uint8_t check_checksum() {
// Checksum for 'GP'
uint8_t chksum = 'G' ^ 'P';
uint8_t i = 0, num_len = 0;
char num_buf[4];
while (i < (GPS_CMD_BUF - 2)) {
if (gps_data[i] != '*') {
chksum ^= gps_data[i];
} else {
break;
}
i++;
}
if (i == (GPS_CMD_BUF - 2))
return E_LEN_ERROR;
stoh(chksum, num_buf, &num_len);
if (num_len == 2) {
if (gps_data[i + 1] == '0' && gps_data[i + 2] == num_buf[0])
return E_OK;
} else if (num_len == 3) {
if (gps_data[i + 1] == num_buf[0] && gps_data[i + 2] == num_buf[1])
return E_OK;
} else {
return E_LEN_ERROR;
}
return E_CHKSUM_ERROR;
}
uint8_t Gallery::begin(Serial_LCD * lcd0, String name) {
uint8_t a;
_pscreen = lcd0;
String text;
String s[5];
_name = name;
// check SD-card
if ( _pscreen->checkSD()==false ) {
a = _pscreen->initSD();
if ( _pscreen->checkSD()==false ) return 0;
}
// check .GCI and .DAT files
a = _pscreen->findFile(_name + ".gci");
if (a==0x15) return 0;
a = _pscreen->findFile(_name + ".dat");
if (a==0x15) return 0;
a = _pscreen->openTextFileDelimiter(_name+".dat", '\n');
if (a==0x15) return 0;
while (_pscreen->nextTextFileDelimiter(&text)) {
// clean and split
text = text.trim();
splitString(text, ' ', s, 5);
// store
image_t _image;
_gallery.push_back(_image);
_gallery[_gallery.size()-1].msb = stoh(s[2]);
_gallery[_gallery.size()-1].lsb = stoh(s[1]);
_gallery[_gallery.size()-1].x = stoh(s[3]);
_gallery[_gallery.size()-1].y = stoh(s[4]);
}
_index = 0;
return _gallery.size();
}
void gps_write_cmd(uint8_t * cmd_buf, uint8_t len) {
uint8_t chksum = 0, i, num_len = 0;
char num_buf[4];
for (i = 0; i < len; i++)
chksum ^= cmd_buf[i];
chIOPut(&GPS_SERIAL, '$');
sdWrite(&GPS_SERIAL, cmd_buf, len);
chIOPut(&GPS_SERIAL, '*');
stoh(chksum, num_buf, &num_len);
sdWrite(&GPS_SERIAL, num_buf, num_len - 1);
chIOPut(&GPS_SERIAL, '\r');
chIOPut(&GPS_SERIAL, '\n');
}
