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RIOT/cpu/lm4f120/periph/uart.c 3.45 KB
a752c7ab   elopes   add first test an...
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  /*
   * Copyright (C) 2015 Rakendra Thapa <rakendrathapa@gmail.com>
   *
   * This file is subject to the terms and conditions of the GNU Lesser General
   * Public License v2.1. See the file LICENSE in the top level directory for more
   * details.
   */
  
  /**
   * @ingroup     cpu_lm4f120
   * @ingroup     drivers_periph_uart
   * @{
   *
   * @file        uart.c
   * @brief       Implementation of the low-level UART driver for the LM4F120
   *
   * @author      Rakendra Thapa <rakendrathapa@gmail.com>
   *
   * @}
   */
  
  #include <stdint.h>
  
  #include "assert.h"
  #include "cpu.h"
  #include "periph/uart.h"
  #include "periph_conf.h"
  
  /**
   * @brief UART device configurations
   */
  static uart_isr_ctx_t config[UART_NUMOF];
  
  static int init_base(uart_t uart, uint32_t baudrate);
  
  /**
   * Configuring the UART console
   */
  int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
  {
      /* Check the arguments */
      assert(uart == 0);
      /* Check to make sure the UART peripheral is present */
      if(!ROM_SysCtlPeripheralPresent(SYSCTL_PERIPH_UART0)){
          return UART_NODEV;
      }
  
      int res = init_base(uart, baudrate);
      if(res != UART_OK){
          return res;
      }
  
  /* save callbacks */
      config[uart].rx_cb = rx_cb;
      config[uart].arg = arg;
  
  /*  ulBase = g_ulUARTBase[uart]; */
      switch (uart){
  #if UART_0_EN
          case UART_0:
              ROM_UARTTxIntModeSet(UART0_BASE, UART_TXINT_MODE_EOT);
              ROM_UARTFIFOLevelSet(UART0_BASE, UART_FIFO_TX4_8, UART_FIFO_RX4_8);
              ROM_UARTFIFOEnable(UART0_BASE);
  
              /* Enable the UART interrupt */
              NVIC_EnableIRQ(UART_0_IRQ_CHAN);
              /* Enable RX interrupt */
              UART0_IM_R = UART_IM_RXIM | UART_IM_RTIM;
              break;
  #endif
  #if UART_1_EN
          case UART_1:
              /* Enable the UART interrupt */
              NVIC_EnableIRQ(UART_1_IRQ_CHAN);
              break;
  #endif
      }
      return UART_OK;
  }
  
  static int init_base(uart_t uart, uint32_t baudrate)
  {
      switch(uart){
  #if UART_0_EN
          case UART_0:
              ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
              ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
              ROM_GPIOPinConfigure(GPIO_PA0_U0RX);
              ROM_GPIOPinConfigure(GPIO_PA1_U0TX);
              ROM_GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);
  
              ROM_UARTDisable(UART0_BASE);
              ROM_UARTConfigSetExpClk(UART0_BASE,ROM_SysCtlClockGet(), baudrate,
                      (UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE |
                       UART_CONFIG_WLEN_8));
  
  
              ROM_UARTEnable(UART0_BASE);
              break;
  #endif
          default:
              return UART_NODEV;
          }
      return UART_OK;
  }
  
  void uart_write(uart_t uart, const uint8_t *data, size_t len)
  {
      for (size_t i = 0; i < len; i++) {
          ROM_UARTCharPut(UART0_BASE, (char)data[i]);
      }
  }
  
  void uart_poweron(uart_t uart)
  {
      ROM_UARTEnable(UART0_BASE);
  }
  
  void uart_poweroff(uart_t uart)
  {
      ROM_UARTDisable(UART0_BASE);
  }
  
  /**
   * The UART interrupt handler.
   */
  void isr_uart0(void)
  {
      unsigned long ulStatus;
  
      ulStatus = ROM_UARTIntStatus(UART0_BASE, true);
      ROM_UARTIntClear(UART0_BASE, ulStatus);
  
      /* Are we interrupted due to a recieved character */
      if(ulStatus & (UART_INT_RX | UART_INT_RT))
      {
          while(ROM_UARTCharsAvail(UART0_BASE))
          {
              long lchar = ROM_UARTCharGetNonBlocking(UART0_BASE);
              config[UART_0].rx_cb(config[UART_0].arg, (uint8_t)lchar);
          }
      }
      cortexm_isr_end();
  }