Difference between revisions of "STM32 Bit Banding (or bit-banding)"
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[[Category:STM32]][[Category:STM32 Development]][[Category:C]]{{metadesc|Bit Banding in STM32 MCUs}} | [[Category:STM32]][[Category:STM32 Development]][[Category:C]]{{metadesc|Bit Banding in STM32 MCUs}} | ||
In older 8-bit [[MCU]]s it was quite common to have instructions to clear or set a bit as one atomic instruction. By atomic it means the read->modify->write can not be interrupted resulting in other bits being set wrongly. | In older 8-bit [[MCU]]s it was quite common to have instructions to clear or set a bit as one atomic instruction. By atomic it means the read->modify->write can not be interrupted resulting in other bits being set wrongly. | ||
| + | |||
| + | == Macro's to Calculate Bit Band Address == | ||
| + | |||
| + | <pre> | ||
| + | #define BITBAND_SRAM_REF 0x20000000 | ||
| + | #define BITBAND_SRAM_BASE 0x22000000 | ||
| + | #define BITBAND_PERIPH_REF 0x40000000 | ||
| + | #define BITBAND_PERIPH_BASE 0x42000000 | ||
| + | |||
| + | #define bitband_t *(volatile uint32_t*) | ||
| + | |||
| + | #define m_BITBAND_SRAM(address,bit) (BITBAND_SRAM_BASE + (((uint32_t)address) - BITBAND_SRAM_REF) * 32 + (bit) * 4) | ||
| + | #define m_BITBAND_PERIPH(address,bit) (BITBAND_PERIPH_BASE + (((uint32_t)address) - BITBAND_PERIPH_REF) * 32 + (bit) * 4) | ||
| + | </pre> | ||
== Miscellaneous Links == | == Miscellaneous Links == | ||
To be added | To be added | ||
Revision as of 05:49, 20 October 2024
In older 8-bit MCUs it was quite common to have instructions to clear or set a bit as one atomic instruction. By atomic it means the read->modify->write can not be interrupted resulting in other bits being set wrongly.
Macro's to Calculate Bit Band Address
#define BITBAND_SRAM_REF 0x20000000 #define BITBAND_SRAM_BASE 0x22000000 #define BITBAND_PERIPH_REF 0x40000000 #define BITBAND_PERIPH_BASE 0x42000000 #define bitband_t *(volatile uint32_t*) #define m_BITBAND_SRAM(address,bit) (BITBAND_SRAM_BASE + (((uint32_t)address) - BITBAND_SRAM_REF) * 32 + (bit) * 4) #define m_BITBAND_PERIPH(address,bit) (BITBAND_PERIPH_BASE + (((uint32_t)address) - BITBAND_PERIPH_REF) * 32 + (bit) * 4)
Miscellaneous Links
To be added