应用实例2
实例：stm32f412+ADS1256（8通道带PGA的24位ADC）
ADS1256精度很高，适合做5位半万用表，称重系统。
1 程序分析：
1.1 主程序
int main(void)
{
int32_tadc[8];
int32_tvolt[8];
uint8_ti;
bsp_Init();
PrintfLogo(); /* 串口输出 */
bsp_DelayMS(100); /* 延时 */
bsp_InitADS1256();
/*初始化ADS1256. PGA=1, DRATE=30KSPS,BUFEN=1,输入电压正负5V */
{
uint8_tid;
id= ADS1256_ReadChipID(); //读取芯片id
if(id ！= 3)
{
printf("Error,ASD1256 Chip ID = 0x%X\r\n", id);
}
else
{
printf("Ok,ASD1256 Chip ID = 0x%X\r\n", id);
}
}
ADS1256_CfgADC(ADS1256_GAIN_1,ADS1256_1000SPS);
/*配置adc参数，增益1：1 输出速率 1KHz */
ADS1256_StartScan(); /* 启动中断扫描模式，轮流采集8通道数据 */
while(1)
{
bsp_Idle(); /* 空闲函数，看门狗*/
for(i = 0; i < 8; i++)
{
/*采样结果*/
adc= ADS1256_GetAdc(i);
/*4194303对应2.5V */
volt= ((int64_t)adc * 2500000) / 4194303; /*计算实际电压 */
}
{
int32_tiTemp;
for(i = 0; i < 8; i++)
{
iTemp= volt;
if(iTemp < 0)
{
iTemp= -iTemp;
printf("%d=%6d,(-%d.%03d%03d V) ", i, adc, iTemp /1000000, (iTemp%1000000)/1000, iTemp%1000);
}
else
{
printf("%d=%6d,(%d.%03d %03d V) ", i, adc, iTemp/1000000, (iTemp%1000000)/1000,iTemp%1000);
}
}
printf("\r\n");
}
bsp_DelayMS(300); /*延时 */
}
}
1.2配置系统时钟
#if defined (STM32F40_41xxx)
uint32_t SystemCoreClock = 100000000;
#endif /* STM32F40_41xxx */
SystemInit() 该函数被启动文件调用。
void SystemInit(void)
{
/*FPU settings ------------------------------------------------------------*/
#if(__FPU_PRESENT == 1) && (__FPU_USED == 1)
SCB->CPACR |= ((3UL << 10*2)|(3UL << 11*2)); /* set CP10 and CP11 Full Access */
#endif
/*Reset the RCC clock configuration to the default reset state ------------*/
/*Set HSION bit */
RCC->CR |= (uint32_t)0x00000001;
/*Reset CFGR register */
RCC->CFGR = 0x00000000;
/*Reset HSEON, CSSON and PLLON bits */
RCC->CR &= (uint32_t)0xFEF6FFFF;
/*Reset PLLCFGR register */
RCC->PLLCFGR = 0x24003010;
/*Reset HSEBYP bit */
RCC->CR &= (uint32_t)0xFFFBFFFF;
/*Disable all interrupts */
RCC->CIR = 0x00000000;
#if defined (DATA_IN_ExtSRAM) || defined(DATA_IN_ExtSDRAM)
SystemInit_ExtMemCtl();
#endif /* DATA_IN_ExtSRAM ||DATA_IN_ExtSDRAM */
/*Configure the System clock source, PLL Multiplier and Divider factors,
AHB/APBx prescalers and Flash settings----------------------------------*/
SetSysClock();
/*Configure the Vector Table location add offset address ------------------*/
#ifdef VECT_TAB_SRAM
SCB->VTOR = SRAM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocationin Internal SRAM */
#else
SCB->VTOR = FLASH_BASE | VECT_TAB_OFFSET; /* Vector Table Relocationin Internal FLASH */
#endif
}
1.3 硬件配置
void SystemInit_ExtMemCtl(void)
{
register uint32_t tmpreg = 0, timeout = 0xFFFF;
register uint32_t index;
/*Enable GPIOC, GPIOD, GPIOE, GPIOF, GPIOG, GPIOH and GPIOI interface
clock */
RCC->AHB1ENR |= 0x000001FC;
/*Connect PCx pins to FMC Alternate function */
GPIOC->AFR[0] = 0x0000000c;
GPIOC->AFR[1] = 0x00007700;
/*Configure PCx pins in Alternate function mode */
GPIOC->MODER = 0x00a00002;
/*Configure PCx pins speed to 50 MHz */
GPIOC->OSPEEDR = 0x00a00002;
/*Configure PCx pins Output type to push-pull */
GPIOC->OTYPER = 0x00000000;
/*No pull-up, pull-down for PCx pins */
GPIOC->PUPDR = 0x00500000;
/*Connect PDx pins to FMC Alternate function */
GPIOD->AFR[0] = 0x000000CC;
GPIOD->AFR[1] = 0xCC000CCC;
/*Configure PDx pins in Alternate function mode */
GPIOD->MODER = 0xA02A000A;
/*Configure PDx pins speed to 50 MHz */
GPIOD->OSPEEDR = 0xA02A000A;
/*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 50 MHz */
GPIOE->OSPEEDR = 0xAAAA800A;
/*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] = 0xcccccccc;
GPIOF->AFR[1] = 0xcccccccc;
/*Configure PFx pins in Alternate function mode */
GPIOF->MODER = 0xAA800AAA;
/*Configure PFx pins speed to 50 MHz */
GPIOF->OSPEEDR = 0xAA800AAA;
/*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] = 0xcccccccc;
GPIOG->AFR[1] = 0xcccccccc;
/* ConfigurePGx pins in Alternate function mode */
GPIOG->MODER = 0xaaaaaaaa;
/*Configure PGx pins speed to 50 MHz */
GPIOG->OSPEEDR = 0xaaaaaaaa;
/*Configure PGx pins Output type to push-pull */
GPIOG->OTYPER = 0x00000000;
/*No pull-up, pull-down for PGx pins */
GPIOG->PUPDR = 0x00000000;
/*Connect PHx pins to FMC Alternate function */
GPIOH->AFR[0] = 0x00C0CC00;
GPIOH->AFR[1] = 0xCCCCCCCC;
/*Configure PHx pins in Alternate function mode */
GPIOH->MODER = 0xAAAA08A0;
/*Configure PHx pins speed to 50 MHz */
GPIOH->OSPEEDR = 0xAAAA08A0;
/*Configure PHx pins Output type to push-pull */
GPIOH->OTYPER = 0x00000000;
/*No pull-up, pull-down for PHx pins */
GPIOH->PUPDR = 0x00000000;
/*Connect PIx pins to FMC Alternate function */
GPIOI->AFR[0] = 0xCCCCCCCC;
GPIOI->AFR[1] = 0x00000CC0;
/*Configure PIx pins in Alternate function mode */
GPIOI->MODER = 0x0028AAAA;
/*Configure PIx pins speed to 50 MHz */
GPIOI->OSPEEDR = 0x0028AAAA;
/*Configure PIx pins Output type to push-pull */
GPIOI->OTYPER = 0x00000000;
/*No pull-up, pull-down for PIx pins */
GPIOI->PUPDR = 0x00000000;
/*-- FMC Configuration------------------------------------------------------*/
/*Enable the FMC interface clock */
RCC->AHB3ENR |= 0x00000001;
/*Configure and enable SDRAM bank1 */
FMC_Bank5_6->SDCR[0] = 0x000039D0;
FMC_Bank5_6->SDTR[0] = 0x01115351;
/*SDRAM initialization sequence */
/*Clock enable command */
FMC_Bank5_6->SDCMR = 0x00000011;
tmpreg = FMC_Bank5_6->SDSR & 0x00000020;
while((tmpreg ！= 0) & (timeout-- > 0))
{
tmpreg = FMC_Bank5_6->SDSR & 0x00000020;
}
/*Delay */
for(index = 0; index<1000; index++);
/*PALL command */
FMC_Bank5_6->SDCMR = 0x00000012;
timeout = 0xFFFF;
while((tmpreg ！= 0) & (timeout-- > 0))
{
tmpreg = FMC_Bank5_6->SDSR & 0x00000020;
}
/*Auto refresh command */
FMC_Bank5_6->SDCMR = 0x00000073;
timeout = 0xFFFF;
while((tmpreg！= 0) & (timeout-- > 0))
{
tmpreg = FMC_Bank5_6->SDSR & 0x00000020;
}
/*MRD register program */
FMC_Bank5_6->SDCMR = 0x00046014;
timeout = 0xFFFF;
while((tmpreg ！= 0) & (timeout-- > 0))
{
tmpreg = FMC_Bank5_6->SDSR & 0x00000020;
}
/*Set refresh count */
tmpreg = FMC_Bank5_6->SDRTR;
FMC_Bank5_6->SDRTR = (tmpreg | (0x0000027C<<1));
/*Disable write protection */
tmpreg = FMC_Bank5_6->SDCR[0];
FMC_Bank5_6->SDCR[0] = (tmpreg & 0xFFFFFDFF);
}
快来看看啊