ardupilot/libraries/AP_HAL_Linux/RCInput_PRU.h
Andrew Tridgell 2ce219aeb8 HAL_Linux: split RCInput class into generic and PRU implementations
this will make it easier for other boards (such as NAVIO) to implement
their own RCInput mechanism
2014-08-19 20:03:33 +10:00

38 lines
934 B
C++

#ifndef __AP_HAL_LINUX_RCINPUT_PRU_H__
#define __AP_HAL_LINUX_RCINPUT_PRU_H__
/*
This class implements RCInput on the BeagleBoneBlack with a PRU
doing the edge detection of the PPM sum input
*/
#include <AP_HAL_Linux.h>
#define RCIN_PRUSS_SHAREDRAM_BASE 0x4a312000
#define NUM_RING_ENTRIES 200
class Linux::LinuxRCInput_PRU : public Linux::LinuxRCInput
{
public:
void init(void*);
void _timer_tick(void);
private:
// shared ring buffer with the PRU which records pin transitions
struct ring_buffer {
volatile uint16_t ring_head; // owned by ARM CPU
volatile uint16_t ring_tail; // owned by the PRU
struct {
uint16_t pin_value;
uint16_t delta_t;
} buffer[NUM_RING_ENTRIES];
};
volatile struct ring_buffer *ring_buffer;
// time spent in the low state
uint16_t _s0_time;
};
#endif // __AP_HAL_LINUX_RCINPUT_PRU_H__