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Try some other ways with touch sensing. Linux scheduling isn't fast enough
author Matt Johnston <matt@ucc.asn.au>
date Thu, 03 Jan 2013 20:11:54 +0800
parents dce9f7841696
children
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454:dce9f7841696 455:e12d6d677320
10 10
11 #define BCM2708_PERI_BASE 0x20000000 11 #define BCM2708_PERI_BASE 0x20000000
12 #define GPIO_BASE (BCM2708_PERI_BASE + 0x200000) /* GPIO controller */ 12 #define GPIO_BASE (BCM2708_PERI_BASE + 0x200000) /* GPIO controller */
13 13
14 14
15 // for usleep
16 #define _BSD_SOURCE
17
18 // clock_gettime
19 #define _POSIX_C_SOURCE 199309L
20
15 #include <stdio.h> 21 #include <stdio.h>
16 #include <string.h> 22 #include <string.h>
17 #include <stdlib.h> 23 #include <stdlib.h>
24 #include <stdint.h>
18 #include <dirent.h> 25 #include <dirent.h>
19 #include <fcntl.h> 26 #include <fcntl.h>
20 #include <assert.h> 27 #include <assert.h>
21 #include <sys/mman.h> 28 #include <sys/mman.h>
22 #include <sys/types.h> 29 #include <sys/types.h>
23 #include <sys/stat.h> 30 #include <sys/stat.h>
31 #include <time.h>
32 #include <sched.h>
24 33
25 #include <unistd.h> 34 #include <unistd.h>
26 35
27 #define PAGE_SIZE (4*1024) 36 #define PAGE_SIZE (4*1024)
28 #define BLOCK_SIZE (4*1024) 37 #define BLOCK_SIZE (4*1024)
61 #define TOUCH_IN 24 70 #define TOUCH_IN 24
62 #define TOUCH_OUT 25 71 #define TOUCH_OUT 25
63 72
64 void setup_io(); 73 void setup_io();
65 74
75 static int cmp_int(const void *a, const void *b)
76 {
77 const int *ia = a;
78 const int *ib = b;
79 return (*ia - *ib);
80 }
81
82 static int clock_diff(struct timespec *t1, struct timespec *t2)
83 {
84 uint64_t v1 = t1->tv_sec * 1000000000 + t1->tv_nsec;
85 uint64_t v2 = t2->tv_sec * 1000000000 + t2->tv_nsec;
86 return v2-v1;
87 }
88
66 int main(int argc, char **argv) 89 int main(int argc, char **argv)
67 { 90 {
68 int g,rep; 91 // Set up gpi pointer for direct register access
69 92 setup_io();
70 // Set up gpi pointer for direct register access
71 setup_io();
72
73 // Switch GPIO 7..11 to output mode
74
75 /************************************************************************\
76 * You are about to change the GPIO settings of your computer. *
77 * Mess this up and it will stop working! *
78 * It might be a good idea to 'sync' before running this program *
79 * so at least you still have your code changes written to the SD-card! *
80 \************************************************************************/
81
82 93
83 INP_GPIO(TOUCH_IN); 94 INP_GPIO(TOUCH_IN);
84 INP_GPIO(TOUCH_OUT); 95 INP_GPIO(TOUCH_OUT);
85 OUT_GPIO(TOUCH_OUT); 96 OUT_GPIO(TOUCH_OUT);
86 97
87 int num = 1000; 98 const int num = 200;
88 int sum = 0; 99 const int margin = 30;
100 int print = 0;
101 if (argc > 1)
102 {
103 print = 1;
104 }
89 105
90 while (1) 106 while (1)
91 { 107 {
92 int n; 108 int vals[num];
93 sum = 0; 109 int nsecs[num];
94 for (n = 0; n < num; n++) 110 for (int n = 0; n < num; n++)
95 { 111 {
96 GPIO_CLR(TOUCH_OUT); 112 GPIO_CLR(TOUCH_OUT);
97 usleep(1000); 113 struct timespec t = {.tv_nsec=20};
114 nanosleep(&t, NULL);
115 //sched_yield();
116 //usleep(1);
117 if (GPIO_GET(TOUCH_IN))
118 {
119 printf("short ");
120 }
98 GPIO_SET(TOUCH_OUT); 121 GPIO_SET(TOUCH_OUT);
122 int val = 0;
99 while (GPIO_GET(TOUCH_IN) == 0) 123 while (GPIO_GET(TOUCH_IN) == 0)
100 { 124 {
101 sum++; 125 val++;
102 } 126 }
127
128 vals[n] = val;
103 } 129 }
104 printf("total %f\n", (float)sum / num); 130 qsort(vals, num, sizeof(*vals), cmp_int);
105 } 131 int sum = 0, count = 0;
132 for (int n = 0; n < num; n++)
133 {
134 if (print)
135 {
136 printf("%3d ", vals[n]);
137 if (n == num-1 || n % 10 == 9)
138 {
139 printf("\n");
140 }
141 if (n == margin || n == num-margin)
142 {
143 printf("#");
144 }
145 }
146 if (n >= margin && n < (num-margin))
147 {
148 sum += vals[n];
149 count ++;
150 }
151 }
152 printf("total %f from %d\n", (float)sum / count, count);
153 usleep(500000);
154 }
106 return 0; 155 return 0;
107 156
108 } // main 157 } // main
109 158
110 159
111 // 160 //
112 // Set up a memory regions to access GPIO 161 // Set up a memory regions to access GPIO
113 // 162 //
114 void setup_io() 163 void setup_io()
115 { 164 {
116 /* open /dev/mem */ 165 /* open /dev/mem */
117 if ((mem_fd = open("/dev/mem", O_RDWR|O_SYNC) ) < 0) { 166 if ((mem_fd = open("/dev/mem", O_RDWR|O_SYNC) ) < 0) {
118 printf("can't open /dev/mem \n"); 167 printf("can't open /dev/mem \n");
119 exit (-1); 168 exit (-1);
120 } 169 }
121 170
122 /* mmap GPIO */ 171 /* mmap GPIO */
123 172
124 // Allocate MAP block 173 // Allocate MAP block
125 if ((gpio_mem = malloc(BLOCK_SIZE + (PAGE_SIZE-1))) == NULL) { 174 if ((gpio_mem = malloc(BLOCK_SIZE + (PAGE_SIZE-1))) == NULL) {
126 printf("allocation error \n"); 175 printf("allocation error \n");
127 exit (-1); 176 exit (-1);
128 } 177 }
129 178
130 // Make sure pointer is on 4K boundary 179 // Make sure pointer is on 4K boundary
131 if ((unsigned long)gpio_mem % PAGE_SIZE) 180 if ((unsigned long)gpio_mem % PAGE_SIZE)
132 gpio_mem += PAGE_SIZE - ((unsigned long)gpio_mem % PAGE_SIZE); 181 gpio_mem += PAGE_SIZE - ((unsigned long)gpio_mem % PAGE_SIZE);
133 182
134 // Now map it 183 // Now map it
135 gpio_map = (unsigned char *)mmap( 184 gpio_map = mmap(
136 (caddr_t)gpio_mem, 185 (caddr_t)gpio_mem,
137 BLOCK_SIZE, 186 BLOCK_SIZE,
138 PROT_READ|PROT_WRITE, 187 PROT_READ|PROT_WRITE,
139 MAP_SHARED|MAP_FIXED, 188 MAP_SHARED|MAP_FIXED,
140 mem_fd, 189 mem_fd,
141 GPIO_BASE 190 GPIO_BASE
142 ); 191 );
143 192
144 if ((long)gpio_map < 0) { 193 if ((long)gpio_map < 0) {
145 printf("mmap error %d\n", (int)gpio_map); 194 printf("mmap error %d\n", (int)gpio_map);
146 exit (-1); 195 exit (-1);
147 } 196 }
148 197
149 // Always use volatile pointer! 198 // Always use volatile pointer!
150 gpio = (volatile unsigned *)gpio_map; 199 gpio = (volatile unsigned *)gpio_map;
151 200
152 201
153 } // setup_io 202 } // setup_io