求助：12864液晶显示MPU6050数据

我爱胆机妙音

先上代码

1. #include "Wire.h"
   
2. 
   
3. // I2Cdev and MPU6050 must be installed as libraries, or else the .cpp/.h files
   
4. // for both classes must be in the include path of your project
   
5. #include "I2Cdev.h"
   
6. #include "MPU6050.h"
   
7. #include "ST7920.h"
   
8. 
   
9. 
   
10. // class default I2C address is 0x68
    
11. // specific I2C addresses may be passed as a parameter here
    
12. // AD0 low = 0x68 (default for InvenSense evaluation board)
    
13. // AD0 high = 0x69
    
14. MPU6050 accelgyro;
    
15. ST7920 lcd;
    
16. int16_t ax, ay, az;
    
17. int16_t gx, gy, gz;
    
18. 
    
19. #define LED_PIN 13
    
20. bool blinkState = false;
    
21. char str[16];//define variable
    
22. float gx1;
    
23. void setup() {
    
24.     // join I2C bus (I2Cdev library doesn't do this automatically)
    
25.     Wire.begin();
    
26. 
    
27.     // initialize serial communication
    
28.     // (38400 chosen because it works as well at 8MHz as it does at 16MHz, but
    
29.     // it's really up to you depending on your project)
    
30.     Serial.begin(38400);
    
31. 
    
32.     // initialize device
    
33.     Serial.println("Initializing I2C devices...");
    
34.     accelgyro.initialize();
    
35. 
    
36.     // verify connection
    
37.     Serial.println("Testing device connections...");
    
38.     Serial.println(accelgyro.testConnection() ? "MPU6050 connection successful" : "MPU6050 connection failed");
    
39. 
    
40.     // configure Arduino LED for
    
41.     pinMode(LED_PIN, OUTPUT);
    
42.     //LCD initialize
    
43.     lcd.LCD_Init();
    
44.     lcd.LCD_ClearRam();
    
45. }
    
46. 
    
47. void loop() {
    
48.     // read raw accel/gyro measurements from device
    
49.     accelgyro.getMotion6(&ax, &ay, &az, &gx, &gy, &gz);
    
50. 
    
51.     // these methods (and a few others) are also available
    
52.     //accelgyro.getAcceleration(&ax, &ay, &az);
    
53.     //accelgyro.getRotation(&gx, &gy, &gz);
    
54. 
    
55.     // display tab-separated accel/gyro x/y/z values
    
56.     Serial.print("a/g:\t");
    
57.     Serial.print(ax); Serial.print("\t");
    
58.     Serial.print(ay); Serial.print("\t");
    
59.     Serial.print(az); Serial.print("\t");
    
60.     Serial.print(gx); Serial.print("\t");
    
61.     Serial.print(gy); Serial.print("\t");
    
62.     Serial.println(gz);
    
63. 
    
64.     // blink LED to indicate activity
    
65.     blinkState = !blinkState;
    
66.     digitalWrite(LED_PIN, blinkState);
    
67.       
    
68.       gx1=gx/131.0;//x axis gyro data after converting to international unit
    
69.         sprintf(str,"%2d",gx1);//convert float to string
    
70.         lcd.LCD_DisplayStrings(0,0,str);//LCD display converted data
    
71.         delay(1000);
    
72. 
    
73.        

复制代码

Arduino1.0.1没法写汉语，只好用英语注释了，请见谅。
其中 gx1=gx/131.0;//x axis gyro data after converting to international unit 这一行，读取的gx1数据正常，是x轴角速度
我想把它显示到12864液晶上，但是显示上去后却是正负变化无常的6位整数（陀螺仪静止时正常的gx1数据在0.01左右）

若把“%2d”改为“%2f” 则屏幕上会显示一个问号
请问怎样才能在12864上显示浮点数？
百思不得其解啊 请大家指教
谢谢

jinglishi

应该是有个类似库的东西，？的原因是因为不直持浮点。我用其它的IDE 也是这样的问题，后来加了浮点库。
但arduino的浮点库不会加。
同样请高人指点。

jinglishi

帮忙顶一下这个贴子。