Beaglebone black i2c - Revision history

Heth at 14:49, 29 November 2023

2023-11-29T14:49:09Z

Heth: /* I2C Low level */

2023-11-11T13:05:59Z

‎I2C Low level

Heth: /* I2C Low level */

2023-11-11T13:05:08Z

‎I2C Low level

Heth: /* I2C Low level */

2023-11-11T12:53:40Z

‎I2C Low level

Heth: /* I2C Low level */

2023-11-11T12:48:33Z

‎I2C Low level

Heth: /* I2C Low level */

2023-11-11T10:37:29Z

‎I2C Low level

Heth: /* I2C Low level */

2023-11-11T09:18:03Z

‎I2C Low level

Heth at 09:17, 11 November 2023

2023-11-11T09:17:22Z

Heth at 03:51, 25 May 2023

2023-05-25T03:51:40Z

Heth at 03:46, 25 May 2023

2023-05-25T03:46:57Z

@@ Line 40: / Line 40: @@
+  *
   * REMEMBER: Install the libi2c-dev package to compile this file
-  * Compile this example with: gcc -li2c seeed_dip6.c  -o seeed_dip6
+  * Compile this example with: gcc seeed_dip6.c  -o seeed_dip6  -li2c
   */
 #include <stdio.h>

@@ Line 43: / Line 43: @@
   */
 #include <stdio.h>
 #include <unistd.h>
 #include <sys/ioctl.h>
 #include <stdlib.h>
 #include <errno.h>
 #include <string.h>
 #include <sys/ioctl.h>
 #include <linux/i2c.h>
 #include <linux/i2c-dev.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 //Device specific information. (Perhaps better as command options or config file)

@@ Line 23: / Line 23: @@
 <source lang=c>
   * Module...: seeed_dip6.c
   * Version..: 0.1 (Beta - unfinished)
@@ Line 44: / Line 43: @@
   */
 #include <stdio.h>
 #include <unistd.h>
 #include <sys/ioctl.h>
 #include <stdlib.h>
 #include <errno.h>
 #include <string.h>
 #include <sys/ioctl.h>
 #include <linux/i2c.h>
 #include <linux/i2c-dev.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 //Device specific information. (Perhaps better as command options or config file)
-#define I2C_BUS     "/dev/i2c-2"
+#define I2C_BUS "/dev/i2c-2"
-#define I2C_ADDR        0x03   // Grove DIP-switch 6 slave address default
+#define I2C_ADDR 0x03 // Grove DIP-switch 6 slave address default
-int main( void ) {
+int main(void) {
-        int file;
+  int file;
-                int nmsgs_sent;
+  int nmsgs_sent;
-                unsigned int len;
+  unsigned int len;
-                int i;
+  int i;
-                char buf[2][20];
+  char buf[2][20];
-                struct i2c_msg msgs[I2C_RDRW_IOCTL_MAX_MSGS]; // I2C_RDRW_IOCTL_MAX_MSGS defined in linx/i2c-dev.h
+  struct i2c_msg msgs[I2C_RDRW_IOCTL_MAX_MSGS]; // I2C_RDRW_IOCTL_MAX_MSGS defined in linx/i2c-dev.h
-                struct i2c_rdwr_ioctl_data rdwr;
+  struct i2c_rdwr_ioctl_data rdwr;
-                 // init msgs's
+  // init msgs's
-                for (i = 0; i < I2C_RDRW_IOCTL_MAX_MSGS; i++)
+  for (i = 0; i < I2C_RDRW_IOCTL_MAX_MSGS; i++)
-                msgs[i].buf = NULL;
+    msgs[i].buf = NULL;
-                // Maybe errer just assumes bus number
+  if (file < 0)
-                file = open(I2C_BUS,O_RDWR);
+    fprintf(stderr, "ERROR: open_i2c_dev failed: %s", strerror(errno));
-                if (file < 0)
+  // Build IOCTL operation message structure. (What you want to do)
-                // Build IOCTL operation message structure. (What you want to do)
+  //msgs[0] Write one byte - Command in buf[0] - flags 0 = write
-                //msgs[0] Write one byte - Command in buf[0] - flags 0 = write
+  //msgs[1] read 10 bytes to buf
-                msgs[0].addr = I2C_ADDR;
+  msgs[1].addr = I2C_ADDR;
-                msgs[0].flags = 0;
+  msgs[1].flags = 1;
-                msgs[0].len = 1;
+  msgs[1].len = 10;
-                msgs[0].buf = buf[0];
+  msgs[1].buf = buf[1];
-                //msgs[1] read 10 bytes to buf
+  rdwr.msgs = msgs;
-                msgs[1].addr = I2C_ADDR;
+  rdwr.nmsgs = 2;
-                msgs[1].flags = 1;
+  nmsgs_sent = ioctl(file, I2C_RDWR, & rdwr);
-                msgs[1].len = 10;
+  if (nmsgs_sent != 2) {
-                msgs[1].buf = buf[1];
+    fprintf(stderr, "ERRORi in line %d: Wrong number of messages: %d\n", __LINE__, nmsgs_sent);
+    exit(0);
-−
+  }
-                rdwr.msgs = msgs;
+  for (i = 0; i < 10; i++)
-                rdwr.nmsgs = 2;
+    printf("Read 0x2d: %x\n", buf[1][i]);
-                nmsgs_sent = ioctl(file, I2C_RDWR, &rdwr);
+  return (0);
+}
 </source>

@@ Line 60: / Line 60: @@
 //Device specific information. (Perhaps better as command options or config file)
 #define I2C_BUS     "/dev/i2c-2"
-#define I2C_ADDR        0x10
+#define I2C_ADDR        0x03   // Grove DIP-switch 6 slave address default
 int main( void ) {
@@ Line 86: / Line 86: @@
                          fprintf(stderr,"ERROR: open_i2c_dev failed: %s", strerror(errno));
                  msgs[0].addr = I2C_ADDR;
                  msgs[0].flags = 0;
@@ Line 91: / Line 94: @@
                  msgs[0].buf = buf[0];
                  buf[0][0] = 0x01;
                  msgs[1].addr = I2C_ADDR;
                  msgs[1].flags = 1;
@@ Line 108: / Line 113: @@
          return(0);
+}
 </source>

@@ Line 21: / Line 21: @@
 =I2C Low level=
 See: '''/usr/include/linux/i2c.h''' for ''' i2c_msg''' structure and flags and '''i2c_rdwr_ioctl_data'''
 =I2C device drivers=

@@ Line 19: / Line 19: @@
 *"UU" Means probing was skipped, because a device driver uses the address
 *"Number" - A n i2c device was found
 =I2C device drivers=

← Older revision		Revision as of 03:51, 25 May 2023
Line 25:		Line 25:
	*[https://www.kernel.org/doc/html/latest/i2c/writing-clients.html Implementing I2C device drivers]		*[https://www.kernel.org/doc/html/latest/i2c/writing-clients.html Implementing I2C device drivers]

−	[[Category:Beagleboard Black]][[Category:~~i2c~~]][[Category:Linux]]	+	[[Category:Beagleboard Black]][[Category:I2C]][[Category:Linux]]

@@ Line 21: / Line 21: @@
 =I2C device drivers=
 *[https://www.kernel.org/doc/Documentation/i2c/dev-interface i2c dev-interface] (Must read i2c or SM-bus)
 *[https://www.kernel.org/doc/html/latest/i2c/writing-clients.html Implementing I2C device drivers]
 [[Category:Beagleboard Black]][[Category:i2c]][[Category:Linux]]