ardupilot/libraries/AP_HAL_AVR/SPIDevice_SPI2.cpp

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#include <AP_HAL.h>
#if (CONFIG_HAL_BOARD == HAL_BOARD_APM1 || CONFIG_HAL_BOARD == HAL_BOARD_APM2)
#include <avr/io.h>
#include <AP_HAL.h>
#include "SPIDevices.h"
#include "GPIO.h"
#include "Semaphores.h"
#include "pins_arduino_mega.h"
using namespace AP_HAL_AVR;
extern const AP_HAL::HAL& hal;
AVRSemaphore AVRSPI2DeviceDriver::_semaphore;
void AVRSPI2DeviceDriver::init() {
AVRDigitalSource spi2_miso(_BV(0), PH);
spi2_miso.mode(GPIO_INPUT);
AVRDigitalSource spi2_mosi(_BV(1), PH);
spi2_mosi.mode(GPIO_OUTPUT);
AVRDigitalSource spi2_sck(_BV(2), PH);
spi2_sck.mode(GPIO_OUTPUT);
/* UMSELn1 and UMSELn2: USART in SPI Master mode */
UCSR2C = _BV(UMSEL21) | _BV(UMSEL20);
/* Enable RX and TX. */
UCSR2B = _BV(RXEN2) | _BV(TXEN2);
/* Setup chip select pin */
_cs_pin->mode(GPIO_OUTPUT);
_cs_pin->write(1);
}
AP_HAL::Semaphore* AVRSPI2DeviceDriver::get_semaphore() {
return &_semaphore;
}
inline void AVRSPI2DeviceDriver::_cs_assert() {
/* set the device UCSRnC configuration bits.
* only sets data order, clock phase, and clock polarity bits (lowest
* three bits) */
const uint8_t new_ucsr2c = UCSR2C | (_ucsr2c & (0x07));
UCSR2C = new_ucsr2c;
/* set the device baud rate */
UBRR2 = _ubrr2;
_cs_pin->write(0);
}
inline void AVRSPI2DeviceDriver::_cs_release() {
_cs_pin->write(1);
}
inline uint8_t AVRSPI2DeviceDriver::_transfer(uint8_t data) {
/* Wait for empty transmit buffer */
while ( !( UCSR2A & _BV(UDRE2)) ) ;
/* Put data into buffer, sends the data */
UDR2 = data;
/* Wait for data to be received */
while ( !(UCSR2A & _BV(RXC2)) ) ;
/* Get and return received data from buffer */
return UDR2;
}
void AVRSPI2DeviceDriver::transaction(const uint8_t *tx, uint8_t *rx,
uint16_t len) {
_cs_assert();
if (rx == NULL) {
for (uint16_t i = 0; i < len; i++) {
_transfer(tx[i]);
}
} else {
for (uint16_t i = 0; i < len; i++) {
rx[i] = _transfer(tx[i]);
}
}
_cs_release();
}
void AVRSPI2DeviceDriver::cs_assert() {
_cs_assert();
}
void AVRSPI2DeviceDriver::cs_release() {
_cs_release();
}
uint8_t AVRSPI2DeviceDriver::transfer(uint8_t data) {
return _transfer(data);
}
#endif