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Added parsing function. Everything works OK.
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TODO:
- Clean up the code
- Add uORB publishing messages

Signed-off-by: Claudio Micheli <claudio@auterion.com>
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@cmic0 @bkueng
cmic0 authored and bkueng committed Jan 15, 2019
1 parent 591e8fd commit 700fd56
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Showing 3 changed files with 213 additions and 13 deletions.
50 changes: 40 additions & 10 deletions src/drivers/distance_sensor/airlango/isl2950.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -362,23 +362,53 @@ ISL2950::collect()
perf_begin(_sample_perf);

/* clear buffer if last read was too long ago */
//int64_t read_elapsed = hrt_elapsed_time(&_last_read);
int64_t read_elapsed = hrt_elapsed_time(&_last_read);

// ----------------------- LANBAO SPECIFIC ---------------------------
//printf("enter ISL2950::collect() - reads from serial");
uint8_t buffer[50];
int bytes_available = 0;
// int bytes_processed = 0;
int bytes_read = 0;
// bool full_frame;
bytes_read = bytes_read;

bytes_read = ::read(_fd, buffer + bytes_available, 50 - bytes_available);
printf("read() returns %02X %02X %02X %02X \n", buffer[0], buffer[1],buffer[2],buffer[3] );
uint8_t buffer[50];
int bytes_available = 0;
int bytes_processed = 0;
int bytes_read = 0;
bool full_frame;
int distance_mm = -1.0f;

bytes_read = ::read(_fd, buffer + bytes_available, 50 - bytes_available);
//printf("read() returns %02X %02X %02X %02X \n", buffer[0], buffer[1],buffer[2],buffer[3] );


//--------------------------------------------------------------------
if (bytes_read < 0) {
PX4_ERR("isl2950 - read() error: %d \n", bytes_read);
perf_count(_comms_errors);
perf_end(_sample_perf);

/* only throw an error if we time out */
if (read_elapsed > (_conversion_interval * 2)) {
return bytes_read;

} else {
return -EAGAIN;
}

} else if (bytes_read == 0) {
return -EAGAIN; // SF0X drivers
// LANBAO driver
}

bytes_available += bytes_read;

// parse the buffer data
full_frame = false;
bytes_processed = isl2950_parser(buffer, bytes_available, &full_frame,&distance_mm);
bytes_processed = bytes_processed;
//printf("isl2950_parser() processed %d bytes, full_frame %d \n", bytes_processed, full_frame);
if (full_frame) {
printf("Measured Distance %d \n",distance_mm*100);
}


// ---------------------------- END EDIT
_last_read = hrt_absolute_time();
ret = OK;

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152 changes: 150 additions & 2 deletions src/drivers/distance_sensor/airlango/isl2950_parser.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -40,16 +40,164 @@
#include "isl2950_parser.h"
#include <string.h>
#include <stdlib.h>
#include <stdio.h>

#include "isl2950_parser.h"
#include <string.h>
#include <stdlib.h>

typedef unsigned char UCHAR;
typedef unsigned short USHORT;

int isl2950_parser(char c, char *parserbuf, unsigned *parserbuf_index, enum ISL2950_PARSE_STATE *state, float *dist)
// Note : No clue what those static variables are
static const UCHAR aucCRCHi[] = {
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40
};

static const UCHAR aucCRCLo[] = {
0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06, 0x07, 0xC7,
0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD, 0x0F, 0xCF, 0xCE, 0x0E,
0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09, 0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9,
0x1B, 0xDB, 0xDA, 0x1A, 0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC,
0x14, 0xD4, 0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,
0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3, 0xF2, 0x32,
0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4, 0x3C, 0xFC, 0xFD, 0x3D,
0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A, 0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38,
0x28, 0xE8, 0xE9, 0x29, 0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF,
0x2D, 0xED, 0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,
0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60, 0x61, 0xA1,
0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67, 0xA5, 0x65, 0x64, 0xA4,
0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F, 0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB,
0x69, 0xA9, 0xA8, 0x68, 0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA,
0xBE, 0x7E, 0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,
0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71, 0x70, 0xB0,
0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92, 0x96, 0x56, 0x57, 0x97,
0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C, 0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E,
0x5A, 0x9A, 0x9B, 0x5B, 0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89,
0x4B, 0x8B, 0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,
0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42, 0x43, 0x83,
0x41, 0x81, 0x80, 0x40
};

// TOF frame format
//
// 1B 1B 1B 1B 2B
// | 0xA5 | 0x5A | distance-MSB | distance-LSB | crc-16 |
//
// Frame data saved for CRC calculation
const static int TOF_DISTANCE_MSB_POS = 2;
const static int TOF_DISTANCE_LSB_POS = 3;
const static int TOF_CRC_CALC_DATA_LEN = 4;
static unsigned char frame_data[TOF_CRC_CALC_DATA_LEN] = {
TOF_SFD1, TOF_SFD2, 0, 0
};

USHORT usMBCRC16(UCHAR* pucFrame, USHORT usLen) {
UCHAR ucCRCHi = 0xFF;
UCHAR ucCRCLo = 0xFF;
int iIndex;
while (usLen--) {
iIndex = ucCRCLo ^ *(pucFrame++);
ucCRCLo = (UCHAR)(ucCRCHi ^ aucCRCHi[iIndex]);
ucCRCHi = aucCRCLo[iIndex];
}
return (USHORT)(ucCRCHi << 8 | ucCRCLo);
}

int isl2950_parser(const uint8_t* buffer, int length, bool* full_frame, int* dist)
{
static TofFramingState state = TFS_NOT_STARTED;
static uint16_t crc16 = 0;
int bytes_processed = 0;

// SOME STUFFS
while (bytes_processed < length) {
uint8_t b = buffer[bytes_processed++];
// printf("parse byte 0x%02X \n", b);

switch (state) {
case TFS_NOT_STARTED:
if (b == TOF_SFD1) {
state = TFS_GOT_SFD1;
// printf("Got SFD1 \n");
}
break;

case TFS_GOT_SFD1:
if (b == TOF_SFD2) {
state = TFS_GOT_SFD2;
// printf("Got SFD2 \n");
} else if (b == TOF_SFD1) {
state = TFS_GOT_SFD1;
// printf("Discard previous SFD1, Got new SFD1 \n");
} else {
state = TFS_NOT_STARTED;
}
break;

case TFS_GOT_SFD2:
frame_data[TOF_DISTANCE_MSB_POS] = b;
state = TFS_GOT_DATA1;
// printf("Got DATA1 0x%02X \n", b);
break;

case TFS_GOT_DATA1:
frame_data[TOF_DISTANCE_LSB_POS] = b;
state = TFS_GOT_DATA2;
// printf("Got DATA2 0x%02X \n", b);
// do crc calculation
crc16 = usMBCRC16(frame_data, TOF_CRC_CALC_DATA_LEN);
// convert endian
crc16 = (crc16 >> 8) | (crc16 << 8);
break;

case TFS_GOT_DATA2:
if (b == (crc16 >> 8)) {
state = TFS_GOT_CHECKSUM1;
} else {
// printf("Checksum invalid on high byte: 0x%02X, calculated: 0x%04X \n",b, crc16);
state = TFS_NOT_STARTED;
}
break;

case TFS_GOT_CHECKSUM1:
// Here, reset state to `NOT-STARTED` no matter crc ok or not
state = TFS_NOT_STARTED;
if (b == (crc16 & 0xFF)) {
printf("Checksum verified \n");
*dist = (frame_data[TOF_DISTANCE_MSB_POS] << 8) | frame_data[TOF_DISTANCE_LSB_POS];
*full_frame = true;
return bytes_processed;
} else {
printf("Checksum invalidon low byte: 0x%02X, calculated: 0x%04X \n",b, crc16);
}
break;

default:
printf("This should never happen. \n");
break;
}
}
// SOME STUFFS
return bytes_processed;
}
24 changes: 23 additions & 1 deletion src/drivers/distance_sensor/airlango/isl2950_parser.h
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Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,27 @@

#pragma once

// frame start delimiter
#define TOF_SFD1 0xA5
#define TOF_SFD2 0x5A

typedef enum {
TFS_NOT_STARTED = 0,
TFS_GOT_SFD1,
TFS_GOT_SFD2,
TFS_GOT_DATA1,
TFS_GOT_DATA2,
TFS_GOT_CHECKSUM1,
TFS_GOT_CHECKSUM2,
} TofFramingState;

enum IslWorkingMode {
KEEP_HEIGHT = 0,
NUM_WORKING_MODE
};


// SF0X STYLE
enum ISL2950_PARSE_STATE {
ISL2950_PARSE_STATE0_UNSYNC = 0,
ISL2950_PARSE_STATE1_SYNC,
Expand All @@ -50,4 +71,5 @@ enum ISL2950_PARSE_STATE {
ISL2950_PARSE_STATE6_GOT_CARRIAGE_RETURN
};

int isl2950_parser(char c, char *parserbuf, unsigned *parserbuf_index, enum ISL2950_PARSE_STATE *state, float *dist);

int isl2950_parser(const uint8_t* buffer, int length, bool* full_frame, int* dist);

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