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HAL_AVR: added specialised transfer functions for MPU6k and APM1 ADC 

this saves quite a lot of time in interrupts
This commit is contained in:
Andrew Tridgell 2013-10-10 21:13:24 +11:00 committed by Randy Mackay
parent 64d34dc125
commit 5ba34b38c1
3 changed files with 70 additions and 0 deletions
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32
libraries/AP_HAL_AVR/SPIDevice_SPI0.cpp
View File

@ -69,6 +69,32 @@ inline uint8_t AVRSPI0DeviceDriver::_transfer(uint8_t data) {
return read_spdr;
}
/**
a specialised transfer function for the MPU6k. This saves 2 usec
per byte
*/
void AVRSPI0DeviceDriver::_transfer15(const uint8_t *tx, uint8_t *rx)
{
spi0_transferflag = true;
#define TRANSFER1(i) do { SPDR = tx[i]; while(!(SPSR & _BV(SPIF))); rx[i] = SPDR; } while(0)
TRANSFER1(0);
TRANSFER1(1);
TRANSFER1(2);
TRANSFER1(3);
TRANSFER1(4);
TRANSFER1(5);
TRANSFER1(6);
TRANSFER1(7);
TRANSFER1(8);
TRANSFER1(9);
TRANSFER1(10);
TRANSFER1(11);
TRANSFER1(12);
TRANSFER1(13);
TRANSFER1(14);
spi0_transferflag = false;
}
void AVRSPI0DeviceDriver::transfer(const uint8_t *tx, uint16_t len) {
for (uint16_t i = 0; i < len; i++) {
_transfer(tx[i]);
@ -83,6 +109,12 @@ void AVRSPI0DeviceDriver::transaction(const uint8_t *tx, uint8_t *rx,
_transfer(tx[i]);
}
} else {
while (len >= 15) {
_transfer15(tx, rx);
tx += 15;
rx += 15;
len -= 15;
}
for (uint16_t i = 0; i < len; i++) {
rx[i] = _transfer(tx[i]);
}

34
libraries/AP_HAL_AVR/SPIDevice_SPI2.cpp
View File

@ -69,6 +69,34 @@ inline uint8_t AVRSPI2DeviceDriver::_transfer(uint8_t data) {
return UDR2;
}
/**
a specialist transfer function for the APM1 ADC
*/
void AVRSPI2DeviceDriver::_transfer17(const uint8_t *tx, uint8_t *rx)
{
#define TRANSFER1(i) do { while ( !( UCSR2A & _BV(UDRE2)) ); \
UDR2 = tx[i]; \
while ( !(UCSR2A & _BV(RXC2)) ) ; \
rx[i] = UDR2; } while (0)
TRANSFER1(0);
TRANSFER1(1);
TRANSFER1(2);
TRANSFER1(3);
TRANSFER1(4);
TRANSFER1(5);
TRANSFER1(6);
TRANSFER1(7);
TRANSFER1(8);
TRANSFER1(9);
TRANSFER1(10);
TRANSFER1(11);
TRANSFER1(12);
TRANSFER1(13);
TRANSFER1(14);
TRANSFER1(15);
TRANSFER1(16);
}
void AVRSPI2DeviceDriver::transaction(const uint8_t *tx, uint8_t *rx,
uint16_t len) {
_cs_assert();
@ -77,6 +105,12 @@ void AVRSPI2DeviceDriver::transaction(const uint8_t *tx, uint8_t *rx,
_transfer(tx[i]);
}
} else {
while (len >= 17) {
_transfer17(tx, rx);
tx += 17;
rx += 17;
len -= 17;
}
for (uint16_t i = 0; i < len; i++) {
rx[i] = _transfer(tx[i]);
}

4
libraries/AP_HAL_AVR/SPIDevices.h
View File

@ -31,6 +31,8 @@ private:
void _cs_assert();
void _cs_release();
uint8_t _transfer(uint8_t data);
// used for MPU6k
void _transfer15(const uint8_t *tx, uint8_t *rx);
static AP_HAL_AVR::AVRSemaphore _semaphore;
@ -66,6 +68,8 @@ private:
void _cs_assert();
void _cs_release();
uint8_t _transfer(uint8_t data);
// used for APM1 ADC
void _transfer17(const uint8_t *tx, uint8_t *rx);
static AP_HAL_AVR::AVRSemaphore _semaphore;