Merge pull request #4782 from haukepetersen/add_srf02_addrconf

drivers/srf02: made device address reprogrammable

drivers/include/srf02.h

@@ -34,7 +34,7 @@ extern "C" {
 /**
  * @brief   Default I2C address of SRF02 sensors
  */
-#define SRF02_DEFAULT_ADDR                  112
+#define SRF02_DEFAULT_ADDR                  (0xe0)
 
 /**
  * @brief   Device descriptor for SRF02 sensors
@@ -85,6 +85,14 @@ int srf02_init(srf02_t *dev, i2c_t i2c, uint8_t addr);
  */
 uint16_t srf02_get_distance(srf02_t *dev, srf02_mode_t mode);
 
+/**
+ * @brief   Program the given device with a new bus address
+ *
+ * @param[in] dev           device to program
+ * @param[in] new_addr      new address to program the given device to
+ */
+void srf02_set_addr(srf02_t *dev, uint8_t new_addr);
+
 #ifdef __cplusplus
 }
 #endif

drivers/srf02/srf02.c

@@ -28,7 +28,7 @@
 #include "srf02.h"
 #include "periph/i2c.h"
 
-#define ENABLE_DEBUG (0)
+#define ENABLE_DEBUG        (0)
 #include "debug.h"
 
 /**
@@ -52,10 +52,20 @@
 #define REG_AUTO_LOW        (0x05)
 /** @} */
 
+/**
+ * @brief   Some additional SRF02 commands
+ * @{
+ */
+#define CMD_ADDR_SEQ1       (0xa0)
+#define CMD_ADDR_SEQ2       (0xaa)
+#define CMD_ADDR_SEQ3       (0xa5)
+/** @} */
+
+
 int srf02_init(srf02_t *dev, i2c_t i2c, uint8_t addr)
 {
     dev->i2c = i2c;
-    dev->addr = addr;
+    dev->addr = (addr >> 1);    /* internally we right align the 7-bit addr */
     char rev;
 
     /* Acquire exclusive access to the bus. */
@@ -66,7 +76,7 @@ int srf02_init(srf02_t *dev, i2c_t i2c, uint8_t addr)
         return -1;
     }
     /* try to read the software revision (read the CMD reg) from the device */
-    i2c_read_reg(i2c, addr, REG_CMD, &rev);
+    i2c_read_reg(i2c, dev->addr, REG_CMD, &rev);
     if (rev == 0 || rev == 255) {
         DEBUG("[srf02] error reading the devices software revision\n");
         return -1;
@@ -102,3 +112,21 @@ uint16_t srf02_get_distance(srf02_t *dev, srf02_mode_t mode)
     /* compile result - TODO: fix for different host byte order other than LE */
     return ((((uint16_t)res[0]) << 8) | (res[1] & 0xff));
 }
+
+void srf02_set_addr(srf02_t *dev, uint8_t new_addr)
+{
+    /* get access to the bus */
+    i2c_acquire(dev->i2c);
+
+    DEBUG("[srf02] reprogramming device address to 0x%02x\n", (int)new_addr);
+
+    /* write the new address, for this we need to follow a certain sequence */
+    i2c_write_reg(dev->i2c, dev->addr, REG_CMD, CMD_ADDR_SEQ1);
+    i2c_write_reg(dev->i2c, dev->addr, REG_CMD, CMD_ADDR_SEQ2);
+    i2c_write_reg(dev->i2c, dev->addr, REG_CMD, CMD_ADDR_SEQ3);
+    i2c_write_reg(dev->i2c, dev->addr, REG_CMD, new_addr);
+    dev->addr = (new_addr >> 1);
+
+    /* release the bus */
+    i2c_release(dev->i2c);
+}

tests/driver_srf02/Makefile

@@ -5,6 +5,7 @@ FEATURES_REQUIRED = periph_i2c
 
 USEMODULE += xtimer
 USEMODULE += srf02
+USEMODULE += shell
 
 # set default device parameters in case they are undefined
 TEST_SRF02_I2C ?= I2C_0

tests/driver_srf02/main.c

@@ -21,6 +21,14 @@
  * @}
  */
 
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "shell.h"
+#include "xtimer.h"
+#include "srf02.h"
+
 #ifndef TEST_SRF02_I2C
 #error "TEST_SRF02_I2C not defined"
 #endif
@@ -28,26 +36,35 @@
 #error "TEST_MODE not defined"
 #endif
 
-#include <stdio.h>
+#define SAMPLE_PERIOD       (100 * 1000U)
 
-#include "xtimer.h"
-#include "srf02.h"
-#include "periph/i2c.h"
+static srf02_t dev;
 
-#define SAMPLE_PERIOD       (1000 * 1000U)
-
-int main(void)
+static void sample_loop(void)
 {
-    int res;
-    srf02_t dev;
     uint32_t wakeup = xtimer_now();
 
-    puts("\nSRF02 Ultrasonic Range Sensor Test\n");
-    puts("This test will sample the sensor once per second and display the\n"
-         "result\n");
+    while(1) {
+        uint16_t distance = srf02_get_distance(&dev, TEST_MODE);
+        printf("distance = %3i cm\n", distance);
+        xtimer_usleep_until(&wakeup, SAMPLE_PERIOD);
+    }
+}
 
-    printf("Initializing SRF02 sensor at I2C_%i... ", TEST_SRF02_I2C);
-    res = srf02_init(&dev, TEST_SRF02_I2C, SRF02_DEFAULT_ADDR);
+static int cmd_init(int argc, char **argv)
+{
+    int res;
+
+    if (argc < 2) {
+        printf("usage: %s <addr (decimal)>\n", argv[0]);
+        return 1;
+    }
+
+    uint8_t addr = (uint8_t)atoi(argv[1]);
+
+    printf("Initializing SRF02 sensor at I2C_DEV(%i), address is 0x%02x\n... ",
+           TEST_SRF02_I2C, (int)addr);
+    res = srf02_init(&dev, TEST_SRF02_I2C, addr);
     if (res < 0) {
         puts("[Failed]");
         return 1;
@@ -55,10 +72,46 @@ int main(void)
     else {
         puts("[Ok]\n");
     }
-
-    while(1) {
-        xtimer_usleep_until(&wakeup, SAMPLE_PERIOD);
-        uint16_t distance = srf02_get_distance(&dev, TEST_MODE);
-        printf("distance = %i cm\n", distance);
-    }
+    return 0;
+}
+
+static int cmd_sample(int argc, char **argv)
+{
+    (void)argc;
+    (void)argv;
+    sample_loop();
+
+    return 0;
+}
+
+static int cmd_set_addr(int argc, char **argv)
+{
+    uint8_t new_addr;
+
+    if (argc < 2) {
+        printf("usage: %s <new_addr (decimal)>\n", argv[0]);
+        return 1;
+    }
+
+    new_addr = (uint8_t)atoi(argv[1]);
+    srf02_set_addr(&dev, new_addr);
+    printf("Set address to %i (0x%02x)\n", (int)new_addr, (int)new_addr);
+    return 0;
+}
+
+static const shell_command_t shell_commands[] = {
+    { "init", "initialize a device", cmd_init },
+    { "sample", "start sampling", cmd_sample },
+    { "addr", "reprogram the devices address", cmd_set_addr },
+    { NULL, NULL, NULL }
+};
+
+int main(void)
+{
+    puts("\nSRF02 Ultrasonic Range Sensor Test\n");
+    puts("This test will sample the sensor once per second and display the\n"
+         "result\n");
+
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(shell_commands, line_buf, SHELL_DEFAULT_BUFSIZE);
 }