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ez430 - f2013 or f2012 Communication with PC

Jordi Borras
Prodigy 10 points
Other Parts Discussed in Thread: MSP430F2013, CC2530, CC2531, REMOTI, MSP430F5529

Hello everyone,
I'm developing a peripheric like a mouse, with ez430-f2013 (or f2012): a special head-mouse for tetraplegic people.

I have problems with communication between eZ430-f2013 -> PC. I would send some data (6 bytes) to my computer. I try to adapt the msp430x20x3_ta_uart2400.c sample, but no data is received from PC.
I tried to do this with ps/2 port, RS232 port and USB port, connected to the P4 and P5 pins... without results.
How can I do this?

It seems that not signal is sended.

Thanks!

 

  • 0
    Intellectual 975 points

    try to check in the Oscilloscope where the Rx and Tx lines are connected 

    and check out the baud rate settings first 

  • 0
    Expert 1710 points

    You tried the PS2, RS232, and USB ports connected straight to a MSP430F2013 on GPIO P4/P5??

    I don't think that ANY of those port types are electrically compatible with the device you're using.

    USB port interfacing needs a special microcontroller with a USB device type port on it.  The ez430 kit with the USB interface does provide a USB interface to the MSP430F2013's Spy-By-Wire port for PC based debugging and flash memory programming, but USB is not a native function of the '2013 and you could not hook any of its pins to a USB port without some additional USB interface chips.  You should not use the 2013 for USB peripheral development.

    RS232 ports on PC computers and others use high positive and negative voltages such as -12V, +12V for the data signal levels.  Although the '2013 can simulate a UART if you program it to do so (it is not that easy since it lacks a proper hardware UART peripheral), you MUST use a level translator chip called a RS232 transceiver to interface the data lines on the physical RS232 port coming from the PC into ANY microcontroller so that the voltages and signal polarities will be translated to proper levels for the microcontroller which in the case of the MSP430 is probably 2.7 to 3.3 Volts maximum!  So you cannot interface this device easily to an RS232 port, I would suggest not to even try.

    PS/2 ports are based on serial 10 bit data word clocked shift registers  if I recall correctly.  Anyway they operate at +5V power supply and logic levels.  I suspect that you would also need a level translator to connect most current types of microcontroller to this kind of +5V TTL logic / power levels, such as a 2.7V-3.3V to +5V level transceiver interface chip or similar.  Otherwise you will not be successful and the microcontroller may be damaged, same as with the USB and RS-232 port cases.  Also the PS/2 protocol isn't really a UART protocol, so you'd need to write different kinds of software for this to work properly even if you had the right electrical interface.

    The only even slightly easy and proper thing to do would be to use the EZ-430 unit's USB debugging device as an interface to the USB port and connect your sensor switches to the I/O pins on the microcontroller and use the ex430's USB debugger capabilities to read your data, but this is really not so easy, and I would suggest that you should use a totally different chip to make your device because of the inappropriateness of directly interfacing this microcontroller to a PC.

    The CC2531 which you can't get samples of yet, though I think you can buy the evaluation module in a few different products has a built in USB device port which could I believe be programmed to be a HID (Human Interface Device) [mouse / joystick / keyboard type]  compatible unit for the PC.   This device is nice because it has a wireless radio modem in it and if you had one CC2531 with USB connected to the PC, and another board with a battery, your mouse-like sensors, and a CC2530 chip on it, you could have a wireless type of mouse so that the user would not have to have a physical connection to the PC if they are within a modest distance of the PC with its radio receiver.  This is not a very simple sort of hardware / software to make, though some of the RemoTI and CC2530DK types of development kits would make it a bit easier for you to prototype / demonstrate than building it all yourself which is an advanced software / hardware project.  Honestly I think some of the wireless / USB / HID development kits from MICROCHIP, or CYPRESS may be easier for you to use if you're not very advanced with engineering these kinds of systems.

    The MSP430F5529 also has a USB device port and similar capabilities to be programmed as a HID device.

    The TUSB3210 is a general purpose USB device microcontroller which can also be programmed to be a HID device.

    Cypress semiconductor also has many USB device microcontrollers that are intended to be a mouse like  [HID] device to the PC.  They have many development kits as well that can help you test such an application with little hardware / software engineering.

     

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