70 lines
2.8 KiB
C++
70 lines
2.8 KiB
C++
#include "Arduino.h"
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#include "variables.h"
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#define SBUS_MIN_OFFSET 173
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#define SBUS_MID_OFFSET 992
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#define SBUS_MAX_OFFSET 1811
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#define SBUS_CHANNEL_NUMBER 16
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#define SBUS_PACKET_LENGTH 25
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#define SBUS_FRAME_HEADER 0x0f
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#define SBUS_FRAME_FOOTER 0x00
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#define SBUS_FRAME_FOOTER_V2 0x04
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#define SBUS_STATE_FAILSAFE 0x08
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#define SBUS_STATE_SIGNALLOSS 0x04
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/*
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Precomputed mapping from 990-2010 to 173:1811
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equivalent to
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map(channels[i], RC_CHANNEL_MIN, RC_CHANNEL_MAX, SBUS_MIN_OFFSET, SBUS_MAX_OFFSET);
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*/
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int mapChannelToSbus(int in) {
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return (((long) in * 1605l) / 1000l) - 1417;
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}
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void sbusPreparePacket(uint8_t packet[], int channels[], bool isSignalLoss, bool isFailsafe){
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static int output[SBUS_CHANNEL_NUMBER] = {0};
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/*
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* Map 1000-2000 with middle at 1500 chanel values to
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* 173-1811 with middle at 992 S.BUS protocol requires
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*/
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for (uint8_t i = 0; i < SBUS_CHANNEL_NUMBER; i++) {
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output[i] = mapsChannelToSbus(channels[i]);
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}
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uint8_t stateByte = 0x00;
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if (isSignalLoss) {
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stateByte |= SBUS_STATE_SIGNALLOSS;
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}
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if (isFailsafe) {
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stateByte |= SBUS_STATE_FAILSAFE;
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}
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packet[0] = SBUS_FRAME_HEADER; //Header
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packet[1] = (uint8_t) (output[0] & 0x07FF);
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packet[2] = (uint8_t) ((output[0] & 0x07FF)>>8 | (output[1] & 0x07FF)<<3);
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packet[3] = (uint8_t) ((output[1] & 0x07FF)>>5 | (output[2] & 0x07FF)<<6);
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packet[4] = (uint8_t) ((output[2] & 0x07FF)>>2);
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packet[5] = (uint8_t) ((output[2] & 0x07FF)>>10 | (output[3] & 0x07FF)<<1);
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packet[6] = (uint8_t) ((output[3] & 0x07FF)>>7 | (output[4] & 0x07FF)<<4);
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packet[7] = (uint8_t) ((output[4] & 0x07FF)>>4 | (output[5] & 0x07FF)<<7);
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packet[8] = (uint8_t) ((output[5] & 0x07FF)>>1);
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packet[9] = (uint8_t) ((output[5] & 0x07FF)>>9 | (output[6] & 0x07FF)<<2);
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packet[10] = (uint8_t) ((output[6] & 0x07FF)>>6 | (output[7] & 0x07FF)<<5);
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packet[11] = (uint8_t) ((output[7] & 0x07FF)>>3);
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packet[12] = (uint8_t) ((output[8] & 0x07FF));
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packet[13] = (uint8_t) ((output[8] & 0x07FF)>>8 | (output[9] & 0x07FF)<<3);
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packet[14] = (uint8_t) ((output[9] & 0x07FF)>>5 | (output[10] & 0x07FF)<<6);
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packet[15] = (uint8_t) ((output[10] & 0x07FF)>>2);
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packet[16] = (uint8_t) ((output[10] & 0x07FF)>>10 | (output[11] & 0x07FF)<<1);
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packet[17] = (uint8_t) ((output[11] & 0x07FF)>>7 | (output[12] & 0x07FF)<<4);
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packet[18] = (uint8_t) ((output[12] & 0x07FF)>>4 | (output[13] & 0x07FF)<<7);
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packet[19] = (uint8_t) ((output[13] & 0x07FF)>>1);
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packet[20] = (uint8_t) ((output[13] & 0x07FF)>>9 | (output[14] & 0x07FF)<<2);
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packet[21] = (uint8_t) ((output[14] & 0x07FF)>>6 | (output[15] & 0x07FF)<<5);
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packet[22] = (uint8_t) ((output[15] & 0x07FF)>>3);
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packet[23] = stateByte; //Flags byte
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packet[24] = SBUS_FRAME_FOOTER; //Footer
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} |