Kinetis Bit Manipulation Engine (BME)

Macros for using decorated memory accesses with the Bit Manipulation Engine available in Kinetis Cortex-M0+ devices.

void * bme_bf_addr(volatile void * ptr, uintptr_t bit, uintptr_t width)

Bit field address macro.

Parameters

ptr:Pointer to target register
bit:Location of the LSB of the bitfield within the register
width:Width of the the bitfield, in bits

Return values

  • bitfield address as an uintptr_t
uint32_t * bme_bitfield32(volatile uint32_t * ptr, uint8_t bit, uint8_t width)

Access a bitfield (32 bit load/store)

This macro can be used both for store (*bme_bitfield32(xxx) = y) and load (y = *bme_bitfield32(ptr, bit))

Parameters

ptr:Pointer to target register
bit:Location of the LSB of the bitfield within the register
width:Width of the the bitfield, in bits

Return values

  • bitfield extracted as a (modifiable) lvalue
uint16_t * bme_bitfield16(volatile uint16_t * ptr, uint8_t bit, uint8_t width)

Access a bitfield (16 bit load/store)

This macro can be used both for store (*bme_bitfield16(xxx) = y) and load (y = *bme_bitfield16(ptr, bit))

Parameters

ptr:Pointer to target register
bit:Location of the LSB of the bitfield within the register
width:Width of the the bitfield, in bits

Return values

  • bitfield extracted as a (modifiable) lvalue
uint8_t * bme_bitfield8(volatile uint8_t * ptr, uint8_t bit, uint8_t width)

Access a bitfield (8 bit load/store)

This macro can be used both for store (*bme_bitfield8(xxx) = y) and load (y = *bme_bitfield8(ptr, bit))

Parameters

ptr:Pointer to target register
bit:Location of the LSB of the bitfield within the register
width:Width of the the bitfield, in bits

Return values

  • bitfield extracted as a (modifiable) lvalue
void bit_set32(volatile uint32_t * ptr, uint8_t bit)

Set a single bit in the 32 bit word pointed to by ptr.

The effect is the same as for the following snippet:

1
*ptr |= (1 << bit);

There is a read-modify-write cycle occurring within the core, but this cycle is atomic and can not be disrupted by IRQs

Parameters

ptr:pointer to target word
bit:bit number within the word

void bit_set16(volatile uint16_t * ptr, uint8_t bit)

Set a single bit in the 16 bit word pointed to by ptr.

The effect is the same as for the following snippet:

1
*ptr |= (1 << bit);

There is a read-modify-write cycle occurring within the core, but this cycle is atomic and can not be disrupted by IRQs

Parameters

ptr:pointer to target word
bit:bit number within the word

void bit_set8(volatile uint8_t * ptr, uint8_t bit)

Set a single bit in the 8 bit byte pointed to by ptr.

The effect is the same as for the following snippet:

1
*ptr |= (1 << bit);

There is a read-modify-write cycle occurring within the core, but this cycle is atomic and can not be disrupted by IRQs

Parameters

ptr:pointer to target byte
bit:bit number within the byte

void bit_clear32(volatile uint32_t * ptr, uint8_t bit)

Clear a single bit in the 32 bit word pointed to by ptr.

The effect is the same as for the following snippet:

1
*ptr &= ~(1 << bit);

There is a read-modify-write cycle occurring within the core, but this cycle is atomic and can not be disrupted by IRQs

Parameters

ptr:pointer to target word
bit:bit number within the word

void bit_clear16(volatile uint16_t * ptr, uint8_t bit)

Clear a single bit in the 16 bit word pointed to by ptr.

The effect is the same as for the following snippet:

1
*ptr &= ~(1 << bit);

There is a read-modify-write cycle occurring within the core, but this cycle is atomic and can not be disrupted by IRQs

Parameters

ptr:pointer to target word
bit:bit number within the word

void bit_clear8(volatile uint8_t * ptr, uint8_t bit)

Clear a single bit in the 8 bit byte pointed to by ptr.

The effect is the same as for the following snippet:

1
*ptr &= ~(1 << bit);

There is a read-modify-write cycle occurring within the core, but this cycle is atomic and can not be disrupted by IRQs

Parameters

ptr:pointer to target byte
bit:bit number within the byte

BITBAND_FUNCTIONS_PROVIDED

Tell bit.h that we provide CPU specific bit manipulation functions. 

1
1
BME_AND_MASK

AND decoration bitmask. 

1
(1 << 26)
BME_OR_MASK

OR decoration bitmask. 

1
(1 << 27)
BME_XOR_MASK

XOR decoration bitmask. 

1
(3 << 26)
BME_LAC1_MASK( BIT)

Load-and-clear 1 bit. 

1
((1 << 27) | ((BIT) << 21))
BME_LAS1_MASK( BIT)

Load-and-set 1 bit. 

1
((3 << 26) | ((BIT) << 21))
BME_BF_MASK( bit, width)

Bit field extraction bitmask. 

1
((1 << 28) | ((bit) << 23) | (((width) - 1 ) << 19))

Parameters

bit:LSB of the bitfield within the word/halfword/byte
width:Number of bits to extract