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AT32F437VM SPI驱动AT7456E OSD芯片

作者：在线问答5 | 2024-06-25 08:04:43

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at7456e

        上篇文章讲了BF固件中关于OSD的代码部分，今天来看一下硬件部分。    

        使用AT的芯片配置SPI和OSD芯片通讯。

            

先配置一下AT32F437的时钟：

  1. /**
  2.   **************************************************************************
  3.   * @file     at32f435_437_clock.c
  4.   * @brief    system clock config program
  5.   **************************************************************************
  6.   *                       Copyright notice & Disclaimer
  7.   *
  8.   * The software Board Support Package (BSP) that is made available to 
  9.   * download from Artery official website is the copyrighted work of Artery. 
  10.   * Artery authorizes customers to use, copy, and distribute the BSP 
  11.   * software and its related documentation for the purpose of design and 
  12.   * development in conjunction with Artery microcontrollers. Use of the 
  13.   * software is governed by this copyright notice and the following disclaimer.
  14.   *
  15.   * THIS SOFTWARE IS PROVIDED ON "AS IS" BASIS WITHOUT WARRANTIES,
  16.   * GUARANTEES OR REPRESENTATIONS OF ANY KIND. ARTERY EXPRESSLY DISCLAIMS,
  17.   * TO THE FULLEST EXTENT PERMITTED BY LAW, ALL EXPRESS, IMPLIED OR
  18.   * STATUTORY OR OTHER WARRANTIES, GUARANTEES OR REPRESENTATIONS,
  19.   * INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY,
  20.   * FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
  21.   *
  22.   **************************************************************************
  23.   */
  24.  
  25. /* includes ------------------------------------------------------------------*/
  26. #include "at32f435_437_clock.h"
  27.  
  28. /**
  29.   * @brief  system clock config program
  30.   * @note   the system clock is configured as follow:
  31.   *         - system clock        = (hext * pll_ns)/(pll_ms * pll_fr)
  32.   *         - system clock source = pll (hext)
  33.   *         - hext                = 8000000
  34.   *         - sclk                = 72000000
  35.   *         - ahbdiv              = 1
  36.   *         - ahbclk              = 72000000
  37.   *         - apb1div             = 2
  38.   *         - apb1clk             = 36000000
  39.   *         - apb2div             = 2
  40.   *         - apb2clk             = 36000000
  41.   *         - pll_ns              = 144
  42.   *         - pll_ms              = 1
  43.   *         - pll_fr              = 16
  44.   * @param  none
  45.   * @retval none
  46.   */
  47. void system_clock_config(void)
  48. {
  49.   /* enable pwc periph clock */
  50.   crm_periph_clock_enable(CRM_PWC_PERIPH_CLOCK, TRUE);
  51.  
  52.   /* config ldo voltage */
  53.   pwc_ldo_output_voltage_set(PWC_LDO_OUTPUT_1V0);
  54.  
  55.   /* set the flash clock divider */
  56.   flash_clock_divider_set(FLASH_CLOCK_DIV_2);
  57.  
  58.   /* reset crm */
  59.   crm_reset();
  60.  
  61.   /* enable hext */
  62.   crm_clock_source_enable(CRM_CLOCK_SOURCE_HEXT, TRUE);
  63.  
  64.    /* wait till hext is ready */
  65.   while(crm_hext_stable_wait() == ERROR)
  66.   {
  67.   }
  68.  
  69.   /* config pll clock resource
  70.   common frequency config list: pll source selected  hick or hext(8mhz)
  71.   _______________________________________________________________________________________
  72.   |        |         |         |         |         |         |         |        |        |
  73.   |pll(mhz)|   288   |   252   |   216   |   180   |   144   |   108   |   72   |   36   |
  74.   |________|_________|_________|_________|_________|_________|_________|_________________| 
  75.   |        |         |         |         |         |         |         |        |        |
  76.   |pll_ns  |   72    |   63    |   108   |   90    |   72    |   108   |   72   |   72   |
  77.   |        |         |         |         |         |         |         |        |        |
  78.   |pll_ms  |   1     |   1     |   1     |   1     |   1     |   1     |   1    |   1    |
  79.   |        |         |         |         |         |         |         |        |        |
  80.   |pll_fr  |   FR_2  |   FR_2  |   FR_4  |   FR_4  |   FR_4  |   FR_8  |   FR_8 |   FR_16|
  81.   |________|_________|_________|_________|_________|_________|_________|________|________|
  82.  
  83.   if pll clock source selects hext with other frequency values, or configure pll to other
  84.   frequency values, please use the at32 new clock  configuration tool for configuration.  */
  85.   crm_pll_config(CRM_PLL_SOURCE_HEXT, 144, 1, CRM_PLL_FR_16);
  86.  
  87.   /* enable pll */
  88.   crm_clock_source_enable(CRM_CLOCK_SOURCE_PLL, TRUE);
  89.  
  90.   /* wait till pll is ready */
  91.   while(crm_flag_get(CRM_PLL_STABLE_FLAG) != SET)
  92.   {
  93.   }
  94.  
  95.   /* config ahbclk */
  96.   crm_ahb_div_set(CRM_AHB_DIV_1);
  97.  
  98.   /* config apb2clk */
  99.   crm_apb2_div_set(CRM_APB2_DIV_2);
  100.  
  101.   /* config apb1clk */
  102.   crm_apb1_div_set(CRM_APB1_DIV_2);
  103.  
  104.   /* select pll as system clock source */
  105.   crm_sysclk_switch(CRM_SCLK_PLL);
  106.  
  107.   /* wait till pll is used as system clock source */
  108.   while(crm_sysclk_switch_status_get() != CRM_SCLK_PLL)
  109.   {
  110.   }
  111.  
  112.   /* update system_core_clock global variable */
  113.   system_core_clock_update();
  114. }
  115.

 osd芯片连接原理图：

 

 

接下来SPI配置：

  1. static void spi_config(void)
  2. {
  3.   spi_init_type spi_init_struct;
  4.   crm_periph_clock_enable(CRM_SPI2_PERIPH_CLOCK, TRUE);
  5.   spi_default_para_init(&spi_init_struct);
  6.   spi_init_struct.transmission_mode = SPI_TRANSMIT_FULL_DUPLEX;
  7.   spi_init_struct.master_slave_mode = SPI_MODE_MASTER;
  8.   spi_init_struct.mclk_freq_division = SPI_MCLK_DIV_8;
  9.   spi_init_struct.first_bit_transmission = SPI_FIRST_BIT_MSB;
  10.   spi_init_struct.frame_bit_num = SPI_FRAME_8BIT;
  11.   spi_init_struct.clock_polarity = SPI_CLOCK_POLARITY_LOW;
  12.   spi_init_struct.clock_phase = SPI_CLOCK_PHASE_1EDGE;
  13.   spi_init_struct.cs_mode_selection = SPI_CS_SOFTWARE_MODE;
  14.   spi_init(SPI2, &spi_init_struct);
  15.   spi_enable(SPI2, TRUE);
  16. }
  17.  
  18. /**
  19.   * @brief  gpio configuration.
  20.   * @param  none
  21.   * @retval none
  22.   */
  23. static void gpio_config(void)
  24. {
  25.   gpio_init_type gpio_initstructure;
  26.   crm_periph_clock_enable(CRM_GPIOD_PERIPH_CLOCK, TRUE);
  27.  
  28.   /* master sck pin */
  29.   gpio_initstructure.gpio_out_type       = GPIO_OUTPUT_PUSH_PULL;
  30.   gpio_initstructure.gpio_pull           = GPIO_PULL_DOWN;
  31.   gpio_initstructure.gpio_mode           = GPIO_MODE_MUX;
  32.   gpio_initstructure.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER;
  33.   gpio_initstructure.gpio_pins           = GPIO_PINS_1;
  34.   gpio_init(GPIOD, &gpio_initstructure);
  35.   gpio_pin_mux_config(GPIOD, GPIO_PINS_SOURCE1, GPIO_MUX_6);
  36.  
  37.   /* spi2 miso pin */
  38.   gpio_initstructure.gpio_pull           = GPIO_PULL_UP;
  39.   gpio_initstructure.gpio_pins           = GPIO_PINS_3;
  40.   gpio_init(GPIOD, &gpio_initstructure);
  41.   gpio_pin_mux_config(GPIOD, GPIO_PINS_SOURCE3, GPIO_MUX_6);
  42.  
  43.   /* spi2 mosi pin */
  44.   gpio_initstructure.gpio_pull           = GPIO_PULL_UP;
  45.   gpio_initstructure.gpio_pins           = GPIO_PINS_4;
  46.   gpio_init(GPIOD, &gpio_initstructure);
  47.   gpio_pin_mux_config(GPIOD, GPIO_PINS_SOURCE4, GPIO_MUX_6);
  48.  
  49.   gpio_initstructure.gpio_mode = GPIO_MODE_OUTPUT;
  50.   gpio_initstructure.gpio_pins = GPIO_PINS_5;
  51.   gpio_initstructure.gpio_pull = GPIO_PULL_NONE;
  52.   gpio_init(GPIOD, &gpio_initstructure);
  53.  
  54.   gpio_bits_write(GPIOD, GPIO_PINS_5, 0);
  55.  
  56. }

主要注意下面的点 

 SPI收发函数，因为是全双工模式，所以这里发送和接收在一个函数中。具体可以看上一篇文章说明了为什么要一起做。

  1. /*************************************************************
  2. ** Function name:       SPI2SendAndReceviceOneByte
  3. ** Descriptions:        使用全双工模式的spi进行发送同时接收一字节数据
  4. ** Input parameters:    None
  5. ** Output parameters:   None
  6. ** Returned value:      None
  7. ** Remarks:             None
  8. *************************************************************/
  9. uint8_t SPI2SendAndReceviceOneByte(uint8_t data){
  10.     while(spi_i2s_flag_get(SPI2, SPI_I2S_TDBE_FLAG) == RESET);
  11.     spi_i2s_data_transmit(SPI2, MAX7456ADD_STAT);
  12.     while(spi_i2s_flag_get(SPI2, SPI_I2S_RDBF_FLAG) == RESET);
  13.     return (uint8_t)spi_i2s_data_receive(SPI2);
  14. }

我之前是分开写的，像是下面的样子：发送了两次，接收一次。这样是错误的

 因为第一次是发送数据，所以没接收。但是发现程序只能成功接收一次。

原因:每次发送的同时都会接收数据，如果这次发送完成后，没有将数据读出来。之后的数据就不会覆盖没读出来的数据，导致往后接收失败。

正确写法：

  1. int main(void)
  2. {
  3.   uint16_t redata = 0;
  4.   system_clock_config();
  5.   at32_board_init();
  6.   gpio_config();
  7.   spi_config();
  8.  
  9.   delay_ms(200);
  10.   SEGGER_RTT_printf(0,"Init ok \r\n");
  11.  
  12.   while(1)
  13.   {
  14.     SPI2SendAndReceviceOneByte(MAX7456ADD_STAT);
  15.     redata = SPI2SendAndReceviceOneByte(0xff);
  16.  
  17.     delay_ms(200);
  18.     if (redata != 0){
  19.       SEGGER_RTT_printf(0,"%d   %x\r\n",redata,redata);
  20.     }
  21.     // delay_us(2);
  22.   }
  23. }

贴个实际的spi信号

 

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