Did some more tests and USB Type does have some influence.
With this new test I get opposite results
Code:
#include <SPI.h>
#include <RA8875.h>
//teensy4 SPI0 RA8875
#define TFT_CS 10
#define TFT_RST 9 // 255 = unused, connect to 3.3V
#define TFT_MOSI 11
#define TFT_SCLK 13
#define TFT_MISO 12
RA8875 tft = RA8875(TFT_CS, TFT_RST, TFT_MOSI, TFT_SCLK, TFT_MISO);
void setup(){
while (!Serial && millis() < 2500);
tft.begin(RA8875_800x480);
}
void loop(){
tft.fillWindow(RA8875_BLACK);
uint32_t msec = millis();
for(int x = 0; x < 800; x += 10){
for(int y = 0; y < 480; y += 10){
// tft.drawRect(x , y, 8, 8, RA8875_YELLOW);
// tft.fillRect(x+2 , y+2, 4, 4, RA8875_YELLOW);
tft.setCursor(x, y);
tft.print("Z");
}
}
msec = millis() - msec;
Serial.print(msec);
Serial.println(" ms/page");
}
USB Type : Raw HID
USB Type : MIDI
Code:
572 ms/page
591 ms/page
588 ms/page
621 ms/page
604 ms/page
607 ms/page
617 ms/page
604 ms/page
594 ms/page
630 ms/page
612 ms/page
596 ms/page
601 ms/page
598 ms/page
618 ms/page
619 ms/page
617 ms/page
623 ms/page
640 ms/page
649 ms/page
656 ms/page
665 ms/page
657 ms/page
656 ms/page
660 ms/page
639 ms/page
643 ms/page
653 ms/page
USB Type : Serial
USB Type : Serial + MIDI
Code:
964 ms/page
959 ms/page
979 ms/page
959 ms/page
997 ms/page
1027 ms/page
1028 ms/page
1045 ms/page
1042 ms/page
1059 ms/page
1067 ms/page
1072 ms/page
1062 ms/page
1135 ms/page
1137 ms/page
1122 ms/page
1129 ms/page
1088 ms/page
1141 ms/page
1211 ms/page
1184 ms/page
1217 ms/page
1185 ms/page
1218 ms/page
1209 ms/page
1247 ms/page
1294 ms/page
1278 ms/page
1248 ms/page
1263 ms/page
1304 ms/page
1307 ms/page
1320 ms/page
1331 ms/page
1333 ms/page
1348 ms/page
1357 ms/page
1345 ms/page
1345 ms/page
1370 ms/page
1420 ms/page
1398 ms/page
1448 ms/page
1412 ms/page
1409 ms/page
1438 ms/page
1409 ms/page
1441 ms/page
Time slowly creeps up.
Re-uploading the code and the previous creep is still there.
Power cycling the T4 for 10sec and the creep starts from zero again.
Reverting back to beta2
USB Type : Serial
gives a solid
USB Type : Raw HID
USB Type : MIDI
give a solid