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+====== SPI ======
+{{http://dn.odroid.com/wiki_image/IMG_20150805_163924.jpg?500|}}
+=== How to use SPI ===
+<code>
+root@odroid:~# lsmod
+Module                  Size  Used by
+uinput                  6669  1
+ir_lirc_codec           4243  3
+lirc_dev               10110  1 ir_lirc_codec
+ir_mce_kbd_decoder      3092  0
+ir_sanyo_decoder        1638  0
+ir_sony_decoder         1667  0
+ir_jvc_decoder          1664  0
+ir_rc6_decoder          2024  0
+ir_rc5_decoder          1552  0
+ir_nec_decoder          1776  0
+meson_ir                2902  0
+joydev                  8607  0
+hid_logitech_dj        11642  0
+fuse                   70879  2
+nls_cp437               5125  1
+</code>
+<code>
+root@odroid:~# modprobe spicc
+</code>
+<code>
+root@odroid:~# lsmod
+Module                  Size  Used by
+ads7846                13766  0
+spidev                  5465  0
+spicc                   7846  0
+uinput                  6669  1
+ir_lirc_codec           4243  3
+lirc_dev               10110  1 ir_lirc_codec
+ir_mce_kbd_decoder      3092  0
+ir_sanyo_decoder        1638  0
+ir_sony_decoder         1667  0
+ir_jvc_decoder          1664  0
+ir_rc6_decoder          2024  0
+ir_rc5_decoder          1552  0
+ir_nec_decoder          1776  0
+meson_ir                2902  0
+joydev                  8607  0
+hid_logitech_dj        11642  0
+fuse                   70879  2
+nls_cp437               5125  1
+</code>
+<code>
+root@odroid:~# ls /dev/spidev0.0
+/dev/spidev0.0
+root@odroid:~#
+</code>
+=== Compile & run SPI test example source code ===
+  gcc -o spidev_test spidev_test.c
+<code>
+odroid@odroid:~$ ./spidev_test
+spi mode: 0
+bits per word: 8
+max speed: 500000 Hz (500 KHz)
+</code>
+<file c spidev_test.c>
+/*
+ * SPI testing utility (using spidev driver)
+ *
+ * Copyright (c) 2007  MontaVista Software, Inc.
+ * Copyright (c) 2007  Anton Vorontsov <avorontsov@ru.mvista.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License.
+ *
+ * Cross-compile with cross-gcc -I/path/to/cross-kernel/include
+ */
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <linux/spi/spidev.h>
+#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
+#define uchar unsigned char
+#define MAX_RAW     36
+#define MAX_COLUMN  8
+uchar disp1[MAX_RAW][MAX_COLUMN] = {
+    {0x3C,0x42,0x42,0x42,0x42,0x42,0x42,0x3C},//0
+    {0x10,0x30,0x50,0x10,0x10,0x10,0x10,0x7C},//1
+    {0x3E,0x02,0x02,0x3E,0x20,0x20,0x3E,0x00},//2
+    {0x00,0x7C,0x04,0x04,0x7C,0x04,0x04,0x7C},//3
+    {0x08,0x18,0x28,0x48,0xFE,0x08,0x08,0x08},//4
+    {0x3C,0x20,0x20,0x3C,0x04,0x04,0x3C,0x00},//5
+    {0x3C,0x20,0x20,0x3C,0x24,0x24,0x3C,0x00},//6
+    {0x3E,0x22,0x04,0x08,0x08,0x08,0x08,0x08},//7
+    {0x00,0x3E,0x22,0x22,0x3E,0x22,0x22,0x3E},//8
+    {0x3E,0x22,0x22,0x3E,0x02,0x02,0x02,0x3E},//9
+    {0x08,0x14,0x22,0x3E,0x22,0x22,0x22,0x22},//A
+    {0x3C,0x22,0x22,0x3E,0x22,0x22,0x3C,0x00},//B
+    {0x3C,0x40,0x40,0x40,0x40,0x40,0x3C,0x00},//C
+    {0x7C,0x42,0x42,0x42,0x42,0x42,0x7C,0x00},//D
+    {0x7C,0x40,0x40,0x7C,0x40,0x40,0x40,0x7C},//E
+    {0x7C,0x40,0x40,0x7C,0x40,0x40,0x40,0x40},//F
+    {0x3C,0x40,0x40,0x40,0x40,0x44,0x44,0x3C},//G
+    {0x44,0x44,0x44,0x7C,0x44,0x44,0x44,0x44},//H
+    {0x7C,0x10,0x10,0x10,0x10,0x10,0x10,0x7C},//I
+    {0x3C,0x08,0x08,0x08,0x08,0x08,0x48,0x30},//J
+    {0x00,0x24,0x28,0x30,0x20,0x30,0x28,0x24},//K
+    {0x40,0x40,0x40,0x40,0x40,0x40,0x40,0x7C},//L
+    {0x81,0xC3,0xA5,0x99,0x81,0x81,0x81,0x81},//M
+    {0x00,0x42,0x62,0x52,0x4A,0x46,0x42,0x00},//N
+    {0x3C,0x42,0x42,0x42,0x42,0x42,0x42,0x3C},//O
+    {0x3C,0x22,0x22,0x22,0x3C,0x20,0x20,0x20},//P
+    {0x1C,0x22,0x22,0x22,0x22,0x26,0x22,0x1D},//Q
+    {0x3C,0x22,0x22,0x22,0x3C,0x24,0x22,0x21},//R
+    {0x00,0x1E,0x20,0x20,0x3E,0x02,0x02,0x3C},//S
+    {0x00,0x3E,0x08,0x08,0x08,0x08,0x08,0x08},//T
+    {0x42,0x42,0x42,0x42,0x42,0x42,0x22,0x1C},//U
+    {0x42,0x42,0x42,0x42,0x42,0x42,0x24,0x18},//V
+    {0x00,0x49,0x49,0x49,0x49,0x2A,0x1C,0x00},//W
+    {0x00,0x41,0x22,0x14,0x08,0x14,0x22,0x41},//X
+    {0x41,0x22,0x14,0x08,0x08,0x08,0x08,0x08},//Y
+    {0x00,0x7F,0x02,0x04,0x08,0x10,0x20,0x7F},//Z
+};
+static void pabort(const char *s) {
+    perror(s);
+    abort();
+}
+static const char *device_spidev0_0 = "/dev/spidev0.0";
+static const char *device_spidev1_0 = "/dev/spidev1.0";
+static uint8_t mode;
+static uint8_t bits = 8;
+static uint32_t speed = 500000;
+static void transfer(int fd, uchar address1, uchar dat1, uchar address2, uchar dat2) {
+    int ret;
+    uint8_t tx[] = {
+        address1, dat1, address2, dat2
+    };
+    uint8_t rx[ARRAY_SIZE(tx)] = {0, };
+    struct spi_ioc_transfer tr;
+    tr.tx_buf = (unsigned long)tx;
+    tr.rx_buf = (unsigned long)rx;
+    tr.len = ARRAY_SIZE(tx);
+    tr.speed_hz = speed;
+    tr.bits_per_word = bits;
+    tr.delay_usecs = 0;
+    tr.cs_change = 0;
+    ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
+    if (ret < 1)
+        pabort("can't send SPI message");
+}
+int main() {
+    uchar i , j;
+    int ret = 0;
+    int fd;
+    fd = open(device_spidev0_0, O_RDWR);
+    if (fd < 0) {
+        printf("can't open /dev/spidev0.0\nTry /dev/spidev1.0\n");
+        fd = open(device_spidev1_0, O_RDWR);
+        if (fd < 0)
+            pabort("can't open /dev/spidev1.0");
+    }
+    /* SPI mode */
+    ret = ioctl(fd, SPI_IOC_WR_MODE, &mode);
+    if (ret == -1)
+        pabort("can't set SPI mode");
+    ret = ioctl(fd, SPI_IOC_RD_MODE, &mode);
+    if (ret == -1)
+        pabort("can't get SPI mode");
+    /* bits per word */
+    ret = ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
+    if (ret == -1)
+        pabort("can't set bits per word");
+    ret = ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits);
+    if (ret == -1)
+        pabort("can't get bits per word");
+    /* max speed hz */
+    ret = ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
+    if (ret == -1)
+        pabort("can't set max speed Hz");
+    ret = ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed);
+    if (ret == -1)
+        pabort("can't get max speed Hz");
+    printf("SPI mode: %d\n", mode);
+    printf("bits per word: %d\n", bits);
+    printf("max speed: %d Hz (%d KHz)\n", speed, speed/1000);
+    transfer(fd, 0x09,0x00,0x09,0x00);
+    transfer(fd, 0x0a,0x03,0x0a,0x03);
+    transfer(fd, 0x0b,0x07,0x0b,0x07);
+    transfer(fd, 0x0c,0x01,0x0c,0x01);
+    transfer(fd, 0x0f,0x00,0x0f,0x00);
+    while (1) {
+        for(j = 0; j < MAX_RAW - 1; j++) {
+            for(i = 1; i < MAX_COLUMN + 1; i++)
+                transfer(fd, i, disp1[j + 1][i - 1], i, disp1[j][i - 1]);
+            usleep(1000000);
+        }
+    }
+    close(fd);
+    return ret;
+}
+</file>