} while((HSEStatus == 0) && (StartUpCounter != HSE_STARTUP_TIMEOUT));
if ((RCC->CR & RCC_CR_HSERDY) != RESET)
{
HSEStatus = (uint32_t)0x01;
}
else
{
HSEStatus = (uint32_t)0x00;
}
if (HSEStatus == (uint32_t)0x01)
{
/* Select regulator voltage output Scale 1 mode */
RCC->APB1ENR |= RCC_APB1ENR_PWREN;
PWR->CR |= PWR_CR_VOS;
/* HCLK = SYSCLK / 1*/
RCC->CFGR |= RCC_CFGR_HPRE_DIV1;
#if defined (STM32F40_41xxx) || defined (STM32F427_437xx) || defined (STM32F429_439xx)
/* PCLK2 = HCLK / 2*/
RCC->CFGR |= RCC_CFGR_PPRE2_DIV2;
/* PCLK1 = HCLK / 4*/
RCC->CFGR |= RCC_CFGR_PPRE1_DIV4;
#endif /* STM32F40_41xxx || STM32F427_437x || STM32F429_439xx */
#if defined (STM32F401xx)
/* PCLK2 = HCLK / 2*/
RCC->CFGR |= RCC_CFGR_PPRE2_DIV1;
/* PCLK1 = HCLK / 4*/
RCC->CFGR |= RCC_CFGR_PPRE1_DIV2;
#endif /* STM32F401xx */
/* Configure the main PLL */
RCC->PLLCFGR = PLL_M | (PLL_N << 6) | (((PLL_P >> 1) -1) << 16) |
(RCC_PLLCFGR_PLLSRC_HSE) | (PLL_Q << 24);
/* Enable the main PLL */
RCC->CR |= RCC_CR_PLLON;
/* Wait till the main PLL is ready */
while((RCC->CR & RCC_CR_PLLRDY) == 0)
{
}
#if defined (STM32F427_437xx) || defined (STM32F429_439xx)
/* Enable the Over-drive to extend the clock frequency to 180 Mhz */
PWR->CR |= PWR_CR_ODEN;
while((PWR->CSR & PWR_CSR_ODRDY) == 0)
{
}
PWR->CR |= PWR_CR_ODSWEN;
while((PWR->CSR & PWR_CSR_ODSWRDY) == 0)
{
}
/* Configure Flash prefetch, Instruction cache, Data cache and wait state */
FLASH->ACR = FLASH_ACR_PRFTEN | FLASH_ACR_ICEN |FLASH_ACR_DCEN |FLASH_ACR_LATENCY_5WS;
#endif /* STM32F427_437x || STM32F429_439xx*/
#if defined (STM32F40_41xxx)
/* Configure Flash prefetch, Instruction cache, Data cache and wait state */
FLASH->ACR = FLASH_ACR_PRFTEN | FLASH_ACR_ICEN |FLASH_ACR_DCEN |FLASH_ACR_LATENCY_5WS;
#endif /* STM32F40_41xxx*/
#if defined (STM32F401xx)
/* Configure Flash prefetch, Instruction cache, Data cache and wait state */
FLASH->ACR = FLASH_ACR_PRFTEN | FLASH_ACR_ICEN |FLASH_ACR_DCEN |FLASH_ACR_LATENCY_2WS;
#endif /* STM32F401xx */
/* Select the main PLL as system clock source */
RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
RCC->CFGR |= RCC_CFGR_SW_PLL;
/* Wait till the main PLL is used as system clock source */
while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS ) != RCC_CFGR_SWS_PLL);
{
}
}
else
{ /* If HSE fails to start-up, the application will have wrong clock
configuration. User can add here some code to deal with this error */
}
} 本帖最后由 nongfuxu 于 2021-5-6 16:22 编辑
再看另外一家公司给出的驱动函数，注解能省则省。
======***前面没有注释***=======
static void SysClkConfig(void)
{
stc_clk_sysclk_cfg_t stcSysClkCfg;
stc_clk_xtal_cfg_t stcXtalCfg;
stc_clk_mpll_cfg_t stcMpllCfg;
MEM_ZERO_STRUCT(stcSysClkCfg);
MEM_ZERO_STRUCT(stcXtalCfg);
MEM_ZERO_STRUCT(stcMpllCfg);
/* Set bus clk div. */
stcSysClkCfg.enHclkDiv= ClkSysclkDiv1;// 100MHz
stcSysClkCfg.enExclkDiv = ClkSysclkDiv2;// 50MHz
stcSysClkCfg.enPclk0Div = ClkSysclkDiv1;// 100MHz
stcSysClkCfg.enPclk1Div = ClkSysclkDiv2;// 50MHz
stcSysClkCfg.enPclk2Div = ClkSysclkDiv4;// 25MHz
stcSysClkCfg.enPclk3Div = ClkSysclkDiv4;// 25MHz
stcSysClkCfg.enPclk4Div = ClkSysclkDiv2;// 50MHz
CLK_SysClkConfig(&stcSysClkCfg);
/* Switch system clock source to MPLL. */
/* Use Xtal as MPLL source. */
stcXtalCfg.enMode = ClkXtalModeOsc;
stcXtalCfg.enDrv = ClkXtalLowDrv;
stcXtalCfg.enFastStartup = Enable;
CLK_XtalConfig(&stcXtalCfg);
CLK_XtalCmd(Enable);
/* MPLL config. */
stcMpllCfg.pllmDiv = 1ul;
stcMpllCfg.plln =50ul;
stcMpllCfg.PllpDiv = 4ul;
stcMpllCfg.PllqDiv = 4ul;
stcMpllCfg.PllrDiv = 4ul;
CLK_SetPllSource(ClkPllSrcXTAL);
CLK_MpllConfig(&stcMpllCfg);
/* flash read wait cycle setting */
EFM_Unlock();
EFM_SetLatency(5ul);
EFM_Lock();
/* Enable MPLL. */
CLK_MpllCmd(Enable);
/* Wait MPLL ready. */
while(Set != CLK_GetFlagStatus(ClkFlagMPLLRdy))
{
;
}
/* Switch system clock source to MPLL. */
CLK_SetSysClkSource(CLKSysSrcMPLL);
} 再看下面一段代码，摘自驱动库串口例子程序
//初始化串口用端口 Initialize USART IO */
PORT_SetFunc(USART_RX_PORT, USART_RX_PIN, USART_RX_FUNC, Disable);//PortE
PORT_SetFunc(USART_TX_PORT, USART_TX_PIN, USART_TX_FUNC, Disable);
这是使用（使能），还是不用（禁止）呀？
PORT_SetFunc 函数原型
*******************************************************************************
** \brief Set Port Pin function
**
** \param enPort GPIO port index, This parameter can be
** any value of @ref en_port_t
** \param u16Pin GPIO pin index, This parameter can be
** any value of @ref en_pin_t
** \param enFuncSel Function selection, This parameter can be
** any value of @ref en_port_func_t
**
** \param enSubFunc The new state of the gpio sub-function.
** \arg Enable Enable.
** \arg Disable Disable.
**
** \retvalOk Set successful to corresponding pins
**
******************************************************************************/
en_result_t PORT_SetFunc(en_port_t enPort, uint16_t u16Pin, en_port_func_t enFuncSel,\
en_functional_state_t enSubFunc)
{
这个代码是GD32吗? nongfuxu 发表于 2021-5-6 17:00
再看下面一段代码，摘自驱动库串口例子程序
/* main function setting */
PFSRx->FSEL = enFuncSel;//功能选择寄存器:各端口的主功能配置
/* sub function enable setting */
PFSRx->BFE = (Enable == enSubFunc ? Enable : Disable); //功能选择寄存器:各端口的副功能配置
en_result_t PORT_SetFunc (...)
{
for (u8PinPos = 0u; u8PinPos < 16u; u8PinPos ++)
{
if (u16Pin & (uint16_t)(1ul<<u8PinPos))
{
PFSRx = (stc_port_pfsr_field_t *)((uint32_t)(&M4_PORT->PFSRA0) \
+ 0x40ul * enPort + 0x4ul * u8PinPos);
/* main function setting */
PFSRx->FSEL = enFuncSel;//功能选择寄存器（PFSRxy）
/* sub function enable setting */
PFSRx->BFE = (Enable == enSubFunc ? Enable : Disable);
}
}
}
其中功能选择寄存器:各端口的副功能配置，是不是用于在 “有些应用 情 况，需要将一个端口同时设成两种功能”场合？
PFSRx->BFE = (Enable == enSubFunc ? Enable : Disable); nongfuxu 发表于 2021-5-6 22:13
其中功能选择寄存器:各端口的副功能配置，是不是用于在 “有些应用 情 况，需要将一个端口同时设成两种功 ...
文档是可以省略的，写文档成本太高了。呵呵！ 华大的库吗？ 你觉得谁好，学谁的就完了 没有对比就没有伤害 现在代码大部分流行自注释了吧.
不过下面这写法个别地方有点容易产生歧义. 感谢楼主的分享，不错的想法。 感觉象是水文,如果真是水文,值"二毛五分钱",如果不是水文,请楼主海涵.要比较就要和更好的比较,和不如你的比较有什么意思?
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