A trial parser code in Arduino decode X-Plane UDP data-gram, a sample data array assigned for trial:
In the Sample, data of the output Packet: Pitch, roll, heading:
pitch, deg
The aircraft’s pitch, measured in body-axis Euler angles.
roll, deg
The aircraft’s roll, measured in body-axis Euler angles.
hding, true
The aircraft’s true heading, measured in body-axis Euler angles.
hding, mag
The aircraft’s magnetic heading, in degrees.
The UDP data-gram sample, 41 byte:
444154412A11000000DC5C7E3F285277BED1DFCB415862E3410C0790400C079C400C079C400C07914
444154412A11 = DATA*(tab)
000000 = Index
Data 8*4byte
DC5C7E3F:285277BE
D1DFCB41:5862E341
00C079C4:00C079C4
00C079C4:00C079C4
The meaning of test data-gram in index number:
Head=0-5, index=6-8, pitch=9-12, roll=13-16, true=17-20, mag=21-24, null=25-40
Swap endiannes Hex to floating point:
DC5C7E3F => 3F7E5CDC = 0.993604 pitch
285277BE => BE775228 = -0.241524 roll
D1DFCB41 => 41CBDFD1 = 25.4843 heading(true)
5862E341 => 41E36258 = 28.423 heading(magnetic)
00C079C4 => C479C000 = -999
00C079C4 => C479C000 = -999
00C079C4 => C479C000 = -999
00C079C4 => C479C000 = -999
float to Hex calculation: https://gregstoll.com/~gregstoll/floattohex/
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Arduino Program:
// Demo to decode the X-Plane UDP data packet from swap endianness HEX to 32bit floting point convertion.
char testdata[] = {
0x44, 0x41, 0x54, 0x41, 0x2A, 0x11, 0x00, 0x00, 0x01,
0xDC, 0x5C, 0x7E, 0x3F,
0x28, 0x52, 0x77, 0xBE,
0xD1, 0xDF, 0xCB, 0x41,
0x58, 0x62, 0xE3, 0x41,
0x00, 0xC0, 0x79, 0xC4,
0x00, 0xC0, 0x79, 0xC4,
0x00, 0xC0, 0x79, 0xC4,
0x00, 0xC0, 0x79, 0xC4,
};
long t;
int packet_index;
int x;
const char* head = "DATA*";
void setup() {
Serial.begin(115200);
}
void loop() {
Serial.printf("\nUDP packet contents:\n");
// data-gram header text = DATA*
for (int idx = 0; idx <= sizeof(head) ; idx++)
{
Serial.print(testdata[idx]);
}
// data-gram idx:
packet_index = (testdata[6]<<16)+(testdata[7]<<8)+(testdata[8]);
Serial.println(packet_index);
// Only 8 data in one packet, idx will start at
// 1=idx(9), 2=idx(13), 3=17, 4=21, 5=25, 6=29, 7=33, 8=37.
for (int idx = 9; idx <41 ; idx = idx + 4)
{
// swap endiness hex to floting point convertion.
t = (testdata[idx+3]<<24)+(testdata[idx+2]<<16)+(testdata[idx+1]<<8)+(testdata[idx]);
Serial.println(*(float*) &t, 6);
}
// below just display the original data-gram from UDP packet.
Serial.println("UDP original Data-gram:");
for (int idx = 0; idx < sizeof(testdata) ; idx++)
{
if (idx <= 8){
Serial.print(testdata[idx]);
}
else {
if (idx == 9) Serial.print("\n");
if (testdata[idx]<15) Serial.print("0");
Serial.print(testdata[idx], HEX);
x += 1;
if (x == 4 || x == 8 || x == 12)Serial.print(":");
else if (x == 16){
Serial.print("\n");
x = 0;
}
}
}
delay(5000);
}
