dhars
July 9, 2024, 8:55pm
1
I need help to decode the raw delta-x and delta-y data from the TX/RX serial pins on the Optical Flow Lidar Sensor SKU: 3901-L0X. What do each of these bytes represent?
Baud rate: 115200
Sample of Output:
dhars
July 9, 2024, 8:58pm
2
#include <SoftwareSerial.h>
SoftwareSerial flowSerial = SoftwareSerial(2,3);
char msg[256];
void setup() {
// put your setup code here, to run once:
Serial.begin(115200);
flowSerial.begin(115200);
Serial.setTimeout(10);
}
void loop() {
// put your main code here, to run repeatedly:
int n;
if( flowSerial.available()){
flowSerial.readBytes(msg,32);
for( n = 0; n < 32; n++){
// z = (int)(word(msg[n + 1], msg[n]));
Serial.print(msg[n],HEX);
Serial.print(" ");
}
Serial.println();
}
delay(1000);
}
lida2003
July 9, 2024, 10:09pm
3
Sorry about the links and descriptions, I have re-checked your binary hex output.
I have did some study about ArduPilot开源飞控之AP_OpticalFlow
If you are using MatekSys Optical Flow 3901-L0X , then you need to configure SERIALx_PROTOCL=32. It’s MSP by default, and which is confirmend from you binary hex log SOF=0x24, V2=0x58.
using namespace MSP;
// detect the device
AP_OpticalFlow_MSP *AP_OpticalFlow_MSP::detect(AP_OpticalFlow &_frontend)
{
// we assume msp messages will be sent into this driver
return NEW_NOTHROW AP_OpticalFlow_MSP(_frontend);
}
// read latest values from sensor and fill in x,y and totals.
void AP_OpticalFlow_MSP::update(void)
{
// record gyro values as long as they are being used
// the sanity check of dt below ensures old gyro values are not used
if (gyro_sum_count < 1000) {
const Vector3f& gyro = AP::ahrs().get_gyro();
gyro_sum.x += gyro.x;
gyro_sum.y += gyro.y;
gyro_sum_count++;
}
return 0;
}
// Send the frame
return msp_serial_send_frame(msp, hdr_buf, hdr_len, sbuf_ptr(&packet->buf), data_len, crc_buf, crc_len);
}
/*
ported from betaflight/src/main/msp/msp_serial.c
*/
bool MSP::msp_parse_received_data(msp_port_t *msp, uint8_t c)
{
switch (msp->c_state) {
default:
case MSP_IDLE: // Waiting for '$' character
if (c == '$') {
msp->msp_version = MSP_V1;
msp->c_state = MSP_HEADER_START;
} else {
return false;
}
BTW, there are different kind of protocol for optical flow, so I have made a mistake previously. Check here for details.
Oli1
July 10, 2024, 9:10am
4
You should start by formatting the output (which looks like an input) correctly:
24 58 3C 0 1 1F 5 0 FFFFFFFF 6B 1 0 0 FFFFFFC4
24 58 3C 0 1 1F 24 5C 3C 0 1 1F 5 0 69 40 0 FFFFFFFA
24 58 3C 0 1 1F 5 0 FFFFFFFF 6B 1 0 0 FFFFFFC5
24 58 3C 0 1 1F 00
24 58 3C 0 1 1F 5 0 FFFFFFFF 63 1 0 0 FFFFFF92
24 58 3C 0 1 1F 5 0 FFFFFFFF 6C 1 0 0 FFFFFFCB
24 58
24 58 3C 0 1 1F 5 0 FFFFFFFF 70 1 0 0 FFFFFFF3
24 58 3C 0 1 1F 5 0 FFFFFFFF 6B 1 0 0 FFFFFFC5
24 58 3C 0
24 58 3C 0 1 1F 5 0 FFFFFFFF 6D 1 0 0 FFFFFF8E
24 58 3C 0 1 1F 5 0 FFFFFFFF 65 1 0 0 FFFFFFD9
24 58 3C 0
24 58 3C 0 1 1F 5 0 FFFFFFFF 72 1 0 0 79
24 58 3C 0 1 1F 5 0 FFFFFFFF 68 1 0 0 A
24 58 3C 0
24 58 3C 0 1 1F 5 0 FFFFFFFF 72 1 0 0 79
24 58 3C 0 1 1F 4 0 FFFFFFFF 60 1 0 0 5D
1 Like
Oli1
July 10, 2024, 3:04pm
5
Here’s a start, MSP must be one of the worst documented protocols in history…:
Header | Direction | Flag | Function | Payload Length | 0 | Payload | CRC
24 58 | 3C | 0 | 1 1F | 5 | 0 | FFFFFFFF 6B 1 0 0 | FFFFFFC4
$ X | < | 0 | 287 | 5 | 0 | FFFFFFFF 6B 1 0 0 | FFFFFFC4
MSP V2 | FC->Sensor | 0 | you'll need to look through the code for function and payload