MAX1233/MAX1234触摸屏控制器入门

时间：03-17 来源：互联网点击：

DEMO1234 Command	Action	SPI data in	Verification
	Optional: connect oscilloscope to PENIRQ-bar
I C 1 3	Configure PENIRQ-bar pulse accumulator: falling-edge trigger
I 0 1	Reset the pulse accumulator
I R 1	Read the number of times PENIRQ-bar has pulsed low		count = 0
T W AC 8bff	Wait for touch, then scan X,Y,Z1,Z2	0x0040 0x8bff
	Touch the touch screen		PENIRQ pulse
I R 1	Read the number of times PENIRQ-bar has pulsed low		count has increased
T R P	Read X,Y,Z1,Z2 conversion results	0x8000 0x0000 0x8001 0x0000 0x8002 0x0000 0x8003 0x0000
	Touch the touch screen		PENIRQ pulse
I R 1	Read the number of times PENIRQ-bar has pulsed low		count has increased
T R P	Read X,Y,Z1,Z2 conversion results	0x8000 0x0000 0x8001 0x0000 0x8002 0x0000 0x8003 0x0000
	Touch the touch screen		PENIRQ pulse
I R 1	Read the number of times PENIRQ-bar has pulsed low		count has increased
T R P	Read X,Y,Z1,Z2 conversion results	0x8000 0x0000 0x8001 0x0000 0x8002 0x0000 0x8003 0x0000

4) 键盘和通用输入/输出引脚

下面的例子介绍了怎样使用DEMO1234.EXE程序来扫描键盘，怎样使用GPIO键盘扫描引脚。

GPIO控制寄存器将每个C1–C4和R1–R4引脚分别配置为输入、输出或者是键盘的一部分(请参考MAX1233/MAX1234数据资料的表26和表27)。此外，写入GPIO上拉禁止寄存器，将输出引脚配置为开漏输出。

表14. 键盘和GPIO配置实例

DEMO1234 Command	Action	SPI data in
T W GC FFFF	Keypad: none; GPIO outputs: C4,C3,C2,C1,R4,R3,R2,R1; GPIO inputs: none	0x004f 0xffff
T W GC FF00	Keypad: none; GPIO outputs: none; GPIO inputs: C4,C3,C2,C1,R4,R3,R2,R1	0x004f 0xff00
T W GC 0000	Keypad: (C4,C3,C2,C1) x (R4,R3,R2,R1); GPIO outputs: none; GPIO inputs: none	0x004f 0x0000
T W GC C8C0	Keypad: (C2,C1) x (R3,R2,R1); GPIO outputs: C4,C3; GPIO input: R4	0x004f 0xc8c0
T W GP 4000	GPIO pullup disable: C3	0x004e 0x4000

GPIO数据寄存器读取GPIO输入引脚，写入GPIO输出引脚。注意：在这些例子中，C3、C4和R4是引脚名称，而不是元件名称。

表15. GPIO实例

DEMO1234 Command	Action	SPI data in	Verification
T W GC C8C0	Keypad: (C2,C1) x (R3,R2,R1); GPIO outputs: C4,C3; GPIO input: R4	0x004f 0xc8c0
T W GP 4000	GPIO pullup disable: C3	0x004e 0x4000
	Connect external resistor between C3 pin and DVDD
	Connect DVM to C4 pin
T W GD 8000	GPIO write C4 = 1	0x000f 0x8000	C4 pin = high
T W GD 0000	GPIO write C4 = 0	0x000f 0x0000	C4 pin = low
T W GD 8000	GPIO write C4 = 1	0x000f 0x8000	C4 pin = high
T W GD 0000	GPIO write C4 = 0	0x000f 0x0000	C4 pin = low
	Connect DVM to C3 pin
T W GD 4000	GPIO write C3 = 1	0x000f 0x4000	C3 pin = high
T W GD 0000	GPIO write C3 = 0	0x000f 0x0000	C3 pin = low
T W GD 4000	GPIO write C3 = 1	0x000f 0x4000	C3 pin = high
T W GD 0000	GPIO write C3 = 0	0x000f 0x0000	C3 pin = low
	Connect R4 pin to DVDD
T R GD	GPIO read	0x800f 0x0000	Buffer = 0x0800
	Connect R4 pin to GND
T R GD	GPIO read	0x800f 0x0000	Buffer = 0x0000

可以配置键盘控制寄存器在探测到有按键按下时，自动扫描键盘。

表16. 按键命令序列：自动扫描

DEMO1234 Command	Action	SPI data in	Verification
	Optional: connect oscilloscope to KEYIRQ-bar
I C 0 3	Configure KEYIRQ-bar pulse accumulator: falling-edge trigger
I 0 0	Reset the pulse accumulator
I R 0	Read the number of times KEYIRQ-bar has pulsed low		count = 0
T W GC 0000	Keypad: (C4,C3,C2,C1) x (R4,R3,R2,R1); GPIO outputs: none; GPIO inputs: none	0x004f 0x0000
T W KC bf00	Wait for keypress; maximum debounce and hold times	0x0041 0xbf00
	Press and release R1C1 (key "1")		KEYIRQ pulse
I R 0	Read the number of times KEYIRQ-bar has pulsed low		count has increased
T R KB	Read raw keypad result	0x8004 0x0000	0x0001 = R1C1 key
	Press and release R2C2 (key "5")		KEYIRQ pulse
I R 0	Read the number of times KEYIRQ-bar has pulsed low		count has increased
T R KB	Read raw keypad result	0x8004 0x0000	0x0020 = R2C2 key
	Press and release R3C2 (key "8")		KEYIRQ pulse
I R 0	Read the number of times KEYIRQ-bar has pulsed low		count has increased

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