When I connected the FMS interface I built the other day to my new radio and the laptop I got a very jumpy signal. In the FMS Forum there where two different suggestions what might cause this, either to weak power in the serial port, or the reversed order of the signalcable from my Sanwa radio.
This guy had a similar problem but with another PIC interface, though for this one the source code is available. So maybe I will change mine to that one since the design was similar. Or just reprogram my PIC since I think the design is similar enough to do that, though I have to study it more carefully first.
Also the FMS Forum had a several posts on different hardware interfaces, maybe one can find a simple USB joystick based one there.
With the PIC interface, there could be several causes for it not to work.
First of all, what PIC did you use? If it is the 12F675, 12C508, 12C509, then the problem most propably lies in the programming of the chip. If it was programmed using a home build programmer, chances are that the calibration data was lost during the programming.
Secondly, the calibration bits could have been set incorrect or not set at all before programming. The above chips have to be set to Internal Oscilator with no clock output, and watchdog timer should be on.
Thirdly, another common problem is that most of the newer notebooks does not have a standard serial port anymore. To conserve battery power, the serial port signals was dropped to as low as 3.3V, too low for some of the PICs to operate correct. In some cases, this can be corrected by adding a seperate power supply to the interface.
With some of these newer serial ports, the output voltage levels were dropped, but the input voltages on the data line (pin 2) must still be able to switch correct between -5V and +5V. To be able to correct this problem, the interface must have a power supply, and the output of the PIC should be taken through a TTL to RS232 converter (MAX232 and 4 0.1uf caps).
Appart from the above issues, most other problems can be said to be construction problems, like not placing the NPN and PNP transistors correct in the circuit.
Also, try to see if it does not work when the baud rate is changed. There are two versions of the interface, one running at 19200 baud, the other at 9600 baud.
Should you have any further problems, feel free to contact me.
Regards
With the PIC interface, there could be several causes for it not to work.
First of all, what PIC did you use? If it is the 12F675, 12C508, 12C509, then the problem most propably lies in the programming of the chip. If it was programmed using a home build programmer, chances are that the calibration data was lost during the programming.
Secondly, the calibration bits could have been set incorrect or not set at all before programming. The above chips have to be set to Internal Oscilator with no clock output, and watchdog timer should be on.
Thirdly, another common problem is that most of the newer notebooks does not have a standard serial port anymore. To conserve battery power, the serial port signals was dropped to as low as 3.3V, too low for some of the PICs to operate correct. In some cases, this can be corrected by adding a seperate power supply to the interface.
With some of these newer serial ports, the output voltage levels were dropped, but the input voltages on the data line (pin 2) must still be able to switch correct between -5V and +5V. To be able to correct this problem, the interface must have a power supply, and the output of the PIC should be taken through a TTL to RS232 converter (MAX232 and 4 0.1uf caps).
Appart from the above issues, most other problems can be said to be construction problems, like not placing the NPN and PNP transistors correct in the circuit.
Also, try to see if it does not work when the baud rate is changed. There are two versions of the interface, one running at 19200 baud, the other at 9600 baud.
Should you have any further problems, feel free to contact me.
Regards
Hi Eric,
the problem was due to the calibration bit. I used the erasable version of the 12C509 (in an “older entry”:http://www.yelloworb.com/orbblog/archives/000070.html there is a “picture”:http://www.yelloworb.com/orbblog/archives/FMS_interface_top.html where one can see the version of PIC I use). Anyway once I changed to the non-erasable version and made sure I didnt overwrite the calibration bit during the programming all worked just fine. Thanks for the nice design!
Hi Eric,
the problem was due to the calibration bit. I used the erasable version of the 12C509 (in an “older entry”:http://www.yelloworb.com/orbblog/archives/000070.html there is a “picture”:http://www.yelloworb.com/orbblog/archives/FMS_interface_top.html where one can see the version of PIC I use). Anyway once I changed to the non-erasable version and made sure I didnt overwrite the calibration bit during the programming all worked just fine. Thanks for the nice design!
When do jou have the “USB04 JR”-interface??? I’ve a GRAUPNER transmitter and i want to connect it with a USB cable to FMS as a virtual joystick.
When do jou have the “USB04 JR”-interface??? I’ve a GRAUPNER transmitter and i want to connect it with a USB cable to FMS as a virtual joystick.