add code for GPS I2C

2026-05-28 01:53:48 +08:00 · 2009-10-10 09:36:54 +00:00
parent 9b55bb5655
commit e99d91e1fe
3 changed files with 121 additions and 0 deletions
@@ -0,0 +1,14 @@
+<!DOCTYPE module SYSTEM "module.dtd">
+
+<module name="gps_i2c">
+  <header>
+    <file name="gps_i2c.h"/>
+  </header>
+  <init fun="gps_i2c_init()"/>
+  <periodic fun="gps_i2c_periodic()" freq="4." delay="4" autorun="TRUE"/>
+  <event fun="gps_i2c_event()"/>
+  <makefile target="ap">
+    <file name="gps_i2c.c"/>
+  </makefile>
+</module>
+
@@ -0,0 +1,88 @@
+#include "gps_i2c.h"
+#include "i2c.h"
+
+uint8_t gps_i2c_buf[GPS_I2C_BUF_SIZE];
+uint8_t gps_i2c_insert_idx, gps_i2c_extract_idx;
+
+
+/* u-blox5 protocole, page 4 */
+#define GPS_I2C_SLAVE_ADDR 0x42
+#define GPS_I2C_ADDR_NB_AVAIL_BYTES 0xFD
+#define GPS_I2C_ADDR_DATA 0xFF
+
+#define GPS_I2C_STATUS_IDLE                   0
+#define GPS_I2C_STATUS_ASKING_DATA            1
+#define GPS_I2C_STATUS_ASKING_NB_AVAIL_BYTES  2
+#define GPS_I2C_STATUS_READING_NB_AVAIL_BYTES 3
+#define GPS_I2C_STATUS_READING_DATA           4
+
+static uint8_t gps_i2c_status;
+static bool_t gps_i2c_done;
+static uint8_t gps_i2c_nb_avail_bytes;
+static uint8_t data_buf_len;
+
+void
+gps_i2c_init(void) {
+  gps_i2c_status = GPS_I2C_STATUS_IDLE;
+  gps_i2c_done = TRUE;
+}
+
+static inline void
+gps_i2c_ask_read(uint8_t addr) {
+  i2c0_buf[0] = addr;
+  i2c0_transmit(GPS_I2C_SLAVE_ADDR, 1, &gps_i2c_done);
+  gps_i2c_done = FALSE;
+}
+
+static inline void
+continue_reading(void) {
+  if (gps_i2c_nb_avail_bytes > 0) {
+    gps_i2c_ask_read(GPS_I2C_ADDR_DATA);
+    gps_i2c_status = GPS_I2C_STATUS_ASKING_DATA;
+  } else {
+    gps_i2c_status = GPS_I2C_STATUS_IDLE;
+  }
+}
+
+void
+gps_i2c_periodic(void) {
+  // We should check gps_i2c_done == true
+  gps_i2c_ask_read(GPS_I2C_ADDR_NB_AVAIL_BYTES);
+  gps_i2c_status = GPS_I2C_STATUS_ASKING_NB_AVAIL_BYTES;
+}
+
+void
+gps_i2c_event(void) {
+  if (gps_i2c_done) {
+    switch (gps_i2c_status) {
+    case GPS_I2C_STATUS_ASKING_NB_AVAIL_BYTES:
+      i2c0_receive(GPS_I2C_SLAVE_ADDR, 2, &gps_i2c_done);
+      gps_i2c_done = FALSE;
+      gps_i2c_status = GPS_I2C_STATUS_READING_NB_AVAIL_BYTES;
+      break;
+
+    case GPS_I2C_STATUS_READING_NB_AVAIL_BYTES:
+      gps_i2c_nb_avail_bytes = (i2c0_buf[0]<<8) | i2c0_buf[1];
+      continue_reading();
+      break;
+
+    case GPS_I2C_STATUS_ASKING_DATA:
+      data_buf_len = Min(gps_i2c_nb_avail_bytes, I2C0_BUF_LEN);
+      gps_i2c_nb_avail_bytes -= data_buf_len;
+
+      i2c0_receive(GPS_I2C_SLAVE_ADDR, data_buf_len, &gps_i2c_done);
+      gps_i2c_done = FALSE;
+      gps_i2c_status = GPS_I2C_STATUS_READING_DATA;
+      break;
+      
+    case GPS_I2C_STATUS_READING_DATA: {
+      uint8_t i;
+      for(i = 0; i < data_buf_len; i++) {
+	gps_i2c_AddCharToBuf(i2c0_buf[i]);
+      }
+      continue_reading();
+      break;
+    }
+    }
+  }
+}
@@ -0,0 +1,19 @@
+#ifndef GPS_I2C
+#define GPS_I2C
+
+#include <inttypes.h>
+
+#define GPS_I2C_BUF_SIZE 256
+extern uint8_t gps_i2c_buf[GPS_I2C_BUF_SIZE];
+extern uint8_t gps_i2c_insert_idx, gps_i2c_extract_idx;
+
+void gps_i2c_init(void);
+void gps_i2c_event(void);
+void gps_i2c_periodic(void);
+
+#define gps_i2c_AddCharToBuf(_x) { \
+  gps_i2c_buf[gps_i2c_insert_idx] = _x; \
+  gps_i2c_insert_idx++; /* size=256, No check for buf overflow */ \
+}
+
+#endif // GPS_I2C