下一步就是修改寄存器的配置,SystemInit_ExtMemCtl函数407部分FSMC的配置默认是NE2的。找到407部分(有2部分,一部分为引脚配置,一部分为FSMC配置,找到有defined(STM32F407xx)字样的代码部分就是)将寄存器配置修改为以下内容
- #if defined(STM32F405xx) || defined(STM32F415xx) || defined(STM32F407xx) || defined(STM32F417xx)\
- || defined(STM32F427xx) || defined(STM32F437xx) || defined(STM32F429xx) || defined(STM32F439xx)\
- || defined(STM32F469xx) || defined(STM32F479xx) || defined(STM32F412Zx) || defined(STM32F412Vx)
-
- #if defined(DATA_IN_ExtSRAM)
- /*-- GPIOs Configuration -----------------------------------------------------*/
- /* Enable GPIOD, GPIOE, GPIOF and GPIOG interface clock */
- RCC->AHB1ENR |= 0x00000078;
- /* Delay after an RCC peripheral clock enabling */
- tmp = READ_BIT(RCC->AHB1ENR, RCC_AHB1ENR_GPIODEN);
-
- /* Connect PDx pins to FMC Alternate function */
- GPIOD->AFR[0] = 0x00CC00CC;
- GPIOD->AFR[1] = 0xCCCCCCCC;
- /* Configure PDx pins in Alternate function mode */
- GPIOD->MODER = 0xAAAA0A0A;
- /* Configure PDx pins speed to 100 MHz */
- GPIOD->OSPEEDR = 0xFFFF0F0F;
- /* Configure PDx pins Output type to push-pull */
- GPIOD->OTYPER = 0x00000000;
- /* No pull-up, pull-down for PDx pins */
- GPIOD->PUPDR = 0x00000000;
-
- /* Connect PEx pins to FMC Alternate function */
- GPIOE->AFR[0] = 0xC00000CC;
- GPIOE->AFR[1] = 0xCCCCCCCC;
- /* Configure PEx pins in Alternate function mode */
- GPIOE->MODER = 0xAAAA800A;
- /* Configure PEx pins speed to 100 MHz */
- GPIOE->OSPEEDR = 0xFFFFC00F;
- /* Configure PEx pins Output type to push-pull */
- GPIOE->OTYPER = 0x00000000;
- /* No pull-up, pull-down for PEx pins */
- GPIOE->PUPDR = 0x00000000;
-
- /* Connect PFx pins to FMC Alternate function */
- GPIOF->AFR[0] = 0x00CCCCCC;
- GPIOF->AFR[1] = 0xCCCC0000;
- /* Configure PFx pins in Alternate function mode */
- GPIOF->MODER = 0xAA000AAA;
- /* Configure PFx pins speed to 100 MHz */
- GPIOF->OSPEEDR = 0xFF000FFF;
- /* Configure PFx pins Output type to push-pull */
- GPIOF->OTYPER = 0x00000000;
- /* No pull-up, pull-down for PFx pins */
- GPIOF->PUPDR = 0x00000000;
-
- /* Connect PGx pins to FMC Alternate function */
- GPIOG->AFR[0] = 0x00CCCCCC;
- GPIOG->AFR[1] = 0x00000C00;
- /* Configure PGx pins in Alternate function mode */
- GPIOG->MODER = 0x00200AAA;
- /* Configure PGx pins speed to 100 MHz */
- GPIOG->OSPEEDR = 0x000C03FF;
- /* Configure PGx pins Output type to push-pull */
- GPIOG->OTYPER = 0x00000000;
- /* No pull-up, pull-down for PGx pins */
- GPIOG->PUPDR = 0x00000000;
-
- /*-- FMC/FSMC Configuration --------------------------------------------------*/
- /* Enable the FMC/FSMC interface clock */
- RCC->AHB3ENR |= 0x00000001;
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