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8 years, 2 months ago.
How to connect two ARM mbed together
Sorry I'm new to using ARM Embedded Systems so I know almost nothing. I have a group project and my task was to research on how to connect two ARM Mbed lpc1768 boards together (We are trying to build a remote control car I'm not exactly sure why we need to connect the two boards together).
So please if any has any ideas or any link or books they think can help with my question it will be very much appreciated.
3 Answers
8 years, 2 months ago.
I am curtly working on something similar. I am using a pair of xbee modules for communication.
8 years, 2 months ago.
Well - physically you need to make sure they use the same ground reference [ the minus voltage]
then the uart TX from one is connected to the RX of the other board. [use a secondary uart -
then the uart RX from one is connected to the TX of the other board. [not the USB programming one !!
use the Serial class/code to get a string [received or to transmit] I ;have no experience in this aspect
you also need to create a case structure tree to decide what to do with the string you received
_ I like to use the Coridium Corp ARMbasic for the mbed 1768 to program in.
_ My 'C' gets lost in some of the finer details and the ARMbasic IDE recovers nicely from my errors.
_ its an industrial type of Basic with lots of IO functions. It will do Linux under Wine with a few configs but is Windows focused
Hope this gets you in a direction Gary
8 years, 2 months ago.
As Gary indicated, serial is the simplest method. You can easily pass either individual bytes or with some fairly minimal extra software whole messages between them that way. Assuming you only have short distances (on an RC car they should be) then you can get almost 1Mb/s using serial.
The other advantage in serial is that if you get something like an FTDI TTL USB cable (see here) then you can use a PC to either listen in to the communications or replace one of the two mbeds, something that can be handy for debugging.
If you don't mind adding extra parts then you could use RS232 line drivers, that will give better noise immunity and longer distances.
If you want to me more like a real car you could use CAN, that is the standard computer bus within most cars. That will require driver ICs to be added and your maximum data rate will be a little lower but has a built in protocol, data is sent in packets of up to 8 bytes, each packet has an address which can be used to identify the type of information it contains. CAN is very good for noise immunity.
You can also play with thinks like USB, SPI, I2C or even ethernet. They will give you higher data rates but also generally add a little more complexity (especially USB or ethernet) . Probably not worth it unless you need to move a lot of data around, with some careful planning and design of the messages you are sending 1Mb/s is a lot of information.