UNRELIABLE LCD RESULTS 16:54:22.260 -> ******************************************************************** 16:54:22.327 -> Serial Initialized 16:54:22.360 -> -------------------------------------------------------------------- 16:54:22.426 -> I2CexpDiag - i2c LCD i/o expander backpack diagnostic tool 16:54:22.492 -> -------------------------------------------------------------------- 16:54:22.559 -> hd44780 lib version: 1.3.2 16:54:22.592 -> -------------------------------------------------------------------- 16:54:22.658 -> Reported Arduino Revision: 1.8.13 16:54:22.691 -> CPU ARCH: AVR - F_CPU: 16000000 16:54:22.724 -> -------------------------------------------------------------------- 16:54:22.791 -> SDA digital pin: 18 A4 16:54:22.824 -> SCL digital pin: 19 A5 16:54:22.857 -> -------------------------------------------------------------------- 16:54:22.923 -> Checking for required external I2C pull-up on SDA - NO 16:54:22.990 -> Checking for required external I2C pull-up on SCL - NO 16:54:23.056 -> Checking for I2C pins shorted together - Not Shorted 16:54:23.188 -> ******************************************************************** 16:54:23.255 -> WARNING: I2C requires external pullups for proper operation 16:54:23.321 -> It may appear to work without them, but may be unreliable and slower 16:54:23.388 -> Do not be surprised if it fails to work correctly 16:54:23.454 -> Install external pullup resistors to ensure proper I2C operation 16:54:23.520 -> ******************************************************************** 16:54:23.587 -> -------------------------------------------------------------------- 16:54:23.653 -> Scanning i2c bus for devices.. 16:54:23.686 -> i2c device found at address 0x27 16:54:23.753 -> Total I2C devices found: 1 16:54:23.786 -> -------------------------------------------------------------------- 16:54:23.852 -> Scanning i2c bus for all lcd displays (4 max) 16:54:23.952 -> LCD at address: 0x27 | config: P01245673H | R/W control: Yes 16:54:25.145 -> Total LCD devices found: 1 16:54:25.178 -> -------------------------------------------------------------------- 16:54:25.245 -> LCD Display Memory Test 16:54:25.278 -> Display: 0 16:54:25.311 -> Walking 1s data test: PASSED 16:54:25.378 -> Address line test: 16:54:25.411 -> Compare error: addr: 0 read 10 != wrote 0 16:54:25.477 -> Compare error: addr: 1 read 11 != wrote 1 16:54:25.510 -> Compare error: addr: 2 read 12 != wrote 2 16:54:25.556 -> Compare error: addr: 3 read 13 != wrote 3 16:54:25.610 -> Compare error: addr: 4 read 14 != wrote 4 16:54:25.643 -> Compare error: addr: 5 read 15 != wrote 5 16:54:25.676 -> Compare error: addr: 6 read 16 != wrote 6 16:54:25.742 -> Compare error: addr: 7 read 17 != wrote 7 16:54:25.842 -> 16:54:25.842 -> Compare error: addr: 40 read 50 != wrote 40 16:54:25.875 -> Compare error: addr: 41 read 51 != wrote 41 16:54:25.941 -> Compare error: addr: 42 read 52 != wrote 42 16:54:25.974 -> Compare error: addr: 43 read 53 != wrote 43 16:54:26.041 -> Compare error: addr: 44 read 54 != wrote 44 16:54:26.074 -> Compare error: addr: 45 read 55 != wrote 45 16:54:26.140 -> Compare error: addr: 46 read 56 != wrote 46 16:54:26.173 -> Compare error: addr: 47 read 57 != wrote 47 16:54:26.239 -> Compare error: addr: 5C read 4C != wrote 5C 16:54:26.273 -> Compare error: addr: 5D read 4D != wrote 5D 16:54:26.306 -> Compare error: addr: 5E read 4E != wrote 5E 16:54:26.372 -> Compare error: addr: 5F read 4F != wrote 5F 16:54:26.406 -> FAILED 16:54:26.439 -> Memory test failures are usually due to poor solder connections 16:54:26.505 -> Most common cause is poor solder joints on pins soldered to the LCD 16:54:26.571 -> 16:54:26.571 -> -------------------------------------------------------------------- 16:54:26.638 -> No working LCD devices 16:56:09.636 -> WORKING LCD RESULTS 16:56:09.636 -> ******************************************************************** 16:56:09.702 -> Serial Initialized 16:56:09.735 -> -------------------------------------------------------------------- 16:56:09.801 -> I2CexpDiag - i2c LCD i/o expander backpack diagnostic tool 16:56:09.868 -> -------------------------------------------------------------------- 16:56:09.934 -> hd44780 lib version: 1.3.2 16:56:09.967 -> -------------------------------------------------------------------- 16:56:10.034 -> Reported Arduino Revision: 1.8.13 16:56:10.067 -> CPU ARCH: AVR - F_CPU: 16000000 16:56:10.100 -> -------------------------------------------------------------------- 16:56:10.166 -> SDA digital pin: 18 A4 16:56:10.199 -> SCL digital pin: 19 A5 16:56:10.232 -> -------------------------------------------------------------------- 16:56:10.299 -> Checking for required external I2C pull-up on SDA - YES 16:56:10.365 -> Checking for required external I2C pull-up on SCL - YES 16:56:10.431 -> Checking for I2C pins shorted together - Not Shorted 16:56:10.564 -> -------------------------------------------------------------------- 16:56:10.630 -> Scanning i2c bus for devices.. 16:56:10.663 -> i2c device found at address 0x27 16:56:10.730 -> Total I2C devices found: 1 16:56:10.763 -> -------------------------------------------------------------------- 16:56:10.829 -> Scanning i2c bus for all lcd displays (4 max) 16:56:10.929 -> LCD at address: 0x27 | config: P01245673H | R/W control: Yes 16:56:12.122 -> Total LCD devices found: 1 16:56:12.155 -> -------------------------------------------------------------------- 16:56:12.222 -> LCD Display Memory Test 16:56:12.255 -> Display: 0 16:56:12.255 -> Walking 1s data test: PASSED 16:56:12.354 -> Address line test: PASSED 16:56:12.620 -> -------------------------------------------------------------------- 16:56:12.686 -> Each working display should have its backlight on 16:56:12.753 -> and be displaying its #, address, and config information 16:56:12.819 -> If all pixels are on, or no pixels are showing, but backlight is on, try adjusting contrast pot 16:56:12.919 -> If backlight is off, wait for next test 16:56:22.899 -> -------------------------------------------------------------------- 16:56:22.965 -> Blinking backlight test: to verify BL level autodetection 16:56:23.032 -> If backlight is mostly off but 16:56:23.065 -> you briefly see "BL Off" on display with backlight on, 16:56:23.131 -> then the library autodetected incorrect BL level 16:56:23.164 -> and the library cannot autoconfigure the device 16:56:33.445 -> -------------------------------------------------------------------- 16:56:33.511 -> Displaying 'uptime' on all displays 16:56:33.544 -> --------------------------------------------------------------------