problem with UART receiving - IDLE low all time
Hi,
I'm developing STM32G031 UARTs using registers and the CMSIS library. I’m using NUCLEO-G031K8 UART2 over an embedded STLINK/V3 on board and UART1 over an external CP210x UAR/USB adapter. I have a problem receiving data to UART1. No problem to receive data to UART2. Also both UARTs transmissions are working properly. I’m using the same configuration:
// USART1_TX = PA9
// USART1_RX = PA10
// USART2_TX = PA2
// USART2_RX = PA3
void my_uart1_conf ( void )
{
RCC->IOPENR |= RCC_IOPENR_GPIOAEN ; // Activate clock in GPIOA
GPIOA->MODER &= ~GPIO_MODER_MODE9_0 ; // Set Alternate Function (AF) for USART1_TX
GPIOA->MODER &= ~GPIO_MODER_MODE10_0 ; // Set Alternate Function (AF) for USART1_RX
GPIOA->AFR[1] |= GPIO_AFRH_AFSEL9_0 ; // AFRH is AFR[1]. Choose AF1
GPIOA->AFR[1] |= GPIO_AFRH_AFSEL10_0 ; // AFRH is AFR[1]. Choose AF1
GPIOA->OTYPER |= GPIO_OTYPER_OT10 ; // Choose Open_drain for RX to avoid P-MOS transistors issues
//GPIOA->PUPDR |= GPIO_PUPDR_PUPD10_1 ; // Rx Pull-up
RCC->IOPENR |= RCC_IOPENR_GPIOAEN ; // Activate clock in GPIOA
RCC->APBENR2 |= RCC_APBENR2_USART1EN ;
USART1->BRR = (uint16_t) ( 16000000 / 115200 ) ; // Activate clock for UART
USART1->CR1 |= USART_CR1_UE ;
USART1->CR1 |= USART_CR1_TE ;
USART1->CR1 |= USART_CR1_RE ;
}
void my_uart2_conf ( void )
{
RCC->IOPENR |= RCC_IOPENR_GPIOAEN ; // Activate clock in GPIOA
GPIOA->MODER &= ~GPIO_MODER_MODE2_0 ; // Set Alternate Function (AF) for USART2_TX
GPIOA->MODER &= ~GPIO_MODER_MODE3_0 ; // Set Alternate Function (AF) for USART2_RX
GPIOA->AFR[0] |= GPIO_AFRL_AFSEL2_0 ; // AFRL is AFR[0]. Choose AF1
GPIOA->AFR[0] |= GPIO_AFRL_AFSEL3_0 ; // AFRL is AFR[0]. Choose AF1
GPIOA->OTYPER |= GPIO_OTYPER_OT3 ; // Choose Open_drain for RX to avoid P-MOS transistors issues
RCC->IOPENR |= RCC_IOPENR_GPIOAEN ; // Activate clock in GPIOA
RCC->APBENR1 |= RCC_APBENR1_USART2EN ;
USART2->BRR = (uint16_t) ( 16000000 / 115200 ) ; // Activate clock for UART
USART2->CR1 |= USART_CR1_UE ;
USART2->CR1 |= USART_CR1_TE ;
USART2->CR1 |= USART_CR1_RE ;
}
In debug mode I verified GPIOA, UART1 and UART2 configuration and all registers’ values are the same. Exception is an ISR. There are following differences on ISRs register after UARTs configuration:
ISR Register | UART1 | UART2 |
CMF | 1 | 0 |
RXNE | 1 (goes 0 after some time) | 0 |
IDLE | 0 | 1 |
FE | 1 | 0 |
I tried also:
- change UART/USB adapter,
- different mix of UART1 OTYPER and PUPDR configuration,
without success.
Do you have an idea what I should change in GPIOA or USART1 configuration to be able to receive data to UART1?
V/r
yabool2001
