There is no preloaded welcome screen on flash chip version due to it will saved in the flash chip start from address 0, and we keep this chip fresh when we deliver it to you.
The welcome screen is also commands set, so, you need to add show image command before the data of image, the only pure image data is not enough.
Yes, the 4 color pixels test screen are associate with configuraton showing command, if the configuration was turn off, the pixel test will be off.
Here is the test screen which can be saved as welcome screen:
const unsigned char startscreen[] = "CLGP\x14\x1DSF\x00SC\x01TTNOT NOT2 XOR XOR2\x00\
DM!FR\x14\x10\x54\x1D SC\x1F FR\x30\x10\x54\x1D\
DM^FR\x55\x10\xb4\x1D FR\x76\x10\xb4\x1D\
DMCSC\xE0 CC\x78\xFF\x04\x36\x01\
SC\x1C CC\x78\xFF\x04\x2C\x01\
SC\x03 CC\x78\xFF\x04\x22\x01\
DM|SC\xFC CC\x78\xFF\x04\x12\x01\
MA\x42\xCD\x35\x35\xfd\xfd\
BGC\xE3 MA\x79\xCD\x35\x35\x03\xfd\
BGC\x1F MA\x42\xFF\x04\x35\x35\xfd\x03\
BGC\xEC MA\x79\xFF\x04\x35\x35\x03\x03\
DMC BGC\x00 SC\xF0 SD1 GP\x30\x10 TTDIR 1...\x00\
SD2 GP\x30\x10 TTDIR 2...\x00\
SD3 GP\x30\x10 TTDIR 3...\x00\
SD0\
DWWIN\x00\x30\xa0\x80\
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\x7e\x7f\x53\x43\x60\x46\x52\x7e\x71\x84\x7f\x53\x43\x80\x46\x52\x85\x71\x8b\x7f\x53\x43\xa0\x46\x52\x8c\x71\x92\x7f\x53\x43\xc0\x46\x52\x92\x71\x98\x7f\x53\x43\xe0\x46\x52\x99\x71\x9f\x7f\
RSTDW\
ESC\x3f\x00\x00 ALIGN\x00SD\x01GP\xA0\x20TTLeft Alignment\x00\
ESC\x00\x3f\x00 ALIGN\x01SD\x01GP\xA0\x30TTMiddle Alignment\x00\
ESC\x00\x00\x3f ALIGN\x02SD\x01GP\xA0\x40TTRight Alignment\x00\
ALIGN\x00SC\x01GP\x00\x00SD\x00\xff\xff";
You can use: downloadStartScreen(sizeof(startscreen),startscreen); to save it to module.
void downloadStartScreen(int lon, const unsigned char *data) {
int j;
unsigned char b;
uint8_t c;
writeStr("SSS");
lon++;
write((uint8_t) (lon / 256));
write((uint8_t) (lon % 256));
delay(300);
b = 0;
for (j = 0; j < (lon - 1); j++) {
c = pgm_read_byte_near(data + j); //read data stored in code space in Arduino, other MCU are similar
write(c);
if ((++b) == 64) {
b = 0, delay(100);
}
}
write(255); //indicater of end of it
delay(100);
}