mirror of https://github.com/ArduPilot/ardupilot
68 lines
2.0 KiB
C++
68 lines
2.0 KiB
C++
#include <AP_HAL/AP_HAL.h>
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#if CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_PXF || \
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CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_ERLEBOARD
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#include "RCInput_PRU.h"
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#include <errno.h>
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#include <fcntl.h>
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#include <poll.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <sys/time.h>
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#include <unistd.h>
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#include "GPIO.h"
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#define RCIN_PRUSS_SHAREDRAM_BASE 0x4a312000
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extern const AP_HAL::HAL& hal;
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using namespace Linux;
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void RCInput_PRU::init()
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{
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int mem_fd = open("/dev/mem", O_RDWR|O_SYNC|O_CLOEXEC);
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if (mem_fd == -1) {
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AP_HAL::panic("Unable to open /dev/mem");
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}
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ring_buffer = (volatile struct ring_buffer*) mmap(0, 0x1000, PROT_READ|PROT_WRITE,
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MAP_SHARED, mem_fd, RCIN_PRUSS_SHAREDRAM_BASE);
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close(mem_fd);
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ring_buffer->ring_head = 0;
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_s0_time = 0;
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// enable the spektrum RC input power
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hal.gpio->pinMode(BBB_P8_17, HAL_GPIO_OUTPUT);
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hal.gpio->write(BBB_P8_17, 1);
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}
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/*
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called at 1kHz to check for new pulse capture data from the PRU
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*/
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void RCInput_PRU::_timer_tick()
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{
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while (ring_buffer->ring_head != ring_buffer->ring_tail) {
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if (ring_buffer->ring_tail >= NUM_RING_ENTRIES) {
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// invalid ring_tail from PRU - ignore RC input
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return;
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}
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if (ring_buffer->buffer[ring_buffer->ring_head].pin_value == 1) {
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// remember the time we spent in the low state
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_s0_time = ring_buffer->buffer[ring_buffer->ring_head].delta_t;
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} else {
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// the pulse value is the sum of the time spent in the low
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// and high states
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_process_rc_pulse(_s0_time, ring_buffer->buffer[ring_buffer->ring_head].delta_t);
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}
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// move to the next ring buffer entry
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ring_buffer->ring_head = (ring_buffer->ring_head + 1) % NUM_RING_ENTRIES;
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}
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}
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#endif // CONFIG_HAL_BOARD_SUBTYPE
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