摘要：除了减少所需的GPIO线从十一点到两个数量，该电路还提供了可编程的对比度和背光控制。Maxim > App Notes > Display Drivers Keywords: LCD driver, op amp, I/O port expander, contrast control, backlight-intensity control, digital-to- Nov 23, 2005 analog converter, DAC APPLICATION NOTE 3658 Serializing an HD44780 LCD Display Abstract: Besides reducing the number of required GPIO lines from eleven to two, this circuit also provides programmable contrast and backlight control. Most LCD character displays connect to the outside world through a controller IC, such as the HD44780 (Hitachi) or equivalent. That interface has serious drawbacks, however. It uses up a large number of the microcontroller's general-purpose input/output (GPIO) pins, and it isn't capable of providing digital-contrast or backlight-intensity control. The circuit in Figure 1 reduces the required number o……