Hi,
Today I run first test on my custom board with Atmega 328.
my sensor setup is:
- L3G4200D
- ADXL345
- HMC5883
-BMP085
- and Mediatek GPS Gms‐u1LP - 10Hz + 115200 baud with custom firmware from GlobalTop.
http://download.maritex.com.pl/pdfs/wi/GPS-GMS-U1LP.pdfFirst I've made some changes to get it work on Atmegs328. I decide to create detecting procedure at startup. If MWC receive NMEA frames in first two seconds I set flag GPSdetected, then use this flag to dissable qui and enable GPS transmition. If I don't miss anything here are all changes:
Code: Select all
global declaration
...
static uint8_t GPSDetected = 0;
//--------------------------------------
annexCode()
...
if (!GPSDetected)
serialCom();
//--------------------------------------
setup() function
...
#if defined(GPS)
if (GPS_SERIAL != 0)
SerialOpen(GPS_SERIAL,GPS_BAUD);
//init GPS and detect GPS
GPS_init();
currentTime = micros();
while(1)
{
if (SerialAvailable(GPS_SERIAL))
//-----------------------------------
loop() function
...
if (rcData[YAW] < MINCHECK && rcData[PITCH] < MINCHECK && armed == 0) {
if (rcDelayCommand == 20) calibratingG=400;
GPS_fix_home = 0; //save home position again if gyro calibration occurs
...
#if defined(GPS)
if (GPSDetected)
while (SerialAvailable(GPS_SERIAL)) {
if (GPS_newFrame(SerialRead(GPS_SERIAL))) {
if (GPS_update == 1)
{
GPS_update = 0;
STABLEPIN_ON; //toggle led to see NMEA frames
}
else
{
GPS_update = 1;
STABLEPIN_OFF;
}
if (GPS_fix == 1 && GPS_numSat > 4) {
if (GPS_newFrame(SerialRead(GPS_SERIAL)))
{
GPSDetected = 1;
break;
}
if (micros() - currentTime > 2000000)
break;
}
...
in GPS file:
void GPS_init()
{
char init1[] = "$PMTK314,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*29\r\n"; //disable all messages except GPGGA
//char init2[] = "$PGCMD,21,1*6F\r\n"; <-binary mode
int i;
delay (50);
for (i = 0; i < sizeof(init1); i++)
SerialWrite(GPS_SERIAL,init1[i]);
}
Then I setup PID's for GPS: P=5 and D=5
Then I go outside. First I test head free mode and it works fine. Compass was tested using classic compass before and it show North correctly. then I fly forward me so about 20m and enable RTH. My quad start to fly right
Second test my quad start to fly left.
Conclusion:
GPS should works fine on arduino pro mini without any problems. My tests fails but the source of problems may be my setup. I try to isolate my MAG and GPS form other electronics, or I will try to test GPS when motors are running. Will try to read values on the PC.
Idea:
My module and many others have binary protocol too. I write function to parse binary frames and it is relay worth to switch to this frames. Code use less internal memory and ram works faster etc. But to be sure I've run this tests on NMEA protocol.
I also disable all frames except GPGGA it is correct ?
I will try to run more tests soon but today start snowing here (Poland) so it is to cold - maybe this is source of problem??? (all electronics are covered of course). I need to add MAG calibration patch from another post.
Marcin.
and i hope to understand what i'm trying to say. 
)
