I have been using avr microcontrollers for last 1 year but never faced this problem. Yesterday I was trying to connect a Arduino mini pro with a USB-Serial interface(supplied by Decagon, DevName DecagonUCA, Chip:Silabs CP2024). I have used this same device in same configuration several times in last 3/4 months.
But only change in code yesterday was that i was throwing some data continuously as the chip powers up. The Operating System (Win7) detects a new device Microsoft serial ballpoint. Now this makes two problems.
- The new device uses the serial port you are using. Makes it busy so you can’t use it.
- The device assumes the sensor readings you are sending as mouse pointer positions, so it moves the pointer randomly(assuming your data is random) and creates mouse clicks. Now you can’t uninstall the device as your mouse pointer is not in your control.
I removed the USBSerial cable and searched the name of the driver installed, google displayed a number of forum users complaining about this problem. https://www.google.co.in/search?q=microsoft+serial+ballpoint Most of the users are using USB GPS device. I guess any device which continously sends alpha numeric data confused as serial ballpoint. Anyway i want to know what is the actual serial ballpoint protocol
———————————–Serial BallPoint Protocol Start——————————————————–
The old MicroSoft serial mouse, while no longer in general use, can be employed to provide a low cost input device, for example, coupling the internal mechanism to other moving objects. The serial protocol for the mouse is 1200 baud, 7 bit, 1 stop bit, no parity. Every time the mouse changes state (moved or button pressed) a three byte “packet” is sent to the serial interface. For reasons known only to the engineers, the data is arranged as follows, most notably the two high order bits for the x and y coordinates share the first byte with the button status.
D6 D5 D4 D3 D2 D1 D0
1st byte 1 LB RB Y7 Y6 X7 X6
2nd byte 0 X5 X4 X3 X2 X1 X0
3rd byte 0 Y5 Y4 Y3 Y2 Y1 Y0
LB is the state of the left button, 1 = pressed, 0 = released.
RB is the state of the right button, 1 = pressed, 0 = released
X0-7 is movement of the mouse in the X direction since the last packet. Positive movement is toward the right.
Y0-7 is movement of the mouse in the Y direction since the last packet. Positive movement is back, toward the user.
Sample C code to decode three bytes from the mouse passed in “s”, the button and position (x,y) are returned.
s should consist of 3 bytes from the mouse
void DecodeMouse(unsigned char *s,int *button,int *x,int *y)
*button = ‘n’; /* No button – should only happen on an error */
if ((s & 0x20) != 0)
*button = ‘l’;
else if ((s & 0x10) != 0)
*button = ‘r’;
*x = (s & 0x03) * 64 + (s & 0x3F);
if (*x > 127)
*x = *x – 256;
*y = (s & 0x0C) * 16 + (s & 0x3F);
if (*y > 127)
*y = *y – 256;
- Alternative: https://www.kryslix.com/nsfaq/Q.12.html
———————————–Serial BallPoint Protocol End——————————————–
Solution 1, (NoSerialMice):
- To disable the detection of devices on COM ports in Windows NT/2000/XP: Go to: My Computer – Right Click – Properties | Advanced tab | Startup and Recovery – Settings | Edit. Make a backup copy of the Boot.ini file, (copy and paste in another location)
- Remove the hidden, system, and read-only attributes from the Boot.ini file. (Use Windows Explorer and right click on file, then properties.)
- Using a text editor (such as Notepad) open the Boot.ini file.(Double click on file, or right click and choose Notepad from the “Open With” option.)
- Add “/NoSerialMice” to the end of each entry in the [operating systems] section of Boot.ini. See the example below for more information
- Save Boot.ini and quit Notepad
- Shutdown and restart Windows
NOTE: The /NoSerialMice option is not case sensitive.
Solution 2: Disable serial mouse
You can disable serial mouse when its connected, but mostly in this type problem the mouse pointer keeps oscillating randomly so you can’t choose the device manager or disable the device.