can I connect two c2000's gpio together?

but when power on,  the dsp start to run the program, i can not configure the gpio immediately, then what should i do?  does a buffer needed?

if a buffer needed , which buffer you can suggest?

david said:

but when power on,  the dsp start to run the program, i can not configure the gpio immediately, then what should i do?  does a buffer needed?

Do you have the particular devices you are planning to connect, meaning which part numbers?  This always helps the discussion.

Generically speaking, if the pins you are connecting together both power up as inputs, you will not need any mechanism to electrically isolate them.  However, if they both power up as outputs, then what Lori mentioned is a concern and you would very likely need a way to address that, either with a buffer or something equivalent.

You have also asked about which buffer.  This again comes down to your application.  A series of questions below show help guide you to identify the appropriate implementation.

1) Are you going to implement this interface as a uni-directional interface (ie. one output, one input)?
2) Will this need to be a bi-directional interface emulating something like a uWire or 1-wire interface?
3) What speed or frequency will the interface need to operate at?

Please provide more information on your system ... do you need to connect two IO as inputs only, or output only or in/out combinations? As it is already mentioned some configurations are possible/allowed and some are not.

many thanks to all. i want to connect two tms320f28335's gpio together , and one input ,another output. and the input and output function are fixed after power on. the speed are about 10kHz.  using in the industry environment to control a huger motor.  can you give me some suggestion? i look forward to it. thanks.

For the lack of a better understanding on your system, to me your description sounds like a loop-back configuration, taking output of a pin back to an input. Would you please explain how this configuration is utilized in your application? loop back is useful during debugging of a peripheral like communication ports but I am not clear how that concept will be utilized in a real system. Thank you in advance for your time.

ok, i am sorry, i want to using two 28335 in my system. and they have some messages to exchange with each other. so i need to connect one dsp's gpio to another dsp's gpio. so i want to know if i connect them together , what should i do,  i need a robust method. i don't know if i have explain clearly.   thank you.

Thanks for the description - have you considered using any communication ports available in these devices? Unless you are looking for a simple on/off type of messages having a proper communication port running will be a robust way to communicate between devices. If it is a point-to-point setup (two devices) then protocols like SPI or SCI will be straight forward way to communicate. If you are looking to coomunicate between more than two devices then look for I2C type of modules. Anyway, as answered before you should be able to connect two I/Os.

Yes, you are right , I am using the MCBSP port as my main commuication port. and the gpio  is my assitant method. But i also should face to the problem i metioned above. Because after the DSP is power on and before you config the gpio to the MCBSP function,  you also need to face the problem that if connect the two dsp's gpio togher, what should i do.
and a new problem have ring during my design. commonly we will connect the 28335's CAN port to CAN drivers like TJA1050 and so on. But if i connect the two 28335's CAN port directly,what should i do.  because they are very near, and point to point. So I doesn't want to using CAN driver and connect the TWO chips' CAN port directly. and i want to know if i could connect the TWOchips' CAN port directly. if there are some things i should avoid.

david said:

Yes, you are right , I am using the MCBSP port as my main commuication port. and the gpio  is my assitant method. But i also should face to the problem i metioned above. Because after the DSP is power on and before you config the gpio to the MCBSP function,  you also need to face the problem that if connect the two dsp's gpio togher, what should i do.

The GPIO's will be inputs and not driven by either device until you configure them appropriately.

david said:

But if i connect the two 28335's CAN port directly,what should i do.  because they are very near, and point to point. So I doesn't want to using CAN driver and connect the TWO chips' CAN port directly. and i want to know if i could connect the TWOchips' CAN port directly. if there are some things i should avoid.

I'm not a CAN expert, but I don't think you can connect them directly.  My understanding is the bus will need a transceiver for each CAN and the bus will need to be terminated properly on both ends.

-Lori

thank you !  About the GPIO problem i think i have get the result. and i want more advice about the CAN port problem.i don't want to place two can driver between the two dsp. i think there maybe some method to avoid it.