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9 years, 4 months ago.
TextLCD16x2で半分しか表示されない
mbedを使い始めた初心者です． ”HD44780 Text LCD”を使ってLCD表示をトライしているのですがうまく表示されません．
lcd.printf("Hello World!\r\n");
lcd.printf("123456789\n");
とプログラミングしたのですがLCDには
”Hello Wo■■■■■■■■”
”12345678■■■■■■■■”
と表示され，後ろ8文字が”■”表示になってしまいます
一応文字は表示されるので，pin接続に間違いはないと思いますが， 解決のヒントをいただけないでしょうか？
使用機器は以下の通りです
・mbed：TG LPC11U35-501
・LCD：TC1602E-25A (メーカー：Linkman，3.3V駆動 )
よろしくお願いします
1 Answer
9 years, 4 months ago.
Hello Tomozo,
the wiring between mbed and the LCD must be OK since commands and data are received and you get some text on the display. The contrast voltage on pin3 of the LCD is also OK otherwise you would not see anything. It looks like the right hand side of the display (rightmost 8 characters on both lines) is not working. That part has a special driver that is connected to the actual LCD controller (HD44780 or compatible). Most likely cause of the problem is a defective driver IC. It will be hard to repair or replace that component unless you see any damaged PCB traces on the display. Best solution is to get a new LCD display and test your software again. There is a second possible cause of the problem. Check that the power supply is correct. Is it really 3V3 or perhaps a bit too low which leads to a functioning controller while the driver does not work because it is just out of spec. A quick google search came up with a valid voltage range between 3V1 and 3V5.