Can I read status of a GPIO input pin using bit banding?

Posted on May 17, 2011 at 13:25

#define PERIPH_BB_BASE ((uint32_t)0x42000000)

#define PERIPH_BASE ((uint32_t)0x40000000)

#define APB1PERIPH_BASE PERIPH_BASE

#define APB2PERIPH_BASE (PERIPH_BASE + 0x10000)

#define AHBPERIPH_BASE (PERIPH_BASE + 0x20000)

#define GPIOA_BASE (APB2PERIPH_BASE + 0x0800)

#define GPIOB_BASE (APB2PERIPH_BASE + 0x0C00)

#define GPIOC_BASE (APB2PERIPH_BASE + 0x1000)

#define GPIOD_BASE (APB2PERIPH_BASE + 0x1400)

#define GPIOE_BASE (APB2PERIPH_BASE + 0x1800)

#define GPIOF_BASE (APB2PERIPH_BASE + 0x1C00)

#define GPIOG_BASE (APB2PERIPH_BASE + 0x2000)

#define GPIO_IDR_OFF (0x08) // Input Data register offset

// For example GPIO PA.05

#define GPIO_BASE GPIOA_BASE

#define GPIO_BIT 5

u32 *BitBandAddr;

BitBandAddr = (u32 *)(PERIPH_BB_BASE + (((GPIO_BASE - PERIPH_BASE) + GPIO_IDR_OFF) * 32) + (GPIO_BIT * 4));

if (*BitBandAddr)

puts(''Bit High'');

else

puts(''Bit Low'');

The address of PA.05 should be 0x42210114 if my math is correct.

-Clive

Posted on May 17, 2011 at 13:25

Can I use bit banding to read the status of a GPIO input pin?

If so, how?