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notes:hd44780-vs-st7066 [19/11/2018 19:03] alez created |
notes:hd44780-vs-st7066 [19/11/2018 19:04] alez [Hack howto] |
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| -2.0 to -1.1 is a good contrast and -1.5 can be considered a good average. | -2.0 to -1.1 is a good contrast and -1.5 can be considered a good average. | ||
| - | ===== Hack howto ===== | + | ===== The Hack ===== |
| I have encountered (in an UniOp EK42) an interesting contrast control circuitry, fortunately designed to comprehend wide range for Vo supply. It was enough to replace a couple of resistors to change the mathematical function and adapt the circuit from HD44780 to ST7066. | I have encountered (in an UniOp EK42) an interesting contrast control circuitry, fortunately designed to comprehend wide range for Vo supply. It was enough to replace a couple of resistors to change the mathematical function and adapt the circuit from HD44780 to ST7066. | ||
| - | {{:notes:alim-lcd.png?300|}} | + | {{:notes:alim-lcd.png?500|}} |
| With Vr that is a square wave from an MCU, with period about 10us, variable duty cycle; Vcc=5V, Vee=-5V (about). | With Vr that is a square wave from an MCU, with period about 10us, variable duty cycle; Vcc=5V, Vee=-5V (about). | ||
