ardupilot/libraries/AP_HAL_AVR/SPIDevice_SPI3.cpp

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/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
#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"
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#include "Semaphores.h"
#include "utility/pins_arduino_mega.h"
using namespace AP_HAL_AVR;
#define SPI3_MOSI 14
#define SPI3_MISO 15
extern const AP_HAL::HAL& hal;
AVRSemaphore AVRSPI3DeviceDriver::_semaphore;
void AVRSPI3DeviceDriver::init() {
/* the spi3 (USART3) sck pin PORTJ2 is not enumerated
* by the arduino pin numbers, so we access it directly
* with AVRDigitalSource. */
AVRDigitalSource spi3_sck(_BV(2), PJ);
spi3_sck.mode(GPIO_OUTPUT);
hal.gpio->pinMode(SPI3_MOSI, GPIO_OUTPUT);
hal.gpio->pinMode(SPI3_MISO, GPIO_INPUT);
/* UMSELn1 and UMSELn2: USART in SPI Master mode */
UCSR3C = _BV(UMSEL31) | _BV(UMSEL30);
/* Enable RX and TX. */
UCSR3B = _BV(RXEN3) | _BV(TXEN3);
/* Setup chip select pin */
_cs_pin->mode(GPIO_OUTPUT);
_cs_pin->write(1);
}
AP_HAL::Semaphore* AVRSPI3DeviceDriver::get_semaphore() {
return &_semaphore;
}
void AVRSPI3DeviceDriver::_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_ucsr3c = (UCSR3C & ~0x07) | (_ucsr3c & (0x07));
UCSR3C = new_ucsr3c;
/* set the device baud rate */
UBRR3 = _ubrr3;
_cs_pin->write(0);
}
void AVRSPI3DeviceDriver::_cs_release() {
_cs_pin->write(1);
}
uint8_t AVRSPI3DeviceDriver::_transfer(uint8_t data) {
/* Wait for empty transmit buffer */
while ( !( UCSR3A & _BV(UDRE3)) ) ;
/* Put data into buffer, sends the data */
UDR3 = data;
/* Wait for data to be received */
while ( !(UCSR3A & _BV(RXC3)) ) ;
/* Get and return received data from buffer */
return UDR3;
}
void AVRSPI3DeviceDriver::_transfer(const uint8_t *data, uint16_t len) {
while (len--) {
/* Wait for empty transmit buffer */
while ( !( UCSR3A & _BV(UDRE3)) ) ;
/* Put data into buffer, sends the data */
UDR3 = *data++;
/* Wait for data to be received */
while ( !(UCSR3A & _BV(RXC3)) ) ;
// dummy read of UDR3 to complete
UDR3;
}
}
void AVRSPI3DeviceDriver::transaction(const uint8_t *tx, uint8_t *rx,
uint16_t len) {
_cs_assert();
if (rx == NULL) {
_transfer(tx, len);
} else {
for (uint16_t i = 0; i < len; i++) {
rx[i] = _transfer(tx[i]);
}
}
_cs_release();
}
void AVRSPI3DeviceDriver::cs_assert() {
_cs_assert();
}
void AVRSPI3DeviceDriver::cs_release() {
_cs_release();
}
uint8_t AVRSPI3DeviceDriver::transfer(uint8_t data) {
return _transfer(data);
}
void AVRSPI3DeviceDriver::transfer(const uint8_t *data, uint16_t len) {
_transfer(data, len);
}
#endif