Wire.write slow, millis wrong

[zdjurisic]

Writing to a 7-segment display on I2c run 100 writes full speed in just under 8 seconds (timed by stopwatch in my hand). Timed by millis, returned 78 milliseconds. The same display, same code, just Wire instead of XWire, in the first line, on Mega2560 run in 33 milliseconds, and was, as expected, too quick to be timed by stopwatch.

Here's Arduino code:

`#include

void setup() { Serial.begin(57600); Wire.begin();

I2CWrite(0x00, 0x0C, 0x01); // AS1115 is in shutdown on power-up. Wake up & reset feature register. I2CWrite(0x00, 0x0B, 0x06); // Set scan limit to display 6 digits (no digit 7 on this display unit). I2CWrite(0x00, 0x09, B11111111); // Set all digits to "HEX decode"

unsigned long timeStart = millis(); for (byte j=0; j<10; j++) { for (byte i=0; i<10; i++) { Wire.beginTransmission(0x00); Wire.write(7); Wire.write(i); // This is teh address of the display digit we are writing to Wire.endTransmission(); } } unsigned long timeEnd = millis(); Serial.println(timeEnd-timeStart); }

void loop() {}`

[bombasticbob]

thanks, I'll have a look and see why it might be messing up the millis counter. it might be missing an interrupt [which means re-prioritizing them, probably].