Derek Calland

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7 years, 1 month ago.

I2C Display 20x4 Character write frequency

If I use the following code below with wait set at 0.01, then rows 2,3 and 4 get progressively worse in visibly displaying characters. Changing the wait to a 1 each row is displayed perfect. My thoughts initially were if I used a small enough wait value then the frequency in writing characters would increase and I wouldn't see the difference. Am I correct in thinking this is related to the I2C frequency and the conversion taking place on the LCD display chip? Are there variable anywhere where I can look at changing? Thanks for any help.

lcd.cls();
        lcd.printf("ITG3200 DevID 0x%02X\n",gyro.getWhoAmI()); //was gyro1.getWhoAmI()
        wait(0.01);
        lcd.printf("ADXL DevID is: 0x%02X\n", accelerometer.getDeviceID());
        wait(0.01);
        lcd.printf("Ax%i Ay%i Az%i\n", (int16_t)readings[0], (int16_t)readings[1], (int16_t)readings[2]);
        wait(0.01);
        lcd.printf("Gx%i Gy%i Gz%i\n\r", gyro.getGyroX(), gyro.getGyroY(), gyro.getGyroZ());
        //lcd.printf("Temperature %2.1f \n",gyro.getTemperature());
        wait(0.01);

Apologies using this code I have the display working how I want it, but now I have a character appearing I haven't noticed before right at the very end and on another line? I have no idea where this additional character is coming from as it displaces the lines above it?

lcd.cls();
        //lcd.printf("ITG3200 DevID 0x%02X\n",gyro.getWhoAmI()); //was gyro1.getWhoAmI()
        //lcd.printf("ADXL DevID is: 0x%02X\n", accelerometer.getDeviceID());
        lcd.printf("Ax%i Ay%i Az%i\n\n", (int16_t)readings[0], (int16_t)readings[1], (int16_t)readings[2]);
        lcd.printf("Gx%i Gy%i Gz%i\n\r", gyro.getGyroX(), gyro.getGyroY(), gyro.getGyroZ());
        //lcd.printf("Temperature %2.1f \n",gyro.getTemperature());
        wait(0.5);
posted by Derek Calland 09 Mar 2017

To help I've put the Temperature display back in on the next line and the strange character appears directly in front of the T on Line 4 Position 1??

posted by Derek Calland 09 Mar 2017
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