src/gy521_driver/gy521_driver.c

@@ -18,6 +18,8 @@ extern void _test_free(void* const ptr, const char* file, const int line);
 #define free(ptr) _test_free(ptr, __FILE__, __LINE__)
 #endif // UNIT_TESTING
 
+#define     NUM_ACCEL_REGS  6
+
 /*
  * ############################
  * REGISTER MAP 
@@ -25,6 +27,20 @@ extern void _test_free(void* const ptr, const char* file, const int line);
  */ 
 
 enum gy521_map {
+    accel_xouth = 0x3B,
+    accel_xoutl,
+    accel_youth,
+    accel_youtl,
+    accel_zouth,
+    accel_zoutl,
+    temp_outh,
+    temp_outl,
+    gyro_xouth,
+    gyro_xoutl,
+    gyro_youth,
+    gyro_youtl,
+    gyro_zouth,
+    gyro_zoutl,
     fifo_couth = 0x72,
     fifo_contl,
     fifo_r_w,
@@ -55,6 +71,23 @@ struct gy521_module{
     accel_values_struct accel;
 };
 
+/*
+ * ############################
+ * Helper/Private Functions
+ * ############################
+ */ 
+    
+uint8_t read_register(enum gy521_map reg)
+{
+    return 0;
+}
+
+uint8_t write_register(enum gy521_map reg)
+{
+    return 0;
+}
+
+
 /*
  * ############################
  * Function Definitions
@@ -75,6 +108,7 @@ void gy521_free(gy521_module *m)
     free(m);
 }
 
+
 _Bool gy521_init(gy521_module *m, uint8_t slave_address) {
     if((slave_address != TWI_GY521_ADDR1) && (slave_address != TWI_GY521_ADDR2)) { 
         m->slave_address = 0x0;
@@ -97,12 +131,25 @@ _Bool gy521_init(gy521_module *m, uint8_t slave_address) {
 }
 
 
-_Bool gy521_update_gyro(gy521_module *m)
+void gy521_update_gyro(gy521_module *m)
 {
-    return 0;
+ 
 }
 
-_Bool gy521_update_accel(gy521_module *m)
+void gy521_update_accel(gy521_module *m)
 {
-    return 0;
+    uint8_t read_regs[NUM_ACCEL_REGS] = {accel_xouth, accel_xoutl,
+            accel_youth, accel_youth,
+            accel_zouth, accel_zoutl};
+
+    /*update individually the structure by communicating with the device.*/
+    gy521_twi_rx(m->slave_address, read_regs, NUM_ACCEL_REGS);
+   
+    /*bitshift to reassembly the high/low regs into a single 16bit*/
+    m->accel.x = (read_regs[0] << 8) | read_regs[1];
+    m->accel.y = (read_regs[2] << 8) | read_regs[3];
+    m->accel.z = (read_regs[4] << 8) | read_regs[5];
+
 }
+
+

src/gy521_driver/gy521_driver.h

@@ -42,8 +42,8 @@ extern void (*gy521_twi_rx)(uint8_t, uint8_t*, uint8_t);
 
 struct gy521_module* gy521_new(void);
 _Bool gy521_init(struct gy521_module *m, uint8_t slave_address);
-_Bool gy521_update_gyro(struct gy521_module* m);
+void gy521_update_gyro(struct gy521_module* m);
-_Bool gy521_update_accel(struct gy521_module* m);
+void gy521_update_accel(struct gy521_module* m);
 void gy521_free(struct gy521_module *m);