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35 lines
918 B
35 lines
918 B
#pragma once |
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/* |
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This class implements RCInput on the BeagleBoneBlack with a PRU |
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doing the edge detection of the PPM sum input |
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*/ |
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#include "AP_HAL_Linux.h" |
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#define RCIN_PRUSS_SHAREDRAM_BASE 0x4a312000 |
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// we use 300 ring buffer entries to guarantee that a full 25 byte |
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// frame of 12 bits per byte |
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class Linux::RCInput_PRU : public Linux::RCInput |
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{ |
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public: |
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void init(); |
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void _timer_tick(void); |
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private: |
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static const unsigned int NUM_RING_ENTRIES=300; |
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// shared ring buffer with the PRU which records pin transitions |
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struct ring_buffer { |
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volatile uint16_t ring_head; // owned by ARM CPU |
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volatile uint16_t ring_tail; // owned by the PRU |
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struct { |
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uint16_t pin_value; |
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uint16_t delta_t; |
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} buffer[NUM_RING_ENTRIES]; |
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}; |
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volatile struct ring_buffer *ring_buffer; |
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// time spent in the low state |
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uint16_t _s0_time; |
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};
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