c - USART communication on STM32L476G Discovery -

i have 2 boards: nucleo-f411re , stm32l467g discovery.

i need make virtual com connection between stm32l467g discovery , pc.

for nucleo : usart2 connected st-link, can communicate pc usart on usb. so, enable gpioa , usart2 clock. after that, configure gpioa link ports 2 , 3 on usart2, , works well! can receive characters on pc.

for stm32l467g discovery : stm32l467g discovery has usart2 on port 2 , 3 on gpioa too. but, in documentation, usart2 connected st-link usart2 on port 5 , 6 in gpiod. so, have modify souce code can't receive in computer..

check sources:

main.c

#include "stm32l4xx.h" #include "stm32l476g_discovery.h"   uart_handletypedef huart2; gpio_inittypedef gpio_initstruct; void configure_system_clock(void);  int main(void) {      hal_init(); // hal init      configure_system_clock(); // configure clock       __gpiod_clk_enable(); // enable gpiod clock     __usart2_clk_enable(); // enable usart2 clock       huart2.instance = usart2;     huart2.init.baudrate = 9600;     huart2.init.wordlength = uart_wordlength_8b;     huart2.init.stopbits = uart_stopbits_1;     huart2.init.parity = uart_parity_none;     huart2.init.mode = uart_mode_tx_rx;     huart2.init.hwflowctl = uart_hwcontrol_none;     hal_uart_init(&huart2);                /**usart2 gpio configuration             pa2     ------> usart2_tx             pa3     ------> usart2_rx             */     gpio_initstruct.pin = gpio_pin_5|gpio_pin_6;     gpio_initstruct.mode = gpio_mode_af_pp;     gpio_initstruct.pull = gpio_nopull;     gpio_initstruct.speed = gpio_speed_low;     gpio_initstruct.alternate = gpio_af7_usart2;     hal_gpio_init(gpioa, &gpio_initstruct);      char *msg = "hello you\n\r";            hal_uart_transmit(&huart2, (uint8_t*)msg, 15, 0xffff);       while (42); }  void configure_system_clock(void) {     rcc_oscinittypedef rcc_oscinitstruct;     rcc_clkinittypedef rcc_clkinitstruct;      __pwr_clk_enable();      __hal_pwr_voltagescaling_config(pwr_regulator_voltage_scale2);      rcc_oscinitstruct.oscillatortype = rcc_oscillatortype_hsi;     rcc_oscinitstruct.hsistate = rcc_hsi_on;     rcc_oscinitstruct.hsicalibrationvalue = 6;     rcc_oscinitstruct.pll.pllstate = rcc_pll_on;     rcc_oscinitstruct.pll.pllsource = rcc_pllsource_hsi;     rcc_oscinitstruct.pll.pllm = 8;     rcc_oscinitstruct.pll.plln = 336;     rcc_oscinitstruct.pll.pllp = rcc_pllp_div7;     rcc_oscinitstruct.pll.pllq = 7;     hal_rcc_oscconfig(&rcc_oscinitstruct);      rcc_clkinitstruct.clocktype = rcc_clocktype_sysclk|rcc_clocktype_pclk1;     rcc_clkinitstruct.sysclksource = rcc_sysclksource_pllclk;     rcc_clkinitstruct.ahbclkdivider = rcc_sysclk_div1;     rcc_clkinitstruct.apb1clkdivider = rcc_hclk_div2;     rcc_clkinitstruct.apb2clkdivider = rcc_hclk_div1;     hal_rcc_clockconfig(&rcc_clkinitstruct, flash_latency_2); } 

this code works fine on nucleo nucleo-f411re (but gpioa , port 2 , 3).

on stm32l467g discovery, code totaly fail, gpiod port 5 , 6 && gpioa port 2 , 3.

i can't see problem, can me please?

you initializing uart in main , ok, not catching way hal libraries want initialize peripheral's pin. should in hal_uart_mspinit() function can find in stm32f4_hal_msp.c file.

your main should this

hal_init(); // hal init  configure_system_clock(); // configure clock  huart2.instance = usart2; huart2.init.baudrate = 9600; huart2.init.wordlength = uart_wordlength_8b; huart2.init.stopbits = uart_stopbits_1; huart2.init.parity = uart_parity_none; huart2.init.mode = uart_mode_tx_rx; huart2.init.hwflowctl = uart_hwcontrol_none; hal_uart_init(&huart2);    hal_uart_transmit(&huart2, (uint8_t*)msg, 15, 0xffff); 

then in hal_uart_mspinit(uart_handletypedef* huart) should have this:

gpio_inittypedef gpio_initstruct; if(huart->instance==usart2) {  /* peripheral clock enable */  __usart2_clk_enable();  __gpiod_clk_enable();  /**usart2 gpio configuration  */ gpio_initstruct.pin = gpio_pin_5|gpio_pin_6; gpio_initstruct.mode = gpio_mode_af_pp; gpio_initstruct.pull = gpio_pullup; gpio_initstruct.speed = gpio_speed_high; gpio_initstruct.alternate = gpio_af7_usart2; hal_gpio_init(gpiod, &gpio_initstruct);      hal_nvic_setpriority(usart2_irqn, 0, 1);     hal_nvic_enableirq(usart2_irqn); } 

pay attention "gpio_pullup", suggest config gpio uart. have define uart handler in stm32f4_it.c file:

void usart2_irqhandler(void) {  hal_uart_irqhandler(&huart2); }