怎样处理才能使GPIO的操作速度最快

只看该作者 · 2014-10-22 18:21

请教各位大虾，怎样才能提高GPIO的操作速度？
芯片选用的是:STM32F072C8

原来的程序如下：

#define HC595_DATA_HI GPIOB->BSRR |= (1<<HC595_DATA)
#define HC595_DATA_LO GPIOB->BRR  |= (1<<HC595_DATA)

#define HC595_CLK_HI          GPIOB->BSRR |= (1<<HC595_CLK)
#define HC595_CLK_LO GPIOB->BRR  |= (1<<HC595_CLK)

void Handle74HC595(uint8_t tTmp)
{
uint8_t tCnt;
for(tCnt = 0; tCnt<8; tCnt++)
{
if(tTmp&0x01)
{
HC595_DATA_HI;
__nop();
}
else
{
HC595_DATA_LO;
__nop();
}
__nop();
HC595_CLK_LO;
__nop();
HC595_CLK_HI;
tTmp >>= 1;
}
}

以下是我新改的:
void Handle74HC595(register uint8_t tTmp)
{
if(tTmp&0x01)
{
HC595_DATA_HI; __nop();
}
else
{
HC595_DATA_LO; __nop();
}
HC595_CLK_LO; __nop();
HC595_CLK_HI; __nop();

if(tTmp&0x02)
{
HC595_DATA_HI; __nop();
}
else
{
HC595_DATA_LO; __nop();
}
HC595_CLK_LO; __nop();
HC595_CLK_HI; __nop();

if(tTmp&0x04)
{
HC595_DATA_HI; __nop();
}
else
{
HC595_DATA_LO; __nop();
}
HC595_CLK_LO; __nop();
HC595_CLK_HI; __nop();

if(tTmp&0x08)
{
HC595_DATA_HI; __nop();
}
else
{
HC595_DATA_LO; __nop();
}
HC595_CLK_LO; __nop();
HC595_CLK_HI; __nop();

if(tTmp&0x10)
{
HC595_DATA_HI; __nop();
}
else
{
HC595_DATA_LO; __nop();
}
HC595_CLK_LO; __nop();
HC595_CLK_HI; __nop();

if(tTmp&0x20)
{
HC595_DATA_HI; __nop();
}
else
{
HC595_DATA_LO; __nop();
}
HC595_CLK_LO; __nop();
HC595_CLK_HI; __nop();

if(tTmp&0x40)
{
HC595_DATA_HI; __nop();
}
else
{
HC595_DATA_LO; __nop();
}
HC595_CLK_LO; __nop();
HC595_CLK_HI; __nop();

if(tTmp&0x80)
{
HC595_DATA_HI; __nop();
}
else
{
HC595_DATA_LO; __nop();
}
HC595_CLK_LO; __nop();
HC595_CLK_HI; __nop();
}

谢谢！

3万 · 2014-10-22 19:08

define             HC595_DATA_HI             GPIOB->BSRR |= (1<<HC595_DATA)
#define             HC595_DATA_LO             GPIOB->BRR  |= (1<<HC595_DATA)

#define             HC595_CLK_HI                      GPIOB->BSRR |= (1<<HC595_CLK)
#define             HC595_CLK_LO             GPIOB->BRR  |= (1<<HC595_CLK)
这几句可以再优化下；
每次操作，都要移位，也要时间的；