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AT91系列

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如何对AT91微控制器外接 4x4 键盘Interfacing a 4x4 Keyboard to an AT91 Microcontroller
Introduction
This Application Note describes programming techniques implemented on the AT91 ARM-based microcontroller for scanning a 4x4 Keyboard matrix usually found in both consumer and industrial applications for numeric data entry.

AT91 Keyboard interface
In this application, a 4x4 matrix keypad requiring eight Input/Output ports for interfacing is used as an example. Rows are connected to Peripheral Input/Output (PIO) pins configured as output. Columns are connected to PIO pins configured as input with interrupts. In this configuration, four pull-up resistors must be added in order to apply a high level on the corresponding input pins as shown in Figure 1. The corresponding hexadecimal value of the pressed key is sent on four LEDs……
标签:如何微控制器外接键盘
AT91系列
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