, спасибо, но удалось решить проблему без использование библиотеки, на уровне регистров. (Кстати, откуда взять StdPeriphLib для STM32L0xx??? Я вот не нашел нигде.)
За решение спасибо компании ST, которая на странице микроконтроллера выложила сниппеты, среди которых я нашел код для работы с USART (там работа именно с регистрами).
Правда пока не вникал в него и не могу сказать где именно я ошибся. Как пойму где была ошибка в моем коде отпишусь.
Ниже приведу пример кода, который у меня заработал прямо сразу.
/**
******************************************************************************
* File 01_Transmitter/main.c
* Author MCD Application Team
* Version V1.1.1
* Date 04-March-2015
* Brief This code example shows how to configure the GPIOs and USART1
* in order to send bytes.
*
==============================================================================
##### RCC specific features #####
==============================================================================
[..] After reset the device is running from MSI (2 MHz) with Flash 0 WS,
and voltage scaling range is 2 (1.5V)
all peripherals are off except internal SRAM, Flash and SW-DP.
(+) There is no prescaler on High speed (AHB) and Low speed (APB) busses;
all peripherals mapped on these busses are running at MSI speed.
(+) The clock for all peripherals is switched off, except the SRAM and
FLASH.
(+) All GPIOs are in analog state, except the SW-DP pins which
are assigned to be used for debug purpose.
[..] Once the device started from reset, the user application has to:
(+) Configure the clock source to be used to drive the System clock
(if the application needs higher frequency/performance)
(+) Configure the System clock frequency and Flash settings
(+) Configure the AHB and APB busses prescalers
(+) Enable the clock for the peripheral(s) to be used
(+) Configure the clock source(s) for peripherals whose clocks are not
derived from the System clock (ADC, RTC/LCD, RNG and IWDG)
===============================================================================
##### MCU Resources #####
===============================================================================
- RCC
- GPIO PA9(USART1_TX),PA10(USART1_RX),PA0,PA5,PB4
- USART1
- EXTI
===============================================================================
##### How to use this example #####
===============================================================================
- this file must be inserted in a project containing the following files :
o system_stm32l0xx.c, startup_stm32l053xx.s
o stm32l0xx.h to get the register definitions
o CMSIS files
===============================================================================
##### How to test this example #####
===============================================================================
- Plug cable " USB to TTL 3V3 " (from FTDIChip), to GND, PA9 and PA10.
- Launch serial communication SW on PC
- Launch the program
- Press the user button
- "ST" is transmit to PC
- The green LED should blink if everything goes well
(transmit request)
*
******************************************************************************
* Attention
*
* <h2><center>© COPYRIGHT 2015 STMicroelectronics</center></h2>
*
* Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
* You may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
*
http://www.st.com/software_license_agreement_liberty_v2 *
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************
*/
/* Includes ------------------------------------------------------------------*/
#include "stm32l0xx.h"
/** STM32L0_Snippets
*
*/
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Time-out values */
#define HSI_TIMEOUT_VALUE ((uint32_t)100) /* 100 ms */
#define PLL_TIMEOUT_VALUE ((uint32_t)100) /* 100 ms */
#define CLOCKSWITCH_TIMEOUT_VALUE ((uint32_t)5000) /* 5 s */
/* Delay value : short one is used for the error coding, long one (~1s) in case
of no error or between two bursts */
#define SHORT_DELAY 200
#define LONG_DELAY 1000
/* Error codes used to make the red led blinking */
#define ERROR_USART_TRANSMIT 0x01
#define ERROR_HSI_TIMEOUT 0x02
#define ERROR_PLL_TIMEOUT 0x03
#define ERROR_CLKSWITCH_TIMEOUT 0x04
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
static __IO uint32_t Tick;
volatile uint16_t error = 0; //initialized at 0 and modified by the functions
uint8_t send = 0;
const uint8_t stringtosend[] = "ST\n";
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
void Configure_GPIO_LED(void);
void Configure_GPIO_USART1(void);
void Configure_USART1(void);
void Configure_GPIO_Button(void);
void Configure_EXTI(void);
/* Private functions ---------------------------------------------------------*/
/**
* Brief Main program.
* Param None
* Retval None
*/
int main(void)
{
/*!< At this stage the microcontroller clock setting is already configured,
this is done through SystemInit() function which is called from startup
file (startup_stm32l0xx.s) before to branch to application main.
To reconfigure the default setting of SystemInit() function, refer to
system_stm32l0xx.c file
*/
SysTick_Config(2000); /* 1ms config */
SystemClock_Config();
Configure_GPIO_LED();
if (error != 0)
{
while(1) /* endless loop */
{
}
}
SysTick_Config(16000); /* 1ms config */
Configure_GPIO_USART1();
Configure_USART1();
Configure_GPIO_Button();
Configure_EXTI();
/* Start transmission in button IRQ handler */
while (1) /* Infinite loop */
{
}
}
/**
* Brief This function configures the system clock @16MHz and voltage scale 1
* assuming the registers have their reset value before the call.
* POWER SCALE = RANGE 1
* SYSTEM CLOCK = PLL MUL8 DIV2
* PLL SOURCE = HSI/4
* FLASH LATENCY = 0
* Param None
* Retval None
*/
__INLINE void SystemClock_Config(void)
{
uint32_t tickstart;
/* (1) Enable power interface clock */
/* (2) Select voltage scale 1 (1.65V - 1.95V)
i.e. (01) for VOS bits in PWR_CR */
/* (3) Enable HSI divided by 4 in RCC-> CR */
/* (4) Wait for HSI ready flag and HSIDIV flag */
/* (5) Set PLL on HSI, multiply by 8 and divided by 2 */
/* (6) Enable the PLL in RCC_CR register */
/* (7) Wait for PLL ready flag */
/* (8) Select PLL as system clock */
/* (9) Wait for clock switched on PLL */
RCC->APB1ENR |= (RCC_APB1ENR_PWREN); /* (1) */
PWR->CR = (PWR->CR & ~(PWR_CR_VOS)) | PWR_CR_VOS_0; /* (2) */
RCC->CR |= RCC_CR_HSION | RCC_CR_HSIDIVEN; /* (3) */
tickstart = Tick;
while ((RCC->CR & (RCC_CR_HSIRDY |RCC_CR_HSIDIVF)) != (RCC_CR_HSIRDY |RCC_CR_HSIDIVF)) /* (4) */
{
if ((Tick - tickstart ) > HSI_TIMEOUT_VALUE)
{
error = ERROR_HSI_TIMEOUT; /* Report an error */
return;
}
}
RCC->CFGR |= RCC_CFGR_PLLSRC_HSI | RCC_CFGR_PLLMUL8 | RCC_CFGR_PLLDIV2; /* (5) */
RCC->CR |= RCC_CR_PLLON; /* (6) */
tickstart = Tick;
while ((RCC->CR & RCC_CR_PLLRDY) == 0) /* (7) */
{
if ((Tick - tickstart ) > PLL_TIMEOUT_VALUE)
{
error = ERROR_PLL_TIMEOUT; /* Report an error */
return;
}
}
RCC->CFGR |= RCC_CFGR_SW_PLL; /* (8) */
tickstart = Tick;
while ((RCC->CFGR & RCC_CFGR_SWS_PLL) == 0) /* (9) */
{
if ((Tick - tickstart ) > CLOCKSWITCH_TIMEOUT_VALUE)
{
error = ERROR_CLKSWITCH_TIMEOUT; /* Report an error */
return;
}
}
}
/**
* Brief This function enables the peripheral clocks on GPIO port A and B,
* configures GPIO PB4 in output mode for the Green LED pin,
* configures GPIO PA5 in output mode for the Red LED pin,
* Param None
* Retval None
*/
__INLINE void Configure_GPIO_LED(void)
{
/* (1) Enable the peripheral clock of GPIOA and GPIOB */
/* (2) Select output mode (01) on GPIOA pin 5 */
/* (3) Select output mode (01) on GPIOB pin 4 */
RCC->IOPENR |= RCC_IOPENR_GPIOAEN | RCC_IOPENR_GPIOBEN; /* (1) */
GPIOA->MODER = (GPIOA->MODER & ~(GPIO_MODER_MODE5))
| (GPIO_MODER_MODE5_0); /* (2) */
GPIOB->MODER = (GPIOB->MODER & ~(GPIO_MODER_MODE4))
| (GPIO_MODER_MODE4_0); /* (3) */
}
/**
* Brief This function :
- Enables GPIO clock
- Configures the USART1 pins on GPIO PA9 PA10
* Param None
* Retval None
*/
__INLINE void Configure_GPIO_USART1(void)
{
/* Enable the peripheral clock of GPIOA */
RCC->IOPENR |= RCC_IOPENR_GPIOAEN;
/* GPIO configuration for USART1 signals */
/* (1) Select AF mode (10) on PA9 and PA10 */
/* (2) AF4 for USART1 signals */
GPIOA->MODER = (GPIOA->MODER & ~(GPIO_MODER_MODE9|GPIO_MODER_MODE10))\
| (GPIO_MODER_MODE9_1 | GPIO_MODER_MODE10_1); /* (1) */
GPIOA->AFR[1] = (GPIOA->AFR[1] &~ (0x00000FF0))\
| (4 << (1 * 4)) | (4 << (2 * 4)); /* (2) */
}
/**
* Brief This function configures USART1.
* Param None
* Retval None
*/
__INLINE void Configure_USART1(void)
{
/* Enable the peripheral clock USART1 */
RCC->APB2ENR |= RCC_APB2ENR_USART1EN;
/* Configure USART1 */
/* (1) oversampling by 16, 9600 baud */
/* (2) 8 data bit, 1 start bit, 1 stop bit, no parity */
USART1->BRR = 160000 / 96; /* (1) */
USART1->CR1 = USART_CR1_TE | USART_CR1_UE; /* (2) */
/* polling idle frame Transmission */
while((USART1->ISR & USART_ISR_TC) != USART_ISR_TC)
{
/* add time out here for a robust application */
}
USART1->ICR |= USART_ICR_TCCF;/* clear TC flag */
USART1->CR1 |= USART_CR1_TCIE;/* enable TC interrupt */
/* Configure IT */
/* (3) Set priority for USART1_IRQn */
/* (4) Enable USART1_IRQn */
NVIC_SetPriority(USART1_IRQn, 0); /* (3) */
NVIC_EnableIRQ(USART1_IRQn); /* (4) */
}
/**
* Brief This function :
- Enables GPIO clock
- Configures the Push Button GPIO PA0
* Param None
* Retval None
*/
__INLINE void Configure_GPIO_Button(void)
{
/* Enable the peripheral clock of GPIOA */
RCC->IOPENR |= RCC_IOPENR_GPIOAEN;
/* Select mode */
/* Select input mode (00) on PA0 */
GPIOA->MODER = (GPIOA->MODER & ~(GPIO_MODER_MODE0));
}
/**
* Brief This function configures EXTI.
* Param None
* Retval None
*/
__INLINE void Configure_EXTI(void)
{
/* Configure Syscfg, exti and nvic for pushbutton PA0 */
/* (1) PA0 as source input */
/* (2) Unmask port 0 */
/* (3) Rising edge */
/* (4) Set priority */
/* (5) Enable EXTI0_1_IRQn */
SYSCFG->EXTICR[0] = (SYSCFG->EXTICR[0] & ~SYSCFG_EXTICR1_EXTI0) | SYSCFG_EXTICR1_EXTI0_PA; /* (1) */
EXTI->IMR |= EXTI_IMR_IM0; /* (2) */
EXTI->RTSR |= EXTI_RTSR_TR0; /* (3) */
NVIC_SetPriority(EXTI0_1_IRQn, 0); /* (4) */
NVIC_EnableIRQ(EXTI0_1_IRQn); /* (5) */
}
/******************************************************************************/
/* Cortex-M0 Plus Processor Exceptions Handlers */
/******************************************************************************/
/**
* Brief This function handles NMI exception.
* Param None
* Retval None
*/
void NMI_Handler(void)
{
}
/**
* Brief This function handles Hard Fault exception.
* Param None
* Retval None
*/
void HardFault_Handler(void)
{
/* Go to infinite loop when Hard Fault exception occurs */
while (1)
{
}
}
/**
* Brief This function handles SVCall exception.
* Param None
* Retval None
*/
void SVC_Handler(void)
{
}
/**
* Brief This function handles PendSVC exception.
* Param None
* Retval None
*/
void PendSV_Handler(void)
{
}
/**
* Brief This function handles SysTick Handler.
* It toggles the green led if the action has been performed correctly
* and toggles the red led coding the error number
* Param None
* Retval None
*/
void SysTick_Handler(void)
{
static uint32_t long_counter = LONG_DELAY;
static uint32_t short_counter = SHORT_DELAY;
static uint16_t error_temp = 0;
Tick++;
if (long_counter-- == 0)
{
if(error == 0)
{
/* the following instruction can only be used if no ISR modifies GPIOC ODR
either by writing directly it or by using GPIOC BSRR or BRR
else a toggle mechanism must be implemented using GPIOC BSRR and/or BRR
*/
GPIOB->ODR ^= (1 << 4);//toggle green led on PB4
long_counter = LONG_DELAY;
}
else if (error != 0xFF)
{
/* red led blinks according to the code error value */
error_temp = (error << 1) - 1;
short_counter = SHORT_DELAY;
long_counter = LONG_DELAY << 1;
GPIOA->BSRR = (1 << 5); //set red led on PA5
GPIOB->BRR = (1 << 4); //switch off green led on PB4
}
}
if (error_temp > 0)
{
if (short_counter-- == 0)
{
GPIOA->ODR ^= (1 << 5); //toggle red led
short_counter = SHORT_DELAY;
error_temp--;
}
}
}
/******************************************************************************/
/* STM32L0xx Peripherals Interrupt Handlers */
/* Add here the Interrupt Handler for the used peripheral(s) (PPP), for the */
/* available peripheral interrupt handler's name please refer to the startup */
/* file (startup_stm32l0xx.s). */
/******************************************************************************/
/**
* Brief This function handles EXTI 0 1 interrupt request.
* Param None
* Retval None
*/
void EXTI0_1_IRQHandler(void)
{
if((EXTI->PR & EXTI_PR_PR0) == EXTI_PR_PR0)
{
/* Clear EXTI 0 flag */
EXTI->PR |= EXTI_PR_PR0;
/* start USART transmission */
USART1->TDR = stringtosend[send++]; /* Will inititiate TC if TXE */
}
}
/**
* Brief This function handles USART1 interrupt request.
* Param None
* Retval None
*/
void USART1_IRQHandler(void)
{
if((USART1->ISR & USART_ISR_TC) == USART_ISR_TC)
{
if(send == sizeof(stringtosend))
{
send=0;
USART1->ICR |= USART_ICR_TCCF; /* Clear transfer complete flag */
GPIOB->ODR ^= (1 << 4); /* Toggle green led on PB4 */
}
else
{
/* clear transfer complete flag and fill TDR with a new char */
USART1->TDR = stringtosend[send++];
}
}
else
{
error = ERROR_USART_TRANSMIT; /* Report an error */
NVIC_DisableIRQ(USART1_IRQn); /* Disable USART1_IRQn */
}
}
/************************ © COPYRIGHT STMicroelectronics *****END OF FILE****/
Clock порта в этом контроллере запускается не в регистре AHBENR, а в регистре IOPENR. Соответственно должно быть не так: