TFT_Touch_Shield - Library files for using Seeed Studio TFT Touch Sh…

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Elmicro Computer / Mbed 2 deprecated TFT_Touch_Shield

Library files for using Seeed Studio TFT Touch Shield for Arduino (ST7781R controller) together with ELMICRO TestBed for mbed. Featuring a short example program of how to calibrate the touch screen. Some basic drawing functions are also included (circle, rectangle, lines, text).

Dependencies: mbed

touch.cpp@0:db0d63650413, 2012-06-28 (annotated)

Committer:: elmicro
Date:: Thu Jun 28 10:12:07 2012 +0000
Revision:: 0:db0d63650413

Who changed what in which revision?

User	Revision	Line number	New contents of line
elmicro	0:db0d63650413	1	#include <LPC17xx.h>
elmicro	0:db0d63650413	2	#include "touch.h"
elmicro	0:db0d63650413	3	#include "shortcuts.h"
elmicro	0:db0d63650413	4
elmicro	0:db0d63650413	5	struct tinit TFTData;
elmicro	0:db0d63650413	6
elmicro	0:db0d63650413	7	void TouchInit(void)
elmicro	0:db0d63650413	8	{
elmicro	0:db0d63650413	9	LPC_SC->PCONP \|= (BIT12); //Enable power to ADC block
elmicro	0:db0d63650413	10	LPC_ADC->ADCR = BIT8 \| //ADC clock is (25MHz/5)
elmicro	0:db0d63650413	11	BIT21; //enable ADC
elmicro	0:db0d63650413	12	}
elmicro	0:db0d63650413	13
elmicro	0:db0d63650413	14	/* ===================================================================
elmicro	0:db0d63650413	15	routine: GetPressure
elmicro	0:db0d63650413	16	purpose: Hardware driver for sampling the touch screen using
elmicro	0:db0d63650413	17	four ADC-channels
elmicro	0:db0d63650413	18	parameters: none
elmicro	0:db0d63650413	19	returns: raw value from ADC corresponding to pressure of
elmicro	0:db0d63650413	20	touch input
elmicro	0:db0d63650413	21	note: "Pressure" actually means how much display area is
elmicro	0:db0d63650413	22	supposed to pressure
elmicro	0:db0d63650413	23	date: 2012-06-27
elmicro	0:db0d63650413	24	author: Stefan Guenther
elmicro	0:db0d63650413	25	Elektronikladen \| ELMICRO
elmicro	0:db0d63650413	26	-------------------------------------------------------------------*/
elmicro	0:db0d63650413	27	unsigned int GetPressure(void)
elmicro	0:db0d63650413	28	{
elmicro	0:db0d63650413	29	int tmp;
elmicro	0:db0d63650413	30
elmicro	0:db0d63650413	31	LPC_PINCON->PINSEL1 &= ~0x4000; //Y-
elmicro	0:db0d63650413	32	LPC_PINCON->PINSEL1 \|= 0x10000; //X-
elmicro	0:db0d63650413	33	LPC_PINCON->PINSEL1 \|= 0x40000; //Y+
elmicro	0:db0d63650413	34	LPC_PINCON->PINSEL1 &= ~0x100000; //X+
elmicro	0:db0d63650413	35	LPC_GPIO0->FIODIR \|= BIT23\|BIT26; //X- and Y+ as output
elmicro	0:db0d63650413	36	LPC_GPIO0->FIOCLR = BIT23; //X- is GND
elmicro	0:db0d63650413	37	LPC_GPIO0->FIOSET = BIT26; //Y+ is VCC (3V3)
elmicro	0:db0d63650413	38	LPC_ADC->ADCR &= ~0xFF;
elmicro	0:db0d63650413	39	LPC_ADC->ADCR \|= BIT1; //set X- as ADC input
elmicro	0:db0d63650413	40	LPC_ADC->ADCR \|= BIT24; //start sampling
elmicro	0:db0d63650413	41	while(!(LPC_ADC->ADGDR&BIT31)); //wait for ADC
elmicro	0:db0d63650413	42
elmicro	0:db0d63650413	43	tmp = (LPC_ADC->ADGDR&0xFFF0)>>4; //store ADC value
elmicro	0:db0d63650413	44	LPC_ADC->ADCR &= ~0xFF;
elmicro	0:db0d63650413	45	LPC_ADC->ADCR \|= BIT2; //set Y+ as ADC input
elmicro	0:db0d63650413	46	LPC_ADC->ADCR \|= BIT24; //start another ADC sampling
elmicro	0:db0d63650413	47	while(!(LPC_ADC->ADGDR&BIT31)); //wait for it
elmicro	0:db0d63650413	48
elmicro	0:db0d63650413	49	//calculate pressure value out of the two samples
elmicro	0:db0d63650413	50	//and invert it by subtracting from 2^12
elmicro	0:db0d63650413	51	return(4096 - (tmp - ( (LPC_ADC->ADGDR&0xFFF0) >>4 ) ) );
elmicro	0:db0d63650413	52	}
elmicro	0:db0d63650413	53
elmicro	0:db0d63650413	54
elmicro	0:db0d63650413	55	/* ===================================================================
elmicro	0:db0d63650413	56	routine: GetTouchX
elmicro	0:db0d63650413	57	purpose: Hardware driver for sampling the touch screen using
elmicro	0:db0d63650413	58	four ADC-channels
elmicro	0:db0d63650413	59	parameters: none
elmicro	0:db0d63650413	60	returns: raw value from ADC corresponding to X coordinate of
elmicro	0:db0d63650413	61	touch input
elmicro	0:db0d63650413	62	date: 2012-06-27
elmicro	0:db0d63650413	63	author: Stefan Guenther
elmicro	0:db0d63650413	64	Elektronikladen \| ELMICRO
elmicro	0:db0d63650413	65	-------------------------------------------------------------------*/
elmicro	0:db0d63650413	66	unsigned int GetTouchX(void)
elmicro	0:db0d63650413	67	{
elmicro	0:db0d63650413	68	LPC_PINCON->PINSEL1 \|= 0x4000; //connects to Y- signal
elmicro	0:db0d63650413	69	LPC_PINCON->PINSEL1 &= ~0x10000; // X-
elmicro	0:db0d63650413	70	LPC_PINCON->PINSEL1 \|= 0x40000; // Y+
elmicro	0:db0d63650413	71	LPC_PINCON->PINSEL1 &= ~0x100000; // X+
elmicro	0:db0d63650413	72	LPC_GPIO0->FIODIR \|= BIT24\|BIT26; //X+ and X- as output
elmicro	0:db0d63650413	73	LPC_GPIO0->FIOCLR = BIT24; //X- set to GND
elmicro	0:db0d63650413	74	LPC_GPIO0->FIOSET = BIT26; //X+ set to VCC (3V3)
elmicro	0:db0d63650413	75	LPC_ADC->ADCR &= ~0xFF; //clear active ADC channel information
elmicro	0:db0d63650413	76	LPC_ADC->ADCR \|= BIT2; //set Y- as active ADC channel
elmicro	0:db0d63650413	77	LPC_ADC->ADCR \|= BIT24; //start ADC sampling
elmicro	0:db0d63650413	78	while(!(LPC_ADC->ADGDR&BIT31)); //wait until ADC completes operation
elmicro	0:db0d63650413	79
elmicro	0:db0d63650413	80	return((LPC_ADC->ADGDR&0xFFF0)>>4); //extract the 12bit-information
elmicro	0:db0d63650413	81	}
elmicro	0:db0d63650413	82
elmicro	0:db0d63650413	83
elmicro	0:db0d63650413	84	/* ===================================================================
elmicro	0:db0d63650413	85	routine: GetTouchY
elmicro	0:db0d63650413	86	purpose: Hardware driver for sampling the touch screen using
elmicro	0:db0d63650413	87	four ADC-channels
elmicro	0:db0d63650413	88	parameters: none
elmicro	0:db0d63650413	89	returns: raw value from ADC corresponding to Y coordinate of
elmicro	0:db0d63650413	90	touch input
elmicro	0:db0d63650413	91	date: 2012-06-27
elmicro	0:db0d63650413	92	author: Stefan Guenther
elmicro	0:db0d63650413	93	Elektronikladen \| ELMICRO
elmicro	0:db0d63650413	94	-------------------------------------------------------------------*/
elmicro	0:db0d63650413	95	unsigned int GetTouchY(void)
elmicro	0:db0d63650413	96	{
elmicro	0:db0d63650413	97	LPC_PINCON->PINSEL1 &= ~0x4000; //Y-
elmicro	0:db0d63650413	98	LPC_PINCON->PINSEL1 \|= 0x10000; //X-
elmicro	0:db0d63650413	99	LPC_PINCON->PINSEL1 &= ~0x40000; //Y+
elmicro	0:db0d63650413	100	LPC_PINCON->PINSEL1 \|= 0x100000; //X+
elmicro	0:db0d63650413	101	LPC_GPIO0->FIODIR \|= BIT23\|BIT25; //Y+ and Y- as output
elmicro	0:db0d63650413	102	LPC_GPIO0->FIOCLR = BIT23;
elmicro	0:db0d63650413	103	LPC_GPIO0->FIOSET = BIT25;
elmicro	0:db0d63650413	104	LPC_ADC->ADCR &= ~0xFF;
elmicro	0:db0d63650413	105	LPC_ADC->ADCR \|= BIT3;
elmicro	0:db0d63650413	106	LPC_ADC->ADCR \|= BIT24;
elmicro	0:db0d63650413	107	while(!(LPC_ADC->ADGDR&BIT31));
elmicro	0:db0d63650413	108
elmicro	0:db0d63650413	109	return((LPC_ADC->ADGDR&0xFFF0)>>4);
elmicro	0:db0d63650413	110	}
elmicro	0:db0d63650413	111
elmicro	0:db0d63650413	112
elmicro	0:db0d63650413	113	/* ===================================================================
elmicro	0:db0d63650413	114	routine: GetRawTouch
elmicro	0:db0d63650413	115	purpose: Reads input values from Touchscreen without
elmicro	0:db0d63650413	116	processing them (mainly useful for doing a calibration)
elmicro	0:db0d63650413	117	parameters: <*x,y,z> pointers to coordinate variables
elmicro	0:db0d63650413	118	returns: 1 if touch was recognized
elmicro	0:db0d63650413	119	0 if no touch occured
elmicro	0:db0d63650413	120	note: For code explanation, look the GetPoint() function
elmicro	0:db0d63650413	121	date: 2012-06-27
elmicro	0:db0d63650413	122	author: Stefan Guenther
elmicro	0:db0d63650413	123	Elektronikladen \| ELMICRO
elmicro	0:db0d63650413	124	-------------------------------------------------------------------*/
elmicro	0:db0d63650413	125	unsigned char GetRawTouch(unsigned int x, unsigned int y, unsigned int *z)
elmicro	0:db0d63650413	126	{
elmicro	0:db0d63650413	127	unsigned int x1, x2, y1, y2, z1, z2;
elmicro	0:db0d63650413	128
elmicro	0:db0d63650413	129	z1 = GetPressure();
elmicro	0:db0d63650413	130
elmicro	0:db0d63650413	131	if(z1>1500)
elmicro	0:db0d63650413	132	{
elmicro	0:db0d63650413	133	x1 = GetTouchX();
elmicro	0:db0d63650413	134	y1 = GetTouchY();
elmicro	0:db0d63650413	135
elmicro	0:db0d63650413	136	z2 = GetPressure();
elmicro	0:db0d63650413	137	if(z2>1500)
elmicro	0:db0d63650413	138	{
elmicro	0:db0d63650413	139	x2 = GetTouchX();
elmicro	0:db0d63650413	140	y2 = GetTouchY();
elmicro	0:db0d63650413	141
elmicro	0:db0d63650413	142	if( ( (x1>x2-20) && (x1<x2+20) ) && ( (y1>y2-20) && (y1<y2+20) ) )
elmicro	0:db0d63650413	143	{
elmicro	0:db0d63650413	144	*x = (x1+x2) / 2;
elmicro	0:db0d63650413	145	*y = (y1+y2) / 2;
elmicro	0:db0d63650413	146	*z = (z1+z2) / 2;
elmicro	0:db0d63650413	147
elmicro	0:db0d63650413	148	return 1;
elmicro	0:db0d63650413	149	}
elmicro	0:db0d63650413	150	}
elmicro	0:db0d63650413	151	}
elmicro	0:db0d63650413	152	return 0;
elmicro	0:db0d63650413	153	}
elmicro	0:db0d63650413	154
elmicro	0:db0d63650413	155
elmicro	0:db0d63650413	156	/* ===================================================================
elmicro	0:db0d63650413	157	routine: MapX
elmicro	0:db0d63650413	158	purpose: Maps/alligns X-coordinate of touch input onto LCD's
elmicro	0:db0d63650413	159	pixel grid
elmicro	0:db0d63650413	160	parameters: <x> touch coordinate
elmicro	0:db0d63650413	161	returns: pixel coordinate of touch input
elmicro	0:db0d63650413	162	date: 2012-06-27
elmicro	0:db0d63650413	163	author: Stefan Guenther
elmicro	0:db0d63650413	164	Elektronikladen \| ELMICRO
elmicro	0:db0d63650413	165	-------------------------------------------------------------------*/
elmicro	0:db0d63650413	166	unsigned int MapX(unsigned int x)
elmicro	0:db0d63650413	167	{
elmicro	0:db0d63650413	168	if(x>TFTData.Xmin)
elmicro	0:db0d63650413	169	{
elmicro	0:db0d63650413	170	x = x-TFTData.Xmin;
elmicro	0:db0d63650413	171	x = (x*1000) / TFTData.Xscale;
elmicro	0:db0d63650413	172	if(x>TFTData.XRes - 1) x = TFTData.XRes - 1;
elmicro	0:db0d63650413	173	} else {
elmicro	0:db0d63650413	174	x = 0;
elmicro	0:db0d63650413	175	}
elmicro	0:db0d63650413	176	return x;
elmicro	0:db0d63650413	177	}
elmicro	0:db0d63650413	178
elmicro	0:db0d63650413	179
elmicro	0:db0d63650413	180	/* ===================================================================
elmicro	0:db0d63650413	181	routine: MapY
elmicro	0:db0d63650413	182	purpose: Maps/alligns Y-coordinate of touch input onto LCD's
elmicro	0:db0d63650413	183	pixel grid
elmicro	0:db0d63650413	184	parameters: <x> touch coordinate
elmicro	0:db0d63650413	185	returns: pixel coordinate of touch input
elmicro	0:db0d63650413	186	date: 2012-06-27
elmicro	0:db0d63650413	187	author: Stefan Guenther
elmicro	0:db0d63650413	188	Elektronikladen \| ELMICRO
elmicro	0:db0d63650413	189	-------------------------------------------------------------------*/
elmicro	0:db0d63650413	190	unsigned int MapY(unsigned int y)
elmicro	0:db0d63650413	191	{
elmicro	0:db0d63650413	192	if(y>TFTData.Ymin) //Y input larger than the expected minimum?
elmicro	0:db0d63650413	193	{
elmicro	0:db0d63650413	194	y = y - TFTData.Ymin; //subtract offset from Y coordinate
elmicro	0:db0d63650413	195	y = (y*1000) / TFTData.Yscale; //scale according to touch screen's parameter
elmicro	0:db0d63650413	196	//(this results in an alignment between touch
elmicro	0:db0d63650413	197	//input and output pixel grid)
elmicro	0:db0d63650413	198	if(y>TFTData.YRes - 1) y = TFTData.YRes - 1; //prevent "out of pixel boundary"
elmicro	0:db0d63650413	199	} else {
elmicro	0:db0d63650413	200	y = 0; //sampled Y-coordinate was lower than touch
elmicro	0:db0d63650413	201	} //screen's expected minimum, so keep Y in boundary
elmicro	0:db0d63650413	202	return y;
elmicro	0:db0d63650413	203	}
elmicro	0:db0d63650413	204
elmicro	0:db0d63650413	205
elmicro	0:db0d63650413	206	/* ===================================================================
elmicro	0:db0d63650413	207	routine: GetPoint
elmicro	0:db0d63650413	208	purpose: Reads and processes touch input
elmicro	0:db0d63650413	209	parameters: <x, y> pointers to coordinate variables
elmicro	0:db0d63650413	210	returns: 1 if touch input was recognized
elmicro	0:db0d63650413	211	0 if no touch occured
elmicro	0:db0d63650413	212
elmicro	0:db0d63650413	213	note: An oversampling (x2) is done to increase noise
elmicro	0:db0d63650413	214	immunity.
elmicro	0:db0d63650413	215	A pressure value of 1500 has to be read to trigger
elmicro	0:db0d63650413	216	the further processing - a lower value could improve
elmicro	0:db0d63650413	217	touch sensitivity but also increases the risk of
elmicro	0:db0d63650413	218	sampling noise instead of touch inputs.
elmicro	0:db0d63650413	219	date: 2012-06-27
elmicro	0:db0d63650413	220	author: Stefan Guenther
elmicro	0:db0d63650413	221	Elektronikladen \| ELMICRO
elmicro	0:db0d63650413	222	-------------------------------------------------------------------*/
elmicro	0:db0d63650413	223	unsigned char GetPoint(unsigned int x, unsigned int y)
elmicro	0:db0d63650413	224	{
elmicro	0:db0d63650413	225	unsigned int x1, x2, y1, y2, z1, z2;
elmicro	0:db0d63650413	226
elmicro	0:db0d63650413	227	z1 = GetPressure(); //check for pressure onto touch screen
elmicro	0:db0d63650413	228	if(z1>1500) //pressure above threshold?
elmicro	0:db0d63650413	229	{
elmicro	0:db0d63650413	230	x1 = MapX(GetTouchX()); //read touch coordinates
elmicro	0:db0d63650413	231	y1 = MapY(GetTouchY());
elmicro	0:db0d63650413	232
elmicro	0:db0d63650413	233	z2 = GetPressure(); //oversampling - start second input read
elmicro	0:db0d63650413	234	if(z2>1500) //the second pressure was also above threshold?
elmicro	0:db0d63650413	235	{
elmicro	0:db0d63650413	236	x2 = MapX(GetTouchX()); //sample again
elmicro	0:db0d63650413	237	y2 = MapY(GetTouchY());
elmicro	0:db0d63650413	238
elmicro	0:db0d63650413	239	/* check if both samples were nearly the same
elmicro	0:db0d63650413	240	increase the '2' to improve sensitivity */
elmicro	0:db0d63650413	241	if( ( (x1>x2 - 2) && (x1<x2+2) ) && ( (y1>y2 - 2) && (y1<y2 + 2) ) )
elmicro	0:db0d63650413	242	{
elmicro	0:db0d63650413	243	*x = (x1+x2) / 2; //do a simple meridian calculation
elmicro	0:db0d63650413	244	*y = (y1+y2) / 2; //on both samples and both coordinates
elmicro	0:db0d63650413	245
elmicro	0:db0d63650413	246	return 1; //touch input was processed!
elmicro	0:db0d63650413	247	}
elmicro	0:db0d63650413	248	}
elmicro	0:db0d63650413	249	}
elmicro	0:db0d63650413	250	return 0; //no touch input was processed!
elmicro	0:db0d63650413	251	}

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	27 Jun 2012
Imports:	464
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	1
Followers:	13

touch.cpp@0:db0d63650413, 2012-06-28 (annotated)

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