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CC2500 module


Ok Moderators, My problem is i have two CC2500 modulehttp://thinklabs.in/shop/product_info.php?cPath=67&products_id=186 which supports 5V TTL logic level, But playing with my 3pi for 6 months i think i learnt that is supports voltage levels till 3.3V(though the motors are running on higher voltage thanks to the voltage booster), So, just employing a voltage regulator How do i interface the module to my 3pi.
Do i just Connect PD0 to the Rx and PD1 to the Tx and the VCC and GND, Will that do?
Or do i need to do something else also, Moreover please tell me if i have to remove any jumpers from the 3pi, And will any of the Leds on the 3pi flicker after interfacing the RF module.
Please help

Need some help in Programming


Both the 3pi and that module run at 5V, so there should be no problem with voltage levels. Your RX/TX connections are backwards - RX on the module should connect to TX (PD1) on the 3pi, and TX on the module should connect to RX (PD0) on the 3pi. You will definitely need to connect GND to GND. PD1 is shared with the red LED, so it will be mostly lit when you have enabled the serial port on the 3pi.

Beyond that, I would have to see a datasheet or User’s Guide for the module to give you advice. Do you have a link to one? For example, the CC2500 module might have a built-in regulator, which would mean that you could power it from the 9.25 output on the 3pi. There might also be pins, like a reset line, that need to be connected.

By the way, I recommend taking a look at the serial slave program for the 3pi to get ideas about programming your communication protocol.



Thank you Paul, Yes, Paul you are Right…I have to connect the Reset Also, I have attached all the Documents that i had for the Module, Please have a Look and tell me.
Wireless control.doc (867 KB)
CC2500 Module.pdf (83.6 KB)


Well, none of the documents you sent explain what you are supposed to do with “VCC”. Do you know how to supply power to this board?



That is Also Where i problem Lies, I asked them and they told me that the module that i will be connecting my PC with can have a separate power supply of 5v, or can be powered from the USB, the bot’s VCC must be connected to the modules VCC, So Do the 3pi Gives 5v output in its VCC pin…


Yes, VCC on the 3pi is 5V, so if that is what you need, you can use it.



Thank you Paul, Just one last question that is If i am using the VCC of the 3pi for the module, Will the other circuitry may behave somewhat differently (like the voltage boosters, motor driver) as i think all the modules are driving current from the same source, isn’t it?
If all the other components on the 3pi works fine then i can use the VCC pin for the RF module otherwise is i Attach another 5V li-ion cell to the module will there be any problem??


The VCC line on the 3pi can provide at least 100mA before the voltage starts dropping. It would be nice to have some specifications on your module so that we could be sure, but it is probably fine. I would not recommend connecting additional 5V supplies unless you really know what you are doing.



where is reset on 3pi for serial comm ?



The 3pi does not have a reset “for serial comm” - there is no such thing. It has a reset pin that will cause the board to reset - that is what the reset button does.

You can connect the reset pin of the 3pi to the reset pin of your module, so that they both reset at the same time, or you can connect an I/O line of the 3pi to the reset pin of your module, so that the module can reset under the control of your program. Which one do you want to do?



no its ok
i they said no need to connect the reset.

One offtopic thing
how to receive the serial data
i know it is serial_send( )
but how to receive from buffer
is it UDR



There are a number of ways to receive data. Did you read the example program above? You can also read the command reference for a list of functions.